ASTM D6794-20e1

Standard Test Method for Measuring the Effect on Filterability of Engine Oils After Treatment with Various Amounts of Water and a Long (6 h) Heating Time

SIGNIFICANCE AND USE
5.1 It is normal for some of the combustion products of an internal combustion engine to penetrate into the engine lubricant and be retained in it.  
5.2 When an engine is run for a period of time and then stored over a long period of time, the by-products of combustion might be retained in the oil in a liquefied state.  
5.3 Under these circumstances, precipitates can form that impair the filterability of the oil the next time the engine is run.  
5.4 This test method subjects the test oil and the new oil to the same treatments such that the loss of filterability can be determined. The four water treatment levels may be tested individually, all four simultaneously, or any combination of multiple water treatment levels.  
5.5 Reference oils, on which the data obtained by this test method is known, are available.  
5.6 This test method requires that a reference oil also be tested and results reported. Two oils are available, one known to give a low and one known to give a high data value for this test method.
Note 1: When the new oil test results are to be offered as candidate oil test results for a specification, such as Specification D4485, the specification will state maximum allowable loss of filterability (flow reduction) of the test oil as compared to the new oil.
SCOPE
1.1 This test method covers the determination of the tendency of an oil to form a precipitate that can plug an oil filter. It simulates a problem that may be encountered in a new engine run for a short period of time, followed by a long period of storage with some water in the oil.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.  
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: 30-Apr-2020
• ICS: 75.100 - Lubricants, industrial oils and related products
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.B0 - Automotive Lubricants

Relations

• Refers: ASTM D4485-18 - Standard Specification for Performance of Active API Service Category Engine Oils
• Effective Date: 01-Jul-2018
• Refers: ASTM D4485-16 - Standard Specification for Performance of Active API Service Category Engine Oils
• Effective Date: 15-Dec-2016
• Refers: ASTM D4485-15a - Standard Specification for Performance of Active API Service Category Engine Oils
• Effective Date: 15-Apr-2015
• Refers: ASTM D4485-15 - Standard Specification for Performance of Active API Service Category Engine Oils
• Effective Date: 01-Apr-2015
• Refers: ASTM D4485-14 - Standard Specification for Performance of Active API Service Category Engine Oils
• Effective Date: 01-Dec-2014
• Refers: ASTM D4485-11b - Standard Specification for Performance of Active API Service Category Engine Oils
• Effective Date: 01-Oct-2011
• Refers: ASTM D4485-11a - Standard Specification for Performance of Active API Service Category Engine Oils
• Effective Date: 01-Jul-2011
• Refers: ASTM D4057-06(2011) - Standard Practice for Manual Sampling of Petroleum and Petroleum Products
• Effective Date: 01-Jun-2011
• Refers: ASTM D4485-11 - Standard Specification for Performance of Engine Oils
• Effective Date: 01-May-2011
• Refers: ASTM D4485-10a - Standard Specification for Performance of Engine Oils
• Effective Date: 01-Jul-2010
• Refers: ASTM D4485-10 - Standard Specification for Performance of Engine Oils
• Effective Date: 01-May-2010
• Refers: ASTM D4485-09 - Standard Specification for Performance of Engine Oils
• Effective Date: 15-Apr-2009
• Refers: ASTM D5862-09 - Standard Test Method for Evaluation of Engine Oils in Two-Stroke Cycle Turbo-Supercharged 6V92TA Diesel Engine (Withdrawn 2009)
• Effective Date: 15-Apr-2009
• Refers: ASTM D4485-07a - Standard Specification for Performance of Engine Oils
• Effective Date: 01-Dec-2007
• Refers: ASTM D4485-07 - Standard Specification for Performance of Engine Oils
• Effective Date: 01-May-2007

Overview

ASTM D6794-20e1 is a standardized test method developed by ASTM International for evaluating the effect of water contamination and extended heating on the filterability of engine oils. This method simulates conditions where engine oils may be exposed to water and prolonged storage after short engine operation, which can lead to the formation of precipitates capable of clogging oil filters. The procedure is essential for manufacturers, formulators, and quality assurance personnel involved in the production and performance assessment of engine lubricants.

