ASTM D3306-21

Standard Specification for Glycol Base Engine Coolant for Automobile and Light-Duty Service

SCOPE
1.1 This specification covers the requirements for ethylene glycol or propylene glycol or ethylene glycol containing glycerin base engine coolants used in automobiles or other light-duty service cooling systems. When concentrates are used at 40 % to 60 % concentration (allowance to 70 % concentration agreement between manufacturer and user) by volume in water, or when prediluted glycol base engine coolants 50 volume % or higher engine coolant concentrate are used without further dilution, they will function effectively to provide protection against freezing, boiling, and corrosion.  
1.2 The coolants governed by this specification are categorized as follows:
Coolant Type  
Description  
I  
Ethylene glycol base concentrate  
II  
Propylene glycol base concentrate  
V  
Ethylene glycol base concentrate
containing glycerin  
III  
Ethylene glycol predilute 50 volume % or higher engine coolant concentrate  
IV  
Propylene glycol predilute 50 volume % or higher engine coolant concentrate  
VI  
Ethylene glycol base predilute
containing glycerin 50 volume % or higher engine coolant concentrate
Note 1: This specification is based on the knowledge of the performance of engine coolants prepared from new or virgin ingredients. This specification shall also apply to engine coolants prepared using glycol generated from recycled or reprocessed used coolant or reprocessed industrial-source glycol, provided that said glycol meets the requirements of Specification E1177. Separate specifications (D6471 and D6472) exist for engine coolants prepared from recycled or reprocessed used coolant or reprocessed industrial-source glycol that does not meet the requirements established in Specification E1177. This specification shall also apply to glycol based engine coolants prepared using fully refined glycerin provided that said glycerin meets the requirements for Specification D7640.  
1.3 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.  
1.4 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.
Note 2: This specification applies to glycol base engine coolant for automobiles and light-duty service. Specifications D4985 and D6210 exist for heavy duty engine service.  
1.5 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-Oct-2021
• ICS: 71.100.45 - Refrigerants and antifreezes
• Technical Committee: D15 - Engine Coolants and Related Fluids
• Drafting Committee: D15.07 - Specifications

Relations

• Refers: ASTM D1384-24 - Standard Test Method for Corrosion Test for Engine Coolants in Glassware
• Effective Date: 01-Jan-2024
• Refers: ASTM D5931-20 - Standard Test Method for Density and Relative Density of Engine Coolant Concentrates and Aqueous Engine Coolants by Digital Density Meter
• Effective Date: 15-May-2020
• Refers: ASTM D1287-11(2020) - Standard Test Method for pH of Engine Coolants and Antirusts
• Effective Date: 01-Jan-2020
• Refers: ASTM D1121-11(2020) - Standard Test Method for Reserve Alkalinity of Engine Coolants and Antirusts
• Effective Date: 01-Jan-2020
• Refers: ASTM E1177-19 - Standard Specification for Engine Coolant Grade Glycol
• 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 D4340-19 - Standard Test Method for Corrosion of Cast Aluminum Alloys in Engine Coolants Under Heat-Rejecting Conditions
• Effective Date: 01-May-2019
• Refers: ASTM D6130-11(2018) - Standard Test Method for Determination of Silicon and Other Elements in Engine Coolant by Inductively Coupled Plasma-Atomic Emission Spectroscopy
• Effective Date: 01-Mar-2018
• Refers: ASTM D5931-13(2017) - Standard Test Method for Density and Relative Density of Engine Coolant Concentrates and Aqueous Engine Coolants by Digital Density Meter
• Effective Date: 01-Nov-2017
• Refers: ASTM D1881-17 - Standard Test Method for Foaming Tendencies of Engine Coolants in Glassware
• Effective Date: 01-Nov-2017
• Refers: ASTM D1122-16(2017)e1 - Standard Test Method for Density or Relative Density of Engine Coolant Concentrates and Engine Coolants By The Hydrometer
• Effective Date: 01-Apr-2017
• Refers: ASTM D1122-16 - Standard Test Method for Density or Relative Density of Engine Coolant Concentrates and Engine Coolants By The Hydrometer
• Effective Date: 01-Apr-2016
• Refers: ASTM D1177-16 - Standard Test Method for Freezing Point of Aqueous Engine Coolants
• Effective Date: 01-Apr-2016
• Refers: ASTM D1120-16 - Standard Test Method for Boiling Point of Engine Coolants
• Effective Date: 01-Apr-2016
• Refers: ASTM E1177-14 - Standard Specification for Engine Coolant Grade Glycol
• Effective Date: 01-Nov-2014

