ASTM D7935-20

Standard Test Method for Corrosion Test for Non-Aqueous Engine Coolants in Glassware

SIGNIFICANCE AND USE
4.1 This test method will generally distinguish between non-aqueous coolants that are definitely deleterious from the corrosion standpoint and those that are suitable for further evaluation. However, the results of this test method cannot stand alone as evidence of satisfactory corrosion inhibition. The actual service value of an engine coolant formulation can be determined only by more comprehensive bench, dynamometer, and field tests.
SCOPE
1.1 This test method covers a simple beaker-type procedure for evaluating the effects of non-aqueous engine coolants on metal specimens under controlled laboratory conditions (see Appendix X1).
Note 1: For more information on aqueous and non-aqueous engine coolants, see (Refs 1-9).2  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Some specific hazards statements are given in 10.1.7.2, 10.1.7.3, and 10.1.7.4.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2020
• ICS: 71.100.45 - Refrigerants and antifreezes
• Technical Committee: D15 - Engine Coolants and Related Fluids
• Drafting Committee: D15.22 - Non-Aqueous Coolants

Relations

• Replaces: ASTM D7935/D7935M-14 - Standard Test Method for Corrosion Test for Non-Aqueous Engine Coolants in Glassware
• Effective Date: 01-Jun-2020
• Refers: ASTM D1384-24 - Standard Test Method for Corrosion Test for Engine Coolants in Glassware
• Effective Date: 01-Jan-2024
• Refers: ASTM E230/E230M-23a - Standard Specification for Temperature-Electromotive Force (emf) Tables for Standardized Thermocouples
• Effective Date: 01-Nov-2023
• Refers: ASTM B36/B36M-23 - Standard Specification for Brass Plate, Sheet, Strip, And Rolled Bar
• Effective Date: 01-Oct-2023
• Refers: ASTM E230/E230M-23 - Standard Specification for Temperature-Electromotive Force (emf) Tables for Standardized Thermocouples
• Effective Date: 01-May-2023
• Refers: ASTM D1176-14(2019) - Standard Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
• Effective Date: 01-Oct-2019
• Refers: ASTM D1384-05(2019) - Standard Test Method for Corrosion Test for Engine Coolants in Glassware
• Effective Date: 01-Oct-2019
• Refers: ASTM B36/B36M-18 - Standard Specification for Brass Plate, Sheet, Strip, And Rolled Bar
• Effective Date: 01-Oct-2018
• Refers: ASTM E178-16 - Standard Practice for Dealing With Outlying Observations
• Effective Date: 01-Jun-2016
• Refers: ASTM D1176-14 - Standard Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
• Effective Date: 01-Apr-2014
• Refers: ASTM B36/B36M-13 - Standard Specification for Brass Plate, Sheet, Strip, And Rolled Bar
• Effective Date: 01-Oct-2013
• Refers: ASTM E1-13 - Standard Specification for ASTM Liquid-in-Glass Thermometers
• Effective Date: 01-May-2013
• Refers: ASTM D1384-05(2012) - Standard Test Method for Corrosion Test for Engine Coolants in Glassware
• Effective Date: 01-Apr-2012
• Refers: ASTM E230/E230M-11e1 - Standard Specification and Temperature-Electromotive Force (emf) Tables for Standardized Thermocouples
• Effective Date: 15-May-2011
• Refers: ASTM E230/E230M-11 - Standard Specification and Temperature-Electromotive Force (emf) Tables for Standardized Thermocouples
• Effective Date: 15-May-2011

Overview

ASTM D7935-20: Standard Test Method for Corrosion Test for Non-Aqueous Engine Coolants in Glassware provides a laboratory procedure to evaluate the corrosion effects of non-aqueous engine coolants on common metals found in engine cooling systems. Developed by ASTM International, this standard outlines a beaker-type glassware test intended as a screening tool to differentiate between coolants that are clearly unsuitable from a corrosion perspective and those potentially suitable for further investigation. While this method is a valuable first step in coolant evaluation, it should be complemented by more comprehensive simulations and field tests to confirm real-world performance.

Key Topics

• Corrosion Testing in Glassware: This standard describes a method where various metal specimens are fully immersed in a controlled mixture of non-aqueous coolant and synthetic corrosive water, maintained at a specific temperature over a set duration.
• Metals Evaluated: The metals typically tested include steel, copper, brass, solder, cast aluminum, and cast iron to mimic the diversity of automotive cooling system components.
• Test Procedure: Specimens are weighed before and after testing, allowing for quantitative measurement of corrosion (weight loss) after specific cleaning steps to remove corrosion products.
• Controlled Test Conditions: The coolant solution is kept at 96°C, and a defined aeration rate is maintained to simulate service environments.
• Data Interpretation: The results signal whether a coolant formulation is clearly deleterious or shows adequate corrosion inhibition for further testing, but do not, on their own, indicate suitability for service use.
• Screening Purpose: This test facilitates rapid comparison during coolant development and quality assessment, serving as a preliminary screening method.