Key Topics

• Purpose: Determines the tendency of engine oils to form precipitates after exposure to various water levels and a long (6-hour) heating period.
• Scope: Simulates real-world engine conditions, particularly relevant for engines run briefly and then stored with possible water contamination in the oil.
• Methodology: Involves mixing defined amounts of water with test oil, heating the mixture, cooling, and then measuring oil flow through a filter to assess filterability.
• Water Treatment Levels: Test is conducted at several levels - typically 0.6%, 1.0%, 2.0%, and 3.0% water in oil.
• Reference and Candidate Oils: Requires parallel testing with known reference oils, allowing for calibration and benchmarking against established performance criteria.
• Reporting: Results are reported as percent change in oil flow rate, with acceptance criteria established for performance.

Applications

The ASTM D6794-20e1 standard is invaluable for a variety of industrial, research, and regulatory contexts, including:

• Engine Oil Development: Enables formulators to assess whether new or reformulated engine oils maintain adequate filterability after exposure to water and heat, helping to prevent issues with filter plugging in real-world use.
• Quality Control: Used by lubricant manufacturers and suppliers to ensure that production batches of engine oils meet performance specifications regarding filterability after water contamination and storage.
• Specification Compliance: Supports compliance with industry standards such as API engine oil standards (e.g., ASTM D4485), which may reference allowable filterability loss as measured by this method.
• Research and Benchmarking: Provides a reliable, repeatable test for comparing experimental oil blends or evaluating the impact of additive packages designed to improve water tolerance and long-term storage stability.
• Regulatory and Certification Testing: Laboratories may use this standard in conjunction with ASTM Test Monitoring Center (TMC) reference oils to qualify oils for industry certifications.

Related Standards

• ASTM D1193: Specification for reagent water, used in the preparation of test solutions.
• ASTM D4057: Practice for manual sampling of petroleum and petroleum products.
• ASTM D4485: Specification for performance of active API service category engine oils, which can reference this method for filterability requirements.
• ASTM D5844/D5862 (Withdrawn): Other test methods for evaluating engine oil performance.
• ASTM TMC Protocols: Guidelines for using reference oils and calibration of laboratory equipment for enhanced consistency across labs.

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Keywords: engine oil filterability, ASTM D6794-20e1, water contamination, oil precipitate, engine oil storage, filter plugging, oil quality control, lubricants standard, reference oil testing, oil filterability test method.

By following ASTM D6794-20e1, oil formulators and quality managers can ensure engine oils meet critical filterability criteria, supporting reliable engine performance and compliance with industry requirements.