Overview

ASTM D3306-21 sets the standard specification for glycol base engine coolant used in automobiles and light-duty service vehicles. This specification covers engine coolants formulated with ethylene glycol, propylene glycol, or ethylene glycol containing glycerin, used to protect engine cooling systems from freezing, boiling, and corrosion. The standard defines performance, physical, and chemical requirements to ensure coolants are effective and reliable when used as either concentrates (requiring dilution) or prediluted solutions.

Compliance with ASTM D3306-21 is essential for manufacturers, automotive service providers, and vehicle owners to maintain engine performance and prolong engine lifespan.

Key Topics

• Coolant Types: The specification addresses several coolant formulations:
  • Type I: Ethylene glycol base concentrate
  • Type II: Propylene glycol base concentrate
  • Type III: Ethylene glycol prediluted (50% or higher)
  • Type IV: Propylene glycol prediluted (50% or higher)
  • Type V: Ethylene glycol concentrate containing glycerin
  • Type VI: Ethylene glycol prediluted with glycerin (50% or higher)
• Performance Requirements: Coolants must provide effective protection against:
  • Freezing and Boiling: Maintaining performance across a wide range of temperatures
  • Corrosion: Inhibiting rust and corrosion in engine parts including aluminum, brass, copper, steel, and cast iron
  • Compatibility: No adverse effects on automotive finishes, nonmetals, or seals
• Concentration Guidelines: Concentrates are used at 40%-60% in water; prediluted coolants (minimum 50% concentrate) are used as-is, with some flexibility up to 70% concentration upon agreement between user and manufacturer.
• Ingredient Quality: Glycol must meet ASTM E1177 requirements; glycerin, if used, must meet ASTM D7640. Both new/virgin and approved recycled materials are permissible.
• Water Quality: Water used for dilution or formulation must meet specific criteria on chlorides, sulfates, hardness, pH, and iron to prevent deposition and corrosion.
• Testing Methods: Referenced ASTM test methods ensure standardized evaluation of properties like freezing point, boiling point, pH, reserve alkalinity, and foaming tendencies.

Applications

ASTM D3306-21 is applied in the formulation, production, and quality control of automotive engine coolants and antifreeze products. Key uses include:

• Manufacturers: Developing glycol-based coolant products for the automotive and light vehicle marketplace in compliance with safety and performance criteria.
• Service Centers and Dealers: Selecting and recommending appropriate coolants for passenger vehicles and light trucks to ensure warranty compliance and optimal engine protection.
• Fleet Operators and Maintenance Teams: Implementing coolant management practices, including routine inspections, proper mixing with qualified water sources, and adhering to recommended replacement intervals.
• End-Users (Vehicle Owners): Ensuring the use of approved coolants for maintenance and refills, helping prevent engine overheating, corrosion, and freeze-ups.

Related Standards

For a comprehensive approach to engine coolant quality and management, the following ASTM standards are commonly referenced alongside ASTM D3306-21:

• ASTM E1177 - Specification for engine coolant grade glycol
• ASTM D7640 - Specification for engine coolant grade glycerin
• ASTM D4985 - Specification for low silicate ethylene glycol base engine coolant (for heavy-duty engines)
• ASTM D6210 - Specification for fully-formulated glycol base engine coolant (for heavy-duty engines)
• ASTM D6471 & D6472 - Specifications for recycled glycol base engine coolant concentrates and prediluted products (for specific requirements)
• ASTM D1120, D1177, D1287, D1384, D2809 - Methods for testing boiling point, freezing point, pH, and corrosion performance

Adhering to ASTM D3306-21 ensures coolant products deliver dependable performance and protection while aligning with the latest industry standards for automotive and light-duty vehicles.