Applications

• Coolant Formulation Screening: Useful for researchers and manufacturers to quickly identify non-aqueous coolant products with poor corrosion inhibition, saving time and resources before advancing to more complex tests.
• Quality Assurance: Laboratories and quality teams use the standard for routine evaluation of batch consistency and raw material changes in coolant manufacturing.
• Regulatory and Compliance Checks: The method can be referenced during product certification or to meet customer requirements for non-aqueous engine coolants.
• Benchmarking and Research: Provides a standardized basis for research studies and internal benchmarks in the cooling fluids and automotive sectors.

Related Standards

• ASTM D1384: Standard Test Method for Corrosion Test for Engine Coolants in Glassware (for aqueous coolants).
• ASTM D1176: Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes.
• ASTM E1 and E230/E230M: Specifications for temperature measuring instruments and thermocouples used in laboratory testing.
• ASTM B32 and B36/B36M: Specifications for materials commonly used in corrosion test specimens.
• SAE J814: SAE Information Report on Engine Coolants (for background and industry practices).

Practical Value

ASTM D7935-20 enables the automotive and coolant industry to:

• Screen out non-aqueous engine coolants with inadequate corrosion resistance efficiently.
• Standardize laboratory practices, ensuring consistency and reliability in corrosion testing.
• Support innovation by providing an accessible method to assess new coolant formulations before investing in costly real-world trials.
• Maintain quality control and compliance with industry or customer requirements relating to engine coolant corrosion performance.