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.
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Designation: D6794 − 20
Standard Test Method for
Measuring the Effect on Filterability of Engine Oils After
Treatment with Various Amounts of Water and a Long (6 h)
Heating Time
This standard is issued under the fixed designation D6794; 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.
ε NOTE—Editorially updated TMC governance information in June 2022.
INTRODUCTION
Portions of this test method are written for use by laboratories that make use of ASTM Test
Monitoring Center (TMC) services (see Annex A1).
TheTMC provides reference oils, and engineering and statistical services to laboratories that desire
to produce test results that are statistically similar to those produced by laboratories previously
calibrated by the TMC.
In general, the Test Purchaser decides if a calibrated test stand is to be used. Organizations such as
theAmerican Chemistry Council require that a laboratory utilize theTMC services as part of their test
registration process. In addition, the American Petroleum Institute and the Gear Lubricant Review
Committee of the Lubricant Review Institute (SAE International) require that a laboratory use the
TMC services in seeking qualification of oils against their specifications.
The advantage of using the TMC services to calibrate test stands is that the test laboratory (and
hence the Test Purchaser) has an assurance that the test stand was operating at the proper level of test
severity. It should also be borne in mind that results obtained in a non-calibrated test stand may not
be the same as those obtained in a test stand participating in the ASTM TMC services process.
Laboratories that choose not to use the TMC services may simply disregard these portions.
ASTM International policy is to encourage the development of test procedures based on generic
equipment. It is recognized that there are occasions where critical/sole-source equipment has been
approved by the technical committee (surveillance panel/task force) and is required by the test
procedure. The technical committee that oversees the test procedure is encouraged to clearly identify
if the part is considered critical in the test procedure. If a part is deemed to be critical, ASTM
encourages alternative suppliers to be given the opportunity for consideration of supplying the critical
part/component providing they meet the approval process set forth by the technical committee.
An alternative supplier can start the process by initiating contact with the technical committee
(current chairs shown on ASTM TMC website). The supplier should advise on the details of the part
that is intended to be supplied. The technical committee will review the request and determine
feasibility of an alternative supplier for the requested replacement critical part. In the event that a
replacement critical part has been identified and proven equivalent, the sole-source supplier footnote
shall be removed from the test procedure.
For other information, refer to the research report of this test method.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of ASTMTestMonitoringCenter,203ArmstrongDrive,Freeport,PA16229.This
Subcommittee D02.B0 on Automotive Lubricants. test method is supplemented by Information Letters and Memoranda issued by the
Current edition approved May 1, 2020. Published May 2020. Originally ASTM Test Monitoring Center. This edition includes all information letters through
approved in 2002. Last previous edition approved in 2019 as D6794 – 19. DOI: No. 19-2. Users of this test method can contact the ASTM Test Monitoring Center
10.1520/D6794-20E01. to obtain the most recent of these.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6794 − 20
1. Scope* 3.1.3.1 Discussion—It may contain additives to enhance
certain properties. Inhibition of engine rusting, deposit
1.1 This test method covers the determination of the ten-
formation, valve train wear, oil oxidation, and foaming are
dency of an oil to form a precipitate that can plug an oil filter.
examples.
Itsimulatesaproblemthatmaybeencounteredinanewengine
3.1.4 engine oil, n—a liquid that reduces friction or wear, or
run for a short period of time, followed by a long period of
both, between the moving parts within an engine; removes
storage with some water in the oil.
heat, particularly from the underside of pistons; and serves as
1.2 The values stated in SI units are to be regarded as
a combustion gas sealant for the piston rings.
standard. No other units of measurement are included in this
3.1.4.1 Discussion—It may contain additives to enhance
standard.
certain properties. Inhibition of engine rusting, deposit