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:D3306 −21
Standard Specification for
Glycol Base Engine Coolant for Automobile and Light-Duty
Service
This standard is issued under the fixed designation D3306; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 1.3 The values stated in SI units are to be regarded as
standard. The values given in parentheses after SI units are
1.1 This specification covers the requirements for ethylene
providedforinformationonlyandarenotconsideredstandard.
glycol or propylene glycol or ethylene glycol containing
1.4 This standard does not purport to address all of the
glycerin base engine coolants used in automobiles or other
safety concerns, if any, associated with its use. It is the
light-dutyservicecoolingsystems.Whenconcentratesareused
responsibility of the user of this standard to establish appro-
at 40% to 60% concentration (allowance to 70% concentra-
priate safety, health, and environmental practices and deter-
tion agreement between manufacturer and user) by volume in
mine the applicability of regulatory limitations prior to use.
water, or when prediluted glycol base engine coolants 50
volume % or higher engine coolant concentrate are used
NOTE 2—This specification applies to glycol base engine coolant for
automobilesandlight-dutyservice.SpecificationsD4985andD6210exist
without further dilution, they will function effectively to
for heavy duty engine service.
provide protection against freezing, boiling, and corrosion.
1.5 This international standard was developed in accor-
1.2 The coolants governed by this specification are catego-
dance with internationally recognized principles on standard-
rized as follows:
ization established in the Decision on Principles for the
Coolant Type Description
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
I Ethylene glycol base concentrate
II Propylene glycol base concentrate Barriers to Trade (TBT) Committee.
V Ethylene glycol base concentrate
containing glycerin
2. Referenced Documents
III Ethylene glycol predilute 50 volume % or higher
2.1 ASTM Standards:
engine coolant concentrate
D512Test Methods for Chloride Ion In Water (Withdrawn
IV Propylene glycol predilute 50 volume % or higher
2021)
engine coolant concentrate
VI Ethylene glycol base predilute
D516Test Method for Sulfate Ion in Water
containing glycerin 50 volume % or higher engine
D1119Test Method for Percent Ash Content of Engine
coolant concentrate
Coolants
NOTE 1—This specification is based on the knowledge of the perfor-
D1120Test Method for Boiling Point of Engine Coolants
mance of engine coolants prepared from new or virgin ingredients. This
D1121Test Method for ReserveAlkalinity of Engine Cool-
specification shall also apply to engine coolants prepared using glycol
ants and Antirusts
generated from recycled or reprocessed used coolant or reprocessed
D1122Test Method for Density or Relative Density of
industrial-source glycol, provided that said glycol meets the requirements
of Specification E1177. Separate specifications (D6471 and D6472) exist EngineCoolantConcentratesandEngineCoolantsByThe
forenginecoolantspreparedfromrecycledorreprocessedusedcoolantor
Hydrometer
reprocessed industrial-source glycol that does not meet the requirements
D1123Test Methods for Water in Engine Coolant Concen-
established in Specification E1177. This specification shall also apply to
trate by the Karl Fischer Reagent Method
glycol based engine coolants prepared using fully refined glycerin
D1126Test Method for Hardness in Water
provided that said glycerin meets the requirements for Specification
D7640. D1177Test Method for Freezing Point of Aqueous Engine
Coolants
1 2
ThisspecificationisunderthejurisdictionofASTMCommitteeD15onEngine For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Coolants and Related Fluids and is the direct responsibility of Subcommittee contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
D15.07 on Specifications. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Nov. 1, 2021. Published November 2021. Originally the ASTM website.
approved in 1974. Last previous edition approved in 2020 as D3306–20. DOI: The last approved version of this historical standard is referenced on
10.1520/D3306-21. www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3306−21
D1287TestMethodforpHofEngineCoolantsandAntirusts 3. Terminology