By following ASTM D7935-20, organizations gain a valuable tool for early-stage evaluation, comparison, and continuous improvement of non-aqueous engine coolants, ensuring products moving forward to comprehensive testing have the necessary basic corrosion inhibition qualities.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7935 − 20
Standard Test Method for
Corrosion Test for Non-Aqueous Engine Coolants in
Glassware
This standard is issued under the fixed designation D7935; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope tions of Engine Coolants orAntirusts forTesting Purposes
D1384 Test Method for Corrosion Test for Engine Coolants
1.1 This test method covers a simple beaker-type procedure
in Glassware
for evaluating the effects of non-aqueous engine coolants on
E1 Specification for ASTM Liquid-in-Glass Thermometers
metal specimens under controlled laboratory conditions (see
E178 Practice for Dealing With Outlying Observations
Appendix X1).
E230/E230M Specification for Temperature-Electromotive
NOTE 1—For more information on aqueous and non-aqueous engine
Force (emf) Tables for Standardized Thermocouples
coolants, see (Refs 1-9).
2.2 ASTM Adjunct:
1.2 The values stated in SI units are to be regarded as
All-glass apparatus for corrosion test (2 drawings)
standard. The values given in parentheses after SI units are
provided for information only and are not considered standard.
3. Summary of Test Method
1.3 This standard does not purport to address all of the
3.1 In this test method, specimens of metals typical of those
safety concerns, if any, associated with its use. It is the
present in engine cooling systems are totally immersed in
responsibility of the user of this standard to establish appro-
aerated engine coolant solutions for 336 h at 96 °C (205 °F).
priate safety, health, and environmental practices and deter-
The corrosion-inhibitive properties of the test solution are
mine the applicability of regulatory limitations prior to use.
evaluated on the basis of the weight changes incurred by the
Some specific hazards statements are given in 10.1.7.2,
specimens.Eachtestisrunintriplicate,andtheaverageweight
10.1.7.3, and 10.1.7.4.
change is determined for each metal. A single test may
1.4 This international standard was developed in accor-
occasionally be completely out of line (see 11.3).
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4. Significance and Use
Development of International Standards, Guides and Recom-
4.1 This test method will generally distinguish between
mendations issued by the World Trade Organization Technical
non-aqueous coolants that are definitely deleterious from the
Barriers to Trade (TBT) Committee.
corrosion standpoint and those that are suitable for further
evaluation. However, the results of this test method cannot
2. Referenced Documents
stand alone as evidence of satisfactory corrosion inhibition.
2.1 ASTM Standards:
The actual service value of an engine coolant formulation can
B32 Specification for Solder Metal
be determined only by more comprehensive bench,
B36/B36M Specification for Brass Plate, Sheet, Strip, And
dynamometer, and field tests.
Rolled Bar
D1176 Practice for Sampling and Preparing Aqueous Solu-
5. Apparatus
5.1 Container, a 1000 mL, tall-form, spoutless beaker, made
1 of heat-resistant glass, for containing the non-aqueous engine
This test method is under the jurisdiction ofASTM Committee D15 on Engine
Coolants and Related Fluids and is the direct responsibility of Subcommittee coolantsolutionandtestspecimens.Thebeakershallbetightly
D15.22 on Non-Aqueous Coolants.
closed with a No. 15 rubber stopper, having drill holes to
Current edition approved June 1, 2020. Published June 2020. Originally
accommodate a water condenser, an aerator tube, and a
approved in 2014. Last previous edition approved in 2014 as D7935/D7935M–14.
temperature measuring instrument as shown in Fig. 1.
DOI: 10.1520/D7935-20
The boldface numbers in parentheses refer to the list of references at the end of
Optionally, an all-glass apparatus may be used.
this standard.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from ASTM International Headquarters. Order Adjunct No.
the ASTM website. ADJD1384. Original adjunct produced in 1980.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7935 − 20
FIG. 1 Metal Specimens and Equipment for 336 h Corrosion Test
5.2 Condenser, a water condenser of the reflux, glass-tube 6. Metal Test Specimens
NOTE 2—The specimens prescribed in this test method have been
type, having a 400 mm (16 in.) condenser jacket.
accepted by automobile manufacturers, but their composition may not be
5.3 AeratorTube,agas-dispersiontube,porositysize12-C,
the same as that of alloys currently used for engine cooling system
to ensure continuous aeration without plugging. components. Therefore, specimens other than those designated in this test
method may be used by mutual agreement of the parties involved.
5.4 Temperature Measuring Instrument (Environmentally
6.1 Type—The following metal test specimens, representa-
SafeThermometerorThermocouple),anASTMPartialImmer-
tive of cooling system metals, shall be used:
sion Temperature Measuring Instrument having a range from
6.1.1 Steel, UNS G10200 (SAE 1020), cut from 1.59 mm
–20 °C to 150 °C (0 °F to 302 °F) and conforming to the
( ⁄16 in.) cold-rolled sheet stock to size 50.8 mm by 25.4 mm