1.3 This standard does not purport to address all of the formation, valve train wear, oil oxidation, and foaming are
safety concerns, if any, associated with its use. It is the
examples. D5862
responsibility of the user of this standard to establish appro-
3.1.5 non-reference oil, n—any oil other than a reference
priate safety, health, and environmental practices and deter-
oil–such as a research formulation, commercial oil, or candi-
mine the applicability of regulatory limitations prior to use.
date oil.
1.4 This international standard was developed in accor-
3.1.5.1 Discussion—Reference oils are used to calibrate
dance with internationally recognized principles on standard-
testing facilities, to compare the performance of other oils, or
ization established in the Decision on Principles for the
to evaluate other materials (such as seals) that interact with
Development of International Standards, Guides and Recom-
oils.
mendations issued by the World Trade Organization Technical
3.1.6 reference oil, n—an oil of known performance
Barriers to Trade (TBT) Committee.
characteristics, used as a basis for comparison.
2. Referenced Documents 3.1.6.1 Discussion—Reference oils are used to calibrate
4 testing facilities, to compare the performance of other oils, or
2.1 ASTM Standards:
to evaluate other materials (such as seals) that interact with
D1193 Specification for Reagent Water
oils. D5844
D4057 Practice for Manual Sampling of Petroleum and
Petroleum Products 3.2 Definitions of Terms Specific to This Standard:
D4485 Specification for Performance of Active API Service 3.2.1 effective filter area, n—that surface of a test filter that
Category Engine Oils can receive the material to be filtered.
D5844 Test Method for Evaluation of Automotive Engine
3.2.2 new oil, n—an unused oil having the identical formu-
Oils for Inhibition of Rusting (Sequence IID) (Withdrawn
lation and base stock as the test oil.
2003)
3.2.3 test oil, n—the new oil with various amounts of water
D5862 Test Method for Evaluation of Engine Oils in Two-
added.
Stroke Cycle Turbo-Supercharged 6V92TADiesel Engine
3.2.3.1 Discussion—A potential precipitate in the test oil is
(Withdrawn 2009)
induced by heating the oil and aging.
3. Terminology
4. Summary of Test Method
3.1 Definitions:
4.1 Add deionized water to the test oil for a final solution of
3.1.1 calibrate, v—todeterminetheindicationoroutputofa
0.6 %, 1.0 %, 2.0 %, or 3.0 % water in oil. The sample is
device (e.g., thermometer, manometer, engine) with respect to
heated to 70 °C for 6 h, followed by storage at room tempera-
that of a standard.
ture. The sample is filtered and the flow rate is calculated
3.1.2 calibrationtest,n—atest,usingacodedoil,conducted
determining the engine oil filterability characteristics.
as specified in the test method.
5. Significance and Use
3.1.2.1 Discussion—The test result is used to determine the
suitability of the testing facility/laboratory to conduct such
5.1 It is normal for some of the combustion products of an
tests on non-reference oils.
internal combustion engine to penetrate into the engine lubri-
cant and be retained in it.
3.1.3 candidate oil, n—an oil that is intended to have the
performance characteristics necessary to satisfy a specification
5.2 When an engine is run for a period of time and then
and is tested against that specification.
stored over a long period of time, the by-products of combus-
tion might be retained in the oil in a liquefied state.
5.3 Under these circumstances, precipitates can form that
Supporting data have been filed at ASTM International Headquarters and may
beobtainedbyrequestingResearchReportRR:D02-1492.ContactASTMCustomer
impair the filterability of the oil the next time the engine is run.
Service at [e-mail].
5.4 This test method subjects the test oil and the new oil to
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
the same treatments such that the loss of filterability can be
Standards volume information, refer to the standard’s Document Summary page on
determined. The four water treatment levels may be tested
the ASTM website.
individually, all four simultaneously, or any combination of
The last approved version of this historical standard is referenced on
www.astm.org. multiple water treatment levels.
´1
D6794 − 20
5.5 Reference oils, on which the data obtained by this test 6.1.4 Automotive Oil Filter Paper, 25 µm porosity.
method is known, are available.
6.2 Blender, capable of 18 000 r/min 610 % without the
container.
5.6 This test method requires that a reference oil also be
tested and results reported. Two oils are available, one known
6.3 Timer, capable of timing 30 s 61s.
to give a low and one known to give a high data value for this