D1293Test Methods for pH of Water
3.1 Definitions of Terms Specific to This Standard:
D1384Test Method for Corrosion Test for Engine Coolants
3.1.1 glycerin, n—Specification D7640 grade glycerin for
in Glassware
engine coolant.
D1881Test Method for Foaming Tendencies of Engine
3.1.2 other glycols, n—in ethylene glycol base engine
Coolants in Glassware
coolant, diethylene glycol, triethylene glycol, tetraethylene
D1882Test Method for Effect of Cooling System Chemical
glycol, propylene glycol, dipropylene glycol, tripropylene
Solutions on Organic Finishes for Automotive Vehicles
glycol, and 1,3-propanediol.
D2570TestMethodforSimulatedServiceCorrosionTesting
3.1.3 other glycols, n—in propylene glycol base engine
of Engine Coolants
coolant, ethylene glycol, diethylene glycol, triethylene glycol,
D2809Test Method for Cavitation Corrosion and Erosion-
tetraethylene glycol, dipropylene glycol, tripropylene glycol,
Corrosion Characteristics of Aluminum Pumps With En-
and 1,3-propanediol.
gine Coolants
D3321Test Method for Use of the Refractometer for Field
3.2 For definitions of other terms used in this specification,
Test Determination of the Freezing Point of Aqueous
refer to Terminology D4725.
Engine Coolants
4. General Requirements
D3634Test Method for Trace Chloride Ion in Engine Cool-
ants
4.1 Engine coolant concentrates or prediluted glycol base
D4327Test Method forAnions in Water by Suppressed Ion enginecoolantsshallbeformulatedwitheitherethyleneglycol
Chromatography
or propylene glycol meeting Specification E1177, water, and
D4340TestMethodforCorrosionofCastAluminumAlloys shall contain suitable corrosion inhibitors, dye, and a foam
in Engine Coolants Under Heat-Rejecting Conditions
suppressor.
D4725TerminologyforEngineCoolantsandRelatedFluids
4.2 Ethylene glycol base engine coolant concentrates (Type
D4985Specification for Low Silicate Ethylene Glycol Base
I) may contain a maximum of 15% other glycols, as long as
Engine Coolant for Heavy Duty Engines Requiring a
the physical, chemical, and performance requirements of this
Pre-Charge of Supplemental Coolant Additive (SCA)
specification can be met. Similarly, prediluted ethylene glycol
D5827Test Method for Analysis of Engine Coolant for
base coolants (Type III) may contain a maximum of 7.5%
Chloride and Other Anions by Ion Chromatography
other glycols as long as all of the requirements of this
D5931Test Method for Density and Relative Density of
specification can be met.
Engine Coolant Concentrates and Aqueous Engine Cool-
4.3 Propylene glycol base engine coolant concentrates
ants by Digital Density Meter
(Type II) may contain a combined maximum of 1% other
D6130Test Method for Determination of Silicon and Other
glycols (less than 0.5% for prediluted propylene glycol base
Elements in Engine Coolant by Inductively Coupled
coolants, Type IV) and all of the physical, chemical, and
Plasma-Atomic Emission Spectroscopy
performance requirements of this specification must be met.
D6210Specification for Fully-Formulated Glycol Base En-
gine Coolant for Heavy-Duty Engines 4.4 Ethyleneglycolbasecoolantconcentrates(TypeV)may
D6471Specification for Recycled Prediluted Aqueous Gly-
contain glycerin as long as the physical, chemical and perfor-
col Base Engine Coolant (50 Volume % Minimum) for mance requirements of this specification can be met. Glycerin
Automobile and Light-Duty Service (Withdrawn 2019)
blended into Type V coolant concentrates shall be in accor-
D6472SpecificationforRecycledGlycolBaseEngineCool- dance with Specification D7640.
ant Concentrate for Automobile and Light-Duty Service
4.5 All engine coolant concentrates or prediluted glycol
(Withdrawn 2019)
baseenginecoolantsshallconformtothegeneralrequirements
D6660Test MethodforFreezingPointofAqueous Ethylene
given in Table 1.
Glycol Base Engine Coolants by Automatic Phase Tran-
4.6 Prediluted glycol base engine coolants shall be formu-
sition Method
lated using water that meets the following requirements:
D7640Specification for Engine Coolant Grade Glycerin
Property Specific Values ASTM Test Method
E29Practice for Using Significant Digits in Test Data to
Determine Conformance with Specifications
Chlorides, µg/g (ppm) 25 max D5827, D512,
E394Test Method for Iron in Trace Quantities Using the
D4327
Sulfate, µg/g (ppm) 50 max D5827, D516,