requirements for Thermometer 1C (1F), as prescribed in
(2 in. by 1 in.). Chemical composition of the carbon steel is as
Specification E1 or Thermocouple as summarized in Specifi-
follows: carbon, 0.17 to 0.23 %; manganese, 0.30 to 0.60 %;
cation E230/E230M.
phosphorus, 0.040 % maximum; sulfur, 0.050 % maximum.
5.5 Heater, a constant-temperature bath containing a high- 8
6.1.2 Copper, conforming to UNS C11000 (SAE CA110)
boiling liquid that is capable of giving continuous service with
or UNS C11300 (SAE CA113). Cold-rolled, cut from
the specified temperature control. The size of the bath will be
1.59 mm ( ⁄16 in.) sheet stock to size 50.8 mm by 25.4 mm
determined by the number of corrosion tests that are to be run
(2 in. by 1 in.).
concurrently.
6.1.3 Brass, conforming to Alloy UNS C26000 (SAE CA
260). Half-hard, cut from 1.59 mm ( ⁄16 in.) sheet stock to size
The sole source of supply of the apparatus known to the committee at this time
50.8 mm by 25.4 mm (2 in. by 1 in.).
is Corning Glass Works, 44-5 Crystal St., Corning, NY 14830. Gas-dispersion tube
6.1.4 Solder—A brass specimen as described in 6.1.3,
No. 39533, manufactured by Corning Glass Works, has generally been found
coated with solder conforming to Alloy Grade 30A (SAE 3A)
satisfactory for this purpose. Optionally, a capillary tip bleed tube with 7 mm
(0.28 in.) bore and 280 mm (11 in.) length may be used when consistent early
plugging of gas dispersion tubes occurs. The tube, catalog No. 7815-19, may be
obtainedfromCorningGlassWorks.Ifyouareawareofalternativesuppliers,please Complete sets or individual metal test specimens are available from (a)
provide this information toASTM International Headquarters. Your comments will ChemicalSpecialtiesManufacturersAssociation,Inc.,Suite1120,1001Connecticut
receive careful consideration at a meeting of the responsible technical committee, Ave., N.W., Washington, DC 20036; (b) Astro-Mechanics, Inc., 8500 Research
which you may attend. Blvd., Austin, TX 78766; (c) The Metaspec Company, P.O. Box 27707, San
If a water bath is used, a significant reduction in evaporation rate is achieved Antonio,TX78227;or(d)MetalSamplesCo.Inc.,P.O.Box8,Munford,AL36268.
by addition of floating plastic chips on the water surface. Unified Numbering System for Metals and Alloys, SAE-ASTM, July 1995.
D7935 − 20
of Specification B32. Solder-coated specimens may be followingorder:brassleg,copper,solder,brass,steel,castiron,
prepared, or used specimens recoated for reuse, by the proce- castaluminum,andbrassleg.Thespecimensshallbeseparated
dure given in Annex A1. A solid solder specimen cut from by 4.76 mm ( ⁄16 in.) thick solid metal spacers having a
1 17 7
1.59 mm ( ⁄16 in.) sheet stock ofAlloy Grade 30A(SAE 3A) to 6.75 mm ( ⁄64 in.) inside diameter and a 11.11 mm ( ⁄16 in.]
size 50.8 mm by 25.4 mm (2 in. by 1 in.) may be used subject outside diameter. Insulating spacers made from polytetrafluo-
to mutual agreement of the parties involved. The use of a solid roethylene shall be used between the brass legs and the
solder specimen must be reported along with the metal specimen“bundle,”andbetweenthebrassandsteelspecimens.
specimen weight loss results. Brass spacers shall be used between the brass, solder, and
6.1.4.1 When agreed upon between the supplier and the copper specimens, and steel spacers between the cast iron,
purchaser of engine coolants, the standard solder specimen steel, and cast aluminum specimens.The nut shall be tightened
may be replaced with one having a different alloy composition firmly to ensure good electrical contact between the test
than standardAlloy Grade 30Aor 30B. Use of specimens other specimens in each section of the “bundle.”
thanstandardAlloyGrade30Aor30Bshallbenotedinthetest 6.2.2 Alternate Metal Specimen Arrangement—When
report. agreed upon between the supplier and the purchaser, an
alternate metal specimen arrangement may be used to evaluate
NOTE 3—Where non-standard alloy is used, the standard flux shown in
multiple solder alloys, such as high lead Alloy Grade L50113
A1.1.5 may not be satisfactory. A low corrosive flux may be required.
consisting of 97 % lead, 2.5 % tin, 0.3 % silver, concurrently
6.1.5 Cast Aluminum, conforming to Alloy UNS A23190
withStandardAlloyGrade30Aor30B.Itisrecommendedthat
(SAE 329). Specimen size, 50.8 mm by 25.4 mm by 3.18 mm
the metal specimen arrangement be modified by replacing the
(2 in. by 1 in. by ⁄8 in.).
copper specimen with the high lead solder specimen and
6.1.6 Cast Iron, conforming to Alloy UNS F10007 (SAE
arranging specimens in the bundle as follows:
G3500). Specimen size, 50.8 mm by 25.4 mm by 3.18 mm
High Lead Brass Alloy Grade Steel Cast Iron Cast
(2 in. by 1 in. by ⁄8 in.).
Solder 30A or 30B Aluminum
6.2 Arrangement (See Fig. 2):
Use of alternate specimens and metal specimens arrange-
6.2.1 Metal Specimen Arrangement—None of the hardware
ments shall be noted in the test report.
used in metal specimen arrangement (metal specimen, screws,
washers, metal spacers, insulating sleeves, insulating spacers
7. Preparation of Test Specimens
and nuts) can be reused for a test. The metal test specimens
7.1 Sand the cast iron and cast aluminum specimens on the
shall be drilled through the center with a 6.75 mm ( ⁄64 in.)
25.4 mm by 50.8 mm (1 in. by 2 in.) cut surfaces with “coarse”
drill to accommodate a 50.8 mm (2 in.) 10–24 brass machine