6.4 Container, 250 mL, with blade compatible with the
test method.
blender.
NOTE 1—When the new oil test results are to be offered as candidate oil
test results for a specification, such as Specification D4485, the specifi- 6.5 Syringe, 1000 µL.
cation will state maximum allowable loss of filterability (flow reduction)
6.6 Glass Jars, 60 mL, wide-mouth with inert lined lids.
of the test oil as compared to the new oil.
NOTE 2—Paperbacked lids may detach from lid and are not suggested
6. Apparatus for use.
6.7 Mechanical Convection Oven, capable of maintaining
6.1 The apparatus consists of a 25 mLburette, a filter holder
70 °C 6 1 °C.
with 25 µm automotive oil filter paper, and a source of 69 kPa
6 2 kPa air pressure. Discs of filter paper are cut to fit the
6.8 Sensors (or equivalent timing devices), capable of mea-
holder and installed (see Fig. 1).
suring sequential events to 1 s resolution.
6.1.1 Burette (glass or plastic), 25 mL, with polytetrafluo-
6.9 Tubing, inert tubing used to connect to burette.
roethylene (PTFE) stopcock and (1.8 6 0.1) mm burette tip
opening.
The sole source of supply of the automotive oil filter paper known to the
6.1.2 Air Regulator, capable of regulating air to a pressure committee at this time is The Central Parts Distributor, OH Technologies Inc., P.O.
Box5039,Mentor,OH44061-5039.Ifyouareawareofalternativesuppliers,please
of (69 6 2) kPa.
provide this information toASTM International Headquarters. Your comments will
6.1.3 Filter Holder, with effective filter area approximately
receive careful consideration at a meeting of the responsible technical committee,
0.8 cm . which you may attend.
NOTE 1—Filter holder has approximate area of 0.8 cm . It contains automotive oil filter paper (25 µm porosity).
FIG. 1 Apparatus To Measure Engine Oil Filterability
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D6794 − 20
6.9.1 Air Regulator Tubing, flexible tubing to prevent air 10. Procedure
from leaking from the air supply to the burette.
6.9.2 Filter Holder Tubing, flexible tubing used to connect
TABLE 1 Test Oil and Water Sample Quantities, by Water Treat
burette tip to filter holder.
Rate
Treatment Rate Test Oil Deionized Water
7. Reagents
0.6% 49.7g±0.1g 0.3g±0.05g
1.0% 49.5g±0.1g 0.5g±0.05g
7.1 Purity of Reagents—Use reagent grade chemicals in all
2.0% 49.0g±0.1g 1.0g±0.05g
tests. Unless otherwise indicated, it is intended that all reagents 3.0% 48.5g±0.1g 1.5g±0.05g
shall conform to the specifications of the Committee on
AnalyticalReagentsoftheAmericanChemicalSociety, where
such specifications are available. Other grades may be used,
10.1 Assemble apparatus as shown in Fig. 1 with filter
provided it is first ascertained that the reagent is of sufficiently
installed in proper orientation (25 µm smooth side up).
high purity to permit its use without lessening the accuracy of
10.2 Determine the new oil flow rate by placing a sample of
the determination.
the new oil in the burette. Pressurize the system and force at
7.2 Purity of Water—Unless otherwise indicated, references
least10 mLofoilthroughthefiltertosaturatethefilterwithoil
to water shall be understood to mean Test Method D1193 Type
and remove any air bubbles. Disconnect the air line and fill the
III deionized water or water of equivalent purity.
burette with new oil to a level 1 cm to 2 cm above the 0 mark.
Pressurize the system to 69 kPa 6 2 kPa, open the stopcock,
7.3 TMC Reference Oils—These are available from the Test
and measure the flow time for each successive 5 mL of oil
Monitoring Center.
between the 0 mL and 25 mL graduations.
8. Sampling
10.3 Todeterminethetestoilflowrate,theflowtimesofthe
new oil are first determined. Using the same filter disc, filter
8.1 Take samples in accordance with the instructions in
holder,andburette,reducethenewoillevelintheburettetothe
Practice D4057.
lowest level that allows no air bubbles below the stopcock.
9. Preparation of Test Oil Sample and Filter Disconnect the air line and fill the burette with a well-mixed
sample of test oil to a level 1 cm to 2 cm above the 0 mark.
9.1 Determine the water treatment rate for the test and
Pressurize the system to 69 kPa 6 2 kPa, open the stopcock,
record it.Add the appropriate quantity of test oil and deionized
and measure the flow time for each successive 5 mL of oil
water (see Table 1) to the blender for the desired water
between the 0 mL and 25 mL graduations.
treatment rate, using the 1000 µL syringe.
10.4 Run each non-reference and reference oil in duplicate;
9.2 Mix test oil and water in the blender for 30 s 61sat
repeat Section 9 and 10.1 to 10.4 for each non-reference and
18 000 r⁄min 6 1800 r⁄min.
each reference oil.
9.3 Add 49.7 g 6 0.1 g of test oil, 0
...