1,10-Phenanthroline Method
D4327
E1177Specification for Engine Coolant Grade Glycol
Hardness, as CaCO , µg/g (ppm) 20 max D6130, D1126
pH 5.5 to 8.5 D1287, D1293
2.2 Other Document:
Iron, µg/g (ppm) 1.0 max D6130, E394
Federal Method 2540BTotal Dissolved Solids Dried at
103–105°C
TABLE 1 General Requirements
Property Specified ASTM
Values Test Method
Standard Methods for the Examination of Water and Wastewater. American
Color Distinctive . . .
Public Health Association, et al, 800 I Street, NW, Washington, DC 20001, Effect on nonmetals No adverse effect Under consideration
http://www.apha.org.
D3306−21
5.2 The requirements listed in Table 2 and Table 3 for
NOTE 3—Prediluted coolants are intended for direct addition to an
prediluted coolants (Types III, IV, and VI) are prescribed for
enginecoolingsystemwithnofurtherdilution.However,ifcircumstances
thecoolantaspackaged,withoutfurtherdilutionoradjustment.
require addition and prediluted aqueous engine coolant is not available,
usetheappropriateenginecoolantconcentrate(TypeI,II,orV)dilutedto
5.3 All coolant concentrates and prediluted coolants shall
50 volume % with water of at least the quality outlined in Table X1.1.
conform to the performance requirements listed in Table 4.
4.7 When diluting engine coolant concentrates for actual
5.4 Coolant concentrates shall be diluted for performance
service, use deionized (demineralized) or distilled water, mu-
testing as described in the individual ASTM test methods.
nicipal(treated)water,oralowmineralcontentwellwater(see
Appendix X1, Table X1.1). This procedure will minimize the
5.5 If the freezing point of the prediluted product is below
formation of hard water scale and avoid the introduction of
–36.4°C(forTypeIIIandVI)or–31.0°C(forTypeIV)adjust
mineral components, such as chlorides and sulfates, which can
with deionized water before proceeding with performance
increase the corrosion rate of aluminum and iron.
testing. The freezing point of prediluted ethylene glycol base
4.8 Wheninstalledinaccordancewiththevehiclemanufac-
coolants (Type III) and prediluted ethylene glycol base cool-
turer’srecommendationsandthoseontheproductlabel,engine
ants containing glycerin (Type VI) shall be −36.4 °C
coolant concentrates or prediluted glycol base engine coolants
(−33.5°F) and that of prediluted propylene glycol base cool-
shall be suitable for use in a properly maintained cooling
ants (Type IV) shall be –31.0°C (–23.8°F).
system (Appendix X1) in normal light-duty service for a
5.6 Adjusted, prediluted engine coolant performance test
minimum of one year without adversely affecting fluid flow
solutions shall be prepared as described in Table 4, Footnotes
and heat transfer.
B through F.
5. Detailed Requirements
6. Keywords
5.1 Glycol base coolant concentrates and prediluted cool-
6.1 engine coolant; engine coolant concentrate; ethylene
ants shall conform to the physical and chemical requirements
prescribed in Table 2 and Table 3 depending on coolant type glycol; glycerine; glycerol; light-duty engine coolant; predi-
luted engine coolant; propylene glycol; 1,2,3-propanediol
(see 1.2).
TABLE 2 Physical and Chemical Requirements for Concentrates
Property Type I Type II Type V ASTM Test Method
A
Relative density 1.110 to 1.145 1.030 to 1.065 1.110 to 1.160 D1122, D5931
15.6/15.6 °C (60 ⁄60 °F)
B,C
Freezing point, °C (°F), −36.4 (−33.5) max −31.0 (−23.8) max −36.4 (−33.5) max D1177, D6660
50 vol % in DI water
B,D
Boiling point, °C (°F),
108 (226) min 104 (219) min 108 (226) min
50 vol % in DI water
Undiluted 163 (325) min 152 (305) min 163 (325 min) D1120
Ash content, mass % 5 max 5 max 5 max D1119
pH, 50 vol % in DI water 7.5 to 11.0 7.5 to 11.0 7.5 to 11.0 D1287
E
Chloride, µg/g 25 max 25 max 25 max D3634, D5827
Water, mass % report report report D1123
F F F
Reserve alkalinity, mL report report report D1121
G
Effect on automotive finish no effect no effect no effect D1882
(use clear coat thermoset
urethane or acrylic urethane finish)
A
Type V engine coolant is ethylene glycol base containing glycerin. Other ingredients that do not meet Specifications E1177 and D7640 shall not be substituted in this
blend.
B
For purposes of determining conformance with this specification, an observed value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing
the specification lim
...