grade (No. 1) emery cloth. Remove any burrs from coupon
screw covered with a thin-walled insulating sleeve. Polytetra-
edges and hole. Scrub all specimens vigorously, using a
fluoroethylene tubing with a 6.35 mm ( ⁄4 in.) outside diameter
moistened bristle brush and ground pumice powder or fine
1 1
1.59 mm ( ⁄16 in.) wide and a wall thickness of 0.4 mm ( ⁄64 in.)
silicon carbide grit until the entire metal area is bright, shiny,
is satisfactory. Two half-hard brass legs shall be cut from
and free from any visible oxide film or tarnish.
1.59 mm ( ⁄16 in.) sheet stock to size 50.8 mm by 25.4 mm
(2 in. by 1 in.). A 6.35 mm ( ⁄4 in.) diameter hole shall be 7.2 Rinse the specimens thoroughly with tap water; then
drilledineachlegwiththecenter6.35mm( ⁄4in.)fromthetop rinse with acetone, dry, and weigh to the nearest 1 mg. Cast
and 12.7 mm ( ⁄2 in.) from each side.The test “bundle” shall be aluminum specimens should be dried in a 100 °C oven for 1 h,
made up on the insulated screw with the specimens in the to a constant weight, prior to recording the weight.
FIG. 2 Metal Specimen Arrangement
D7935 − 20
NOTE 4—If the test specimens are not to be used immediately, keep
10.1.3 Pour 750 mL of the prepared test solution into the
them in a desiccator until required.
1000 mL beaker.
10.1.4 Fit the condenser and aeration tube to the beaker, and
8. Test Solutions
set the aeration rate at 100 mL/min, using a flow meter or other
8.1 The concentration of the non-aqueous engine coolant to
suitable device.
be tested shall be as follows:
10.1.5 Raise the temperature of the test solution to 96 °C
8.1.1 Engine Coolant—The non-aqueous coolant shall be
(205 °F). Pass water through the condenser at a rate sufficient
mixed with the proper quantity of corrosive water to give a test
to maintain adequate cooling.
solution containing a mixture of 94 volume % non-aqueous
10.1.6 Check the tests once each working day to ensure
coolant with six volume % corrosive water.
proper solution temperature, aeration rate, and solution level.
8.1.2 Corrosive Water (Note 5)—The corrosive water shall
The tests may operate unattended on weekends and holidays.
contain100ppmeachofsulfate,chloride,andbicarbonateions
Make up evaporation losses during the corrosion tests by
introduced as sodium salts.
addition of distilled or deionized water.
8.2 Preparation of Sample—The preparation of the sample
10.1.7 At the end of the test, immediately disassemble
shall be done in accordance with Practice D1176, except that
specimens and brush very lightly with a soft bristle brush and
thecorrosivewatershallbeusedfordilutioninsteadofdistilled
water to remove loosely held corrosion products. To remove
water. Thus, any insoluble materials will be included in the
the more tenacious corrosion products and films, the individual
representative sample.
specimens shall then be subjected to additional cleaning
treatments as follows:
NOTE 5—The specified corrosive water can be prepared by dissolving
the following amounts of anhydrous sodium salts in a quantity of distilled
10.1.7.1 Iron and Steel—Remove adherent deposits by
or deionized water.
means of a brass scraper or brass bristle brush, followed by
sodium sulfate 148 mg
scrubbing with a wet bristle brush and fine pumice to clean the
sodium chloride 165 mg
specimen completely.
sodium bicarbonate 138 mg
10.1.7.2 Copper and Brass—Dip ina1+1 mixture of
The resulting corrosive water solution should be made up to
concentrated HCl (sp gr 1.19) and water for 15 s to remove
a volume of 1 L with distilled or deionized water at 20 °C.
tarnish films, rinse with tap water to remove acid, and scrub
8.2.1 If relatively large amounts of corrosive water are
with a wet bristle brush and fine pumice powder. (Warning—
needed for testing, a concentrate may be prepared by dissolv-
HCl is a strong acid.Avoid contact with skin and eyes. Handle
ing ten times the above amounts of the three chemicals, in
in a fume hood.)
distilled or deionized water, and adjusting the total volume to
10.1.7.3 Aluminum—In a fume hood, dip for 10 min in an
1 L by further additions of distilled or deionized water. When
aqueous solution containing four parts concentrated nitric acid
needed, the water concentrate is diluted to the ratio of one part
(HNO , 70 mass %) plus one part distilled water at 25 °C
by volume of concentrate to nine parts of distilled or deionized
(77 °F). Rinse thoroughly with water, then brush very lightly
water.
with a soft bristle brush to remove any loose films, and again
9. Test Conditions rinse with water. Dry the specimen in a 100 °C oven for 1 h,
toaconstantweightpriortorecordingtheweight.(Warning—
9.1 Beaker Assembly—The arrangement of the assembled
HNO is a strong toxic oxidant and acid. Avoid contact with
metal specimens with relation to the aerator tube and other
skin, eyes, and clothing. Do not breathe vapor. Handle in a
components is shown in Fig. 1. Note that the tip of the
fume hood.)
condenser just emerges from the bottom of the rubber stopper.
10.1.7.4 Solder—Immerse for 5 min in boiling 1 % glacial
9.2 Test Temperature—The test solution shall be maintained
acetic acid. Rinse in water to remove the acid, and brush very
at a temperature of 96 °C 6 2 °C (205 °F 6 4 °F).
gently with a soft bristle brush to remove any loosened
9.3 Aeration Rate—The aeration rate shall be 100 mL⁄min
material. (Warning—Avoid contact with skin and eyes with
6 10 mL⁄min. The aerator tube should be located at least 12.7 glacial acetic acid. Handle in a fume hood.)
mm ( ⁄2 in.) away from the test “bundle
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7935/D7935M − 14 D7935 − 20
Standard Test Method for
Corrosion Test for Non-Aqueous Engine Coolants in
Glassware
This standard is issued under the fixed designation D7935/D7935M;D7935; the number immediately following the designation indicates
the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers a simple beaker-type procedure for evaluating the effects of non-aqueous engine coolants on metal
specimens under controlled laboratory conditions (see Appendix X1).
NOTE 1—For more information on aqueous and non-aqueous engine coolants, see (Refs 1-9).
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined. Some values have only SI units because the
inch-pound equivalents are not used in practice.given in parentheses after SI units are provided for information only and are not
considered standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. Some specific hazards statements are given in 10.1.7.2, 10.1.7.3, and 10.1.7.4.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
B32 Specification for Solder Metal
B36/B36M Specification for Brass Plate, Sheet, Strip, And Rolled Bar
D1176 Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antirusts for Testing Purposes
D1384 Test Method for Corrosion Test for Engine Coolants in Glassware
E1 Specification for ASTM Liquid-in-Glass Thermometers
E178 Practice for Dealing With Outlying Observations
E230/E230M Specification for Temperature-Electromotive Force (emf) Tables for Standardized Thermocouples
2.2 ASTM Adjunct:
All-glass apparatus for corrosion test (2 drawings)
3. Summary of Test Method
3.1 In this test method, specimens of metals typical of those present in engine cooling systems are totally immersed in aerated
engine coolant solutions for 336 h at 96°C [205°F].96 °C (205 °F). The corrosion-inhibitive properties of the test solution are
evaluated on the basis of the weight changes incurred by the specimens. Each test is run in triplicate, and the average weight change
is determined for each metal. A single test may occasionally be completely out of line (see 11.3).
This test method is under the jurisdiction of ASTM Committee D15 on Engine Coolants and Related Fluids and is the direct responsibility of Subcommittee D15.22 on
Non-Aqueous Coolants.
Current edition approved June 1, 2014June 1, 2020. Published August 2014June 2020. Originally approved in 2014. Last previous edition approved in 2014 as
D7935/D7935M–14. DOI: 10.1520/D7935_D7935M–1410.1520/D7935-20
The boldface numbers in parentheses refer to the list of references at the end of this standard.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
Available from ASTM International Headquarters. Order Adjunct No. ADJD1384. Original adjunct produced in 1980.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7935 − 20
4. Significance and Use
4.1 This test method will generally distinguish between non-aqueous coolants that are definitely deleterious from the corrosion
standpoint and those that are suitable for further evaluation. However, the results of this test method cannot stand alone as evidence
of satisfactory corrosion inhibition. The actual service value of an engine coolant formulation can be determined only by more
comprehensive bench, dynamometer, and field tests.
5. Apparatus
5.1 Container, a 1000-mL,1000 mL, tall-form, spoutless beaker, made of heat-resistant glass, for containing the non-aqueous
engine coolant solution and test specimens. The beaker shall be tightly closed with a No. 15 rubber stopper, having drill holes to
accommodate a water condenser, an aerator tube, and a temperature measuring instrument as shown in Fig. 1. Optionally, an
all-glass apparatus may be used.
5.2 Condenser, a water condenser of the reflux, glass-tube type, having a 400-mm [16-in.]400 mm (16 in.) condenser jacket.
5.3 Aerator Tube, a gas-dispersion tube, porosity size 12-C, to ensure continuous aeration without plugging.
5.4 Temperature Measuring Instrument (Environmentally Safe Thermometer or Thermocouple), an ASTM Partial Immersion
Temperature Measuring Instrument having a range from –20–20 °C to 150°C [0150 °C (0 °F to 302°F]302 °F) and conforming to
the requirements for Thermometer 1°C [1°F],1C (1F), as prescribed in Specification E1 or Thermocouple as summarized in
Specification E230/E230M.
FIG. 1 Metal Specimens and Equipment for 336–h336 h Corrosion
Test
The sole source of supply of the apparatus known to the committee at this time is Corning Glass Works, 44-5 Crystal St., Corning, NY 14830. Gas-dispersion tube No.
39533, manufactured by Corning Glass Works, has generally been found satisfactory for this purpose. Optionally, a capillary tip bleed tube with 7-mm [0.28-in.]7 mm
(0.28 in.) bore and 280-mm [11.2-in.]280 mm (11 in.) length may be used when consistent early plugging of gas dispersion tubes occurs. The tube, catalog No. 7815-19, may
be obtained from Corning Glass Works. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will
receive careful consideration at a meeting of the responsible technical committee, which you may attend.
D7935 − 20