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: D3306 − 20 D3306 − 21
Standard Specification for
Glycol Base Engine Coolant for Automobile and Light-Duty
Service
This standard is issued under the fixed designation D3306; 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 specification covers the requirements for ethylene glycol or propylene glycol or ethylene glycol containing glycerin base
engine coolants used in automobiles or other light duty light-duty service cooling systems. When concentrates are used at 40 to
70 % concentration 40 % to 60 % concentration (allowance to 70 % concentration agreement between manufacturer and user) by
volume in water, or when prediluted glycol base engine coolants 50 volume % or higher engine coolant concentrate are used
without further dilution, they will function effectively to provide protection against freezing, boiling, and corrosion.
1.2 The coolants governed by this specification are categorized as follows:
Coolant Type Description
I Ethylene glycol base concentrate
II Propylene glycol base concentrate
V Ethylene glycol base concentrate
containing glycerin
III Ethylene glycol predilute 50 volume % or higher
engine coolant concentrate
IV Propylene glycol predilute 50 volume % or higher
engine coolant concentrate
VI Ethylene glycol base predilute
containing glycerin 50 volume % or higher engine
coolant concentrate
NOTE 1—This specification is based on the knowledge of the performance of engine coolants prepared from new or virgin ingredients. This specification
shall also apply to engine coolants prepared using glycol generated from recycled or reprocessed used coolant or reprocessed industrial-source glycol,
provided that said glycol meets the requirements of Specification E1177. Separate specifications (D6471 and D6472) exist for engine coolants prepared
from recycled or reprocessed used coolant or reprocessed industrial-source glycol that does not meet the requirements established in Specification E1177.
This specification shall also apply to glycol based engine coolants prepared using fully refined glycerin provided that said glycerin meets the requirements
for Specification D7640.
1.3 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.
1.4 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.
This specification is under the jurisdiction of ASTM Committee D15 on Engine Coolants and Related Fluids and is the direct responsibility of Subcommittee D15.07
on Specifications.
Current edition approved May 15, 2020Nov. 1, 2021. Published June 2020November 2021. Originally approved in 1974. Last previous edition approved in 20192020 as
D3306–19.–20. DOI: 10.1520/D3306-20.10.1520/D3306-21.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3306 − 21
NOTE 2—This specification applies to glycol base engine coolant for automobiles and light duty light-duty service. Specifications D4985 and D6210 exist
for heavy duty engine service.
1.5 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:
D512 Test Methods for Chloride Ion In Water (Withdrawn 2021)
D516 Test Method for Sulfate Ion in Water
D1119 Test Method for Percent Ash Content of Engine Coolants
D1120 Test Method for Boiling Point of Engine Coolants
D1121 Test Method for Reserve Alkalinity of Engine Coolants and Antirusts
D1122 Test Method for Density or Relative Density of Engine Coolant Concentrates and Engine Coolants By The Hydrometer
D1123 Test Methods for Water in Engine Coolant Concentrate by the Karl Fischer Reagent Method
D1126 Test Method for Hardness in Water
D1177 Test Method for Freezing Point of Aqueous Engine Coolants
D1287 Test Method for pH of Engine Coolants and Antirusts
D1293 Test Methods for pH of Water
D1384 Test Method for Corrosion Test for Engine Coolants in Glassware
D1881 Test Method for Foaming Tendencies of Engine Coolants in Glassware
D1882 Test Method for Effect of Cooling System Chemical Solutions on Organic Finishes for Automotive Vehicles
D2570 Test Method for Simulated Service Corrosion Testing of Engine Coolants
D2809 Test Method for Cavitation Corrosion and Erosion-Corrosion Characteristics of Aluminum Pumps With Engine Coolants