5.5 Heater, a constant-temperature bath containing a high-boiling liquid that is capable of giving continuous service with the
specified temperature control. The size of the bath will be determined by the number of corrosion tests that are to be run
concurrently.
6. Metal Test Specimens
NOTE 2—The specimens prescribed in this test method have been accepted by automobile manufacturers, but their composition may not be the same
as that of alloys currently used for engine cooling system components. Therefore, specimens other than those designated in this test method may be used
by mutual agreement of the parties involved.
6.1 Type—The following metal test specimens, representative of cooling system metals, shall be used:
6.1.1 Steel, UNS G10200 (SAE 1020), cut from 1.59-mm [1.59 mm ( ⁄16-in.] in.) cold-rolled sheet stock to size 50.850.8 mm
by 25.4 mm [2(2 in. by 1 in.].in.). Chemical composition of the carbon steel is as follows: carbon, 0.17 to 0.23 %; manganese, 0.30
to 0.60 %; phosphorus, 0.040 % maximum; sulfur, 0.050 % maximum.
8 8
6.1.2 Copper, conforming to UNS C11000 (SAE CA110) or UNS C11300 (SAE CA113). Cold-rolled, cut from 1.59-mm
[1.59 mm ( ⁄16-in.] in.) sheet stock to size 50.850.8 mm by 25.4 mm [2(2 in. by 1 in.].in.).
6.1.3 Brass, conforming to Alloy UNS C26000 (SAE CA 260). Half-hard, cut from 1.59-mm [1.59 mm ( ⁄16-in.] in.) sheet stock
to size 50.850.8 mm by 25.4 mm [2(2 in. by 1 in.].in.).
6.1.4 Solder—A brass specimen as described in 6.1.3, coated with solder conforming to Alloy Grade 30A (SAE 3A) of
Specification B32. Solder-coated specimens may be prepared, or used specimens recoated for reuse, by the procedure given in
Annex A1. A solid solder specimen cut from 1.59-mm [1.59 mm ( ⁄16-in.] in.) sheet stock of Alloy Grade 30A (SAE 3A) to size
50.850.8 mm by 25.4 mm [2(2 in. by 1 in.]in.) may be used subject to mutual agreement of the parties involved. The use of a solid
solder specimen must be reported along with the metal specimen weight loss results.
6.1.4.1 When agreed upon between the supplier and the purchaser of engine coolants, the standard solder specimen may be
replaced with one having a different alloy composition than standard Alloy Grade 30A or 30B. Use of specimens other than
standard Alloy Grade 30A or 30B shall be noted in the test report.
NOTE 3—Where non-standard alloy is used, the standard flux shown in A1.1.5 may not be satisfactory. A low corrosive flux may be required.
6.1.5 Cast Aluminum, conforming to Alloy UNS A23190 (SAE 329). Specimen size, 50.850.8 mm by 25.425.4 mm by 3.18
mm [2(2 in. by 11 in. by ⁄8 in.].in.).
6.1.6 Cast Iron, conforming to Alloy UNS F10007 (SAE G3500). Specimen size, 50.850.8 mm by 25.425.4 mm by 3.18 mm
[2(2 in. by 11 in. by ⁄8 in.].in.).
6.2 Arrangement (See Fig. 2):
6.2.1 Metal Specimen Arrangement—None of the hardware used in metal specimen arrangement (metal specimen, screws,
washers, metal spacers, insulating sleeves, insulating spacers and nuts) can be reused for a test. The metal test specimens shall be
drilled through the center with a 6.75-mm [6.75 mm ( ⁄64-in.] in.) drill to accommodate a 50.8-mm [2-in.]50.8 mm (2 in.) 10–24
FIG. 2 Metal Specimen Arrangement
If a water bath is used, a significant reduction in evaporation rate is achieved by addition of floating plastic chips on the water surface.
Complete sets or individual metal test specimens are available from (a) Chemical Specialties Manufacturers Association, Inc., Suite 1120, 1001 Connecticut Ave., N.W.,
Washington, DC 20036; (b) Astro-Mechanics, Inc., 8500 Research Blvd., Austin, TX 78766; (c) The Metaspec Company, P.O. Box 27707, San Antonio, TX 78227; or (d)
Metal Samples Co. Inc., P.O. Box 8, Munford, AL 36268.
Unified Numbering System for Metals and Alloys, SAE-ASTM, July 1995.
D7935 − 20
brass machine screw covered with a thin-walled insulating sleeve. Polytetrafluoroethylene tubing with a 6.35-mm [6.35 mm
1 1 1
( ⁄4-in.] in.) outside diameter 1.59-mm [1.59 mm ( ⁄16-in.] in.) wide and a wall thickness of 0.4 mm [( ⁄64-in.] in.) is satisfactory.
Two half-hard brass legs shall be cut from 1.59-mm [1.59 mm ( ⁄16-in.] in.) sheet stock to size 50.850.8 mm by 25.4 mm [2(2 in.
1 1
by 1 in.].in.). A 6.35-mm [6.35 mm ( ⁄4-in.] in.) diameter hole shall be drilled in each leg with the center 6.35 mm [( ⁄4 in.]in.) from
the top and 12.7 mm [( ⁄2 in.]in.) from each side. The test “bundle” shall be made up on the insulated screw with the specimens
in the following order: brass leg, copper, solder, brass, steel, cast iron, cast aluminum, and brass leg. The specimens shall be
3 17
separated by 4.76-mm [4.76 mm ( ⁄16-in.] in.) thick solid metal spacers having a 6.75-mm [6.75 mm ( ⁄64-in.] in.) inside diameter
and a 11.11-mm [11.11 mm ( ⁄16-in.] in.] outside diameter. Insulating spacers made from polytetrafluoroethylene shall be used
between the brass legs and the specimen “bundle,” and between the brass and steel specimens. Brass spacers shall be used between
the brass, solder, and copper specimens, and steel spacers between the cast iron, steel, and cast aluminum specimens. The nut shall
be tightened firmly to ensure good electrical contact between the test specimens in each section of the “bundle.”
6.2.2 Alternate Metal Specimen Arrangement—When agreed upon between the supplier and the purchaser, an alternate metal
specimen arrangement may be used to evaluate multiple solder alloys, such as high lead Alloy Grade L50113 consisting of 97 %
lead, 2.5 % tin, 0.3 % silver, concurrently with Standard Alloy Grade 30A or 30B. It is recommended that the metal specimen
arrangement be modified by replacing the copper specimen with the high lead solder specimen and arranging specimens in the
bundle as follows:
High Lead Brass Alloy Grade Steel Cast Iron Cast
Solder 30A or 30B Aluminum
Use of alternate specimens and metal specimens arrangements shall be noted in the test report.
7. Preparation of Test Specimens
7.1 Sand the cast iron and cast aluminum specimens on the 25.425.4 mm by 50.8-mm [150.8 mm (1 in. by 2-in.]2 in.) cut
surfaces with “coarse” grade (No. 1) emery cloth. Remove any burrs from coupon edges and hole. Scrub all specimens vigorously,
using a moistened bristle brush and ground pumice powder or fine silicon carbide grit until the entire metal area is bright, shiny,
and free from any visible oxide film or tarnish.
7.2 Rinse the specimens thoroughly with tap water; then rinse with acetone, dry, and weigh to the nearest 1 mg. Cast aluminum
specimens should be dried in a 100°C100 °C oven for 1 h, to a constant weight, prior to recording the weight.
NOTE 4—If the test specimens are not to be used immediately, keep them in a desiccator until required.
8. Test Solutions
8.1 The concentration of the non-aqueous engine coolant to be tested shall be as follows:
8.1.1 Engine Coolant—The non-aqueous coolant shall be mixed with the proper quantity of corrosive water to give a test
solution containing a mixture of 94 volume % non-aqueous coolant with six volume % corrosive water.
8.1.2 Corrosive Water (Note 5)—The corrosive water shall contain 100 ppm each of sulfate, chloride, and bicarbonate ions
introduced as sodium salts.
8.2 Preparation of Sample—The preparation of the sample shall be done in accordance with Test Method Practice D1176,
except that the corrosive water shall be used for dilution instead of distilled water. Thus, any insoluble materials will be included
in the representative sample.
NOTE 5—The specified corrosive water can be prepared by dissolving the following amounts of anhydrous sodium salts in a quantity of distilled or
deionized water.
sodium sulfate 148 mg
sodium chloride 165 mg
sodium bicarbonate 138 mg
The resulting corrosive water solution should be made up to a volume of 1 L with distilled or deionized water at 20°C.20 °C.
8.2.1 If relatively large amounts of corrosive water are needed for testing, a concentrate may be prepared by dissolving ten times
the above amounts of the three chemicals, in distilled or deionized water, and adjusting the total volume to 1 L by further additions
of distilled or deionized water. When needed, the water concentrate is diluted to the ratio of one part by volume of concentrate
to nine parts of distilled or deionized water.
9. Test Conditions
9.1 Beaker Assembly—The arrangement of the assembled metal specimens with relation to the aerator tube and other
components is shown in Fig. 1. Note that the tip of the condenser just emerges from the bottom of the rubber stopper.
9.2 Test Temperature—The test solution shall be maintained at a temperature of 9696 °C 6 2°C [2052 °C (205 °F 6 5°F].4 °F).
9.3 Aeration Rate—The aeration rate shall be 100100 mL ⁄min 6 1010 mL mL/min. ⁄min. The aerator tube should be located
at least 12.7 mm [( ⁄2 in.]in.) away from the test “bundle” to avoid direct contact with the metal specimens.
9.4 Test Duration—The test shall be run continuously for 2 weeks (336 h).
D7935 − 20
10. Procedure
10.1 Make triplicate tests concurrently on each engine coolant solution in accordance with the following procedure:
10.1.1 Carefully clean the test beaker, condenser, rubber stopper, and aerator tube, and thoroughly rinse with water. Ensure all
components are dry before use.
10.1.2 Bolt the specimens together in the order given in 6.2 and place the “bundle” in the test beaker as shown in Fig. 1.
10.1.3 Pour 750 mL of the prepared test solution into the 1000-mL1000 mL beaker.
10.1.4 Fit the condenser and aeration tube to the beaker, and set the aeration rate at 100 mL/min, using a flow meter or other
suitable device.
10.1.5 Raise the temperature of the test solution to 96°C [205°F] for high-boiling engine coolants. 96 °C (205 °F). Pass water
through the condenser at a rate sufficient to maintain adequate cooling.
10.1.6 Check the tests once each working day to ensure proper solution temperature, aeration rate, and solution level. The tests
may operate unattended on weekends and holidays. Make up evaporation losses during the corrosion tests by addition of distilled
or deionized water.
10.1.7 At the end of the test, immediately disassemble specimens and brush very lightly with a soft bristle brush and water to
remove loosely held corrosion products. To remove the more tenacious corrosion products and films, the individual specimens shall
then be subjected to additional cleaning treatments as follows:
10.1.7.1 Iron and Steel—Remove adherent deposits by means of a brass scraper or brass bristle brush, followed by scrubbing
with a wet bristle brush and fine pumice to clean the specimen completely.
10.1.7.2 Copper and Brass—Dip in a 1 + 1 mixture of concentrated HCl (sp gr 1.19) and water for 15 s to remove tarnish films,
rinse with tap water to remove acid, and scrub with a wet bristle brush and
...