D3321 Test Method for Use of the Refractometer for Field Test Determination of the Freezing Point of Aqueous Engine Coolants
D3634 Test Method for Trace Chloride Ion in Engine Coolants
D4327 Test Method for Anions in Water by Suppressed Ion Chromatography
D4340 Test Method for Corrosion of Cast Aluminum Alloys in Engine Coolants Under Heat-Rejecting Conditions
D4725 Terminology for Engine Coolants and Related Fluids
D4985 Specification for Low Silicate Ethylene Glycol Base Engine Coolant for Heavy Duty Engines Requiring a Pre-Charge
of Supplemental Coolant Additive (SCA)
D5827 Test Method for Analysis of Engine Coolant for Chloride and Other Anions by Ion Chromatography
D5931 Test Method for Density and Relative Density of Engine Coolant Concentrates and Aqueous Engine Coolants by Digital
Density Meter
D6130 Test Method for Determination of Silicon and Other Elements in Engine Coolant by Inductively Coupled Plasma-Atomic
Emission Spectroscopy
D6210 Specification for Fully-Formulated Glycol Base Engine Coolant for Heavy-Duty Engines
D6471 Specification for Recycled Prediluted Aqueous Glycol Base Engine Coolant (50 Volume % Minimum) for Automobile
and Light-Duty Service (Withdrawn 2019)
D6472 Specification for Recycled Glycol Base Engine Coolant Concentrate for Automobile and Light-Duty Service (Withdrawn
2019)
D6660 Test Method for Freezing Point of Aqueous Ethylene Glycol Base Engine Coolants by Automatic Phase Transition
Method
D7640 Specification for Engine Coolant Grade Glycerin
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E394 Test Method for Iron in Trace Quantities Using the 1,10-Phenanthroline Method
E1177 Specification for Engine Coolant Grade Glycol
2.2 Other Document:
Federal Method 2540B Total Dissolved Solids Dried at 103–105°C
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 the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Standard Methods for the Examination of Water and Wastewater. American Public Health Association, et al, 800 I Street, NW, Washington, DC 20001,
http://www.apha.org.
D3306 − 21
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 glycerin—glycerin, n—Specification D7640 grade glycerin for engine coolant.
3.1.2 other glycols, n—in ethylene glycol base engine coolant, diethylene glycol, triethylene glycol, tetraethylene glycol,
propylene glycol, dipropylene glycol, tripropylene glycol, and 1,3-propanediol.
3.1.3 other glycols, n—in propylene glycol base engine coolant, ethylene glycol, diethylene glycol, triethylene glycol,
tetraethylene glycol, dipropylene glycol, tripropylene glycol, and 1,3-propanediol.
3.2 For definitions of other terms used in this specification, refer to Terminology D4725.
4. General Requirements
4.1 Engine coolant concentrates or prediluted glycol base engine coolants shall be formulated with either ethylene glycol or
propylene glycol meeting Specification E1177, water, and shall contain suitable corrosion inhibitors, dye, and a foam suppressor.
4.2 Ethylene glycol base engine coolant concentrates (Type I) may contain a maximum of 15 % other glycols, as long as the
physical, chemical, and performance requirements of this specification can be met. Similarly, prediluted ethylene glycol base
coolants (Type III) may contain a maximum of 7.5 % other glycols as long as all of the requirements of this specification can be
met.
4.3 Propylene glycol base engine coolant concentrates (Type II) may contain a combined maximum of 1 % other glycols (less than
0.5 % for prediluted propylene glycol base coolants, Type IV) and all of the physical, chemical, and performance requirements of
this specification must be met.
4.4 Ethylene glycol base coolant concentrates (Type V) may contain glycerin as long as the physical, chemical and performance
requirements of this specification can be met. Glycerin blended into Type V coolant concentrates shall be in accordance with
Specification D7640.
4.5 All engine coolant concentrates or prediluted glycol base engine coolants shall conform to the general requirements given in
Table 1.
4.6 Prediluted glycol base engine coolants shall be formulated using water that meets the following requirements:
Property Specific Values ASTM Test Method
Chlorides, μg/g (ppm) 25 max D5827, D512,
D4327
Sulfate, μg/g (ppm) 50 max D5827, D516,
D4327
Hardness, as CaCO , μg/g (ppm) 20 max D6130, D1126
pH 5.5 to 8.5 D1287, D1293
Iron, μg/g (ppm) 1.0 max D6130, E394
TABLE 1 General Requirements
Property Specified ASTM
Values Test Method
Color Distinctive . . .
Effect on nonmetals No adverse effect Under consideration
D3306 − 21
TABLE 2 Physical and Chemical Requirements for Concentrates
Property Type I Type II Type V ASTM Test Method
A
Relative density 1.110 to 1.145 1.030 to 1.065 1.110 to 1.160 D1122, D5931
15.6/15.6 °C (60 ⁄60 °F)
B,C
Freezing point, °C (°F), −36.4 (−33.5) max −31.0 (−23.8) max −36.4 (−33.5) max D1177, D6660
50 vol % in DI water
B,D
Boiling point, °C (°F),
108 (226) min 104 (219) min 108 (226) min
50 vol % in DI water
Undiluted 163 (325) min 152 (305) min 163 (325 min) D1120
Ash content, mass % 5 max 5 max 5 max D1119
pH, 50 vol % in DI water 7.5 to 11.0 7.5 to 11.0 7.5 to 11.0 D1287
E
Chloride, μg/g 25 max 25 max 25 max D3634, D5827
Water, mass % report report report D1123
F F F
Reserve alkalinity, mL report report report D1121
G
Effect on automotive finish no effect no effect no effect D1882
(use clear coat thermoset
urethane or acrylic urethane finish)
A
Type V engine coolant is ethylene glycol base containing glycerin. Other ingredients that do not meet Specifications E1177 and D7640 shall not be substituted in this
blend.
B
For purposes of determining conformance with this specification, an observed value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing
the specification limit, in accordance with the rounding method of Practice E29.
C
Test Methods D1177 and D6660 work with glycol/glycerin mixtures. Field test devices based on refractive index and density are under development.
D
Some precipitate may be observed at the end of the test. This should not be cause for rejection.
E
In case of dispute, Test Method D3634 shall be the preferred test method.
F
Value as agreed upon between the supplier and the customer.
G
Currently, many vehicle manufacturers prepare test panels using the specific paint finishes employed on their actual products. Coolant suppliers and vehicle
manufacturers should agree on the exact test procedures and acceptance criteria on an individual basis.
NOTE 3—Prediluted coolants are intended for direct addition to an engine cooling system with no further dilution. However, if circumstances require
addition and prediluted aqueous engine coolant is not available, use the appropriate engine coolant concentrate (Type I, II, or V) diluted to 50 volume
% with water of at least the quality outlined in Table X1.1.
4.7 When diluting engine coolant concentrates for actual service, use deionized (demineralized) or distilled water, municipal
(treated) water, or a low mineral content well water (see Appendix X1, Table X1.1). This procedure will minimize the formation
of hard water scale and avoid the introduction of mineral components, such as chlorides and sulfates, which can increase the
corrosion rate of aluminum and iron.
4.8 When installed in accordance with the vehicle manufacturer’s recommendations and those on the product label, engine coolant
concentrates or prediluted glycol base engine coolants shall be suitable for use in a properly maintained cooling system (Appendix
X1) in normal light-duty service for a minimum of one year without adversely affecting fluid flow and heat transfer.
5. Detailed Requirements
5.1 Glycol base coolant concentrates and prediluted coolants shall conform to the physical and chemical requirements prescribed
in Table 2 and Table 3 depending on coolant type (see 1.2).
5.2 The requirements listed in Table 2 and Table 3 for prediluted coolants (Types III, IV, and VI) are prescribed for the coolant
as packaged, without further dilution or adjustment.
5.3 All coolant concentrates and prediluted coolants shall conform to the performance requirements listed in Table 4.
5.4 Coolant concentrates shall be diluted for performance testing as described in the individual ASTM test methods.
5.5 If the freezing point of the prediluted product is below –36.4 °C (for Type III a
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