Coolants
Jim Halderman
1
1
Jim Halderman
Former flat-rate technician
and instructor and a business
owner. Author of many
automotive books and lives in
Dayton, Ohio.
http://jameshalderman.com

2
Topics to be Discussed
Engine coolants- Purpose and function
Water (1/2 of the coolant)
Coolant Types
Cooling system testing
Cooling system service

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What is Coolant?
Coolant is a mixture of:
1. Water (50%)
Additives: About 3%
2. Anti-Freeze
(ethylene glycol-about 93%)
3. Corrosion inhibitors
(additives)
Ethylene
Glycol: 47%
Water:
50%
Coolant
Need to know
4
Additives
The major additives:
1. Reduce corrosion
2. Buffer (control) pH
3. Add color (dye)
Need to know
5
Water
Water is the principal ingredient and:
1.
2.
3.
4.
5.
6.
Is inexpensive
Is a very efficient heat exchange fluid
Has excellent thermal conductivity
Has a good specific heat
Freezes at 32°F (0°C)
Boils at 212°F (100°C)
The water used in coolant must be clean & pure.
Need to know
6
Good Water
The American Society for Testing and Materials (ASTM)
standards for water quality include:
Chloride <40 ppm
Sulfate <100 ppm
Calcium <100 ppm
Magnesium <100 ppm
Total Hardness <170 ppm
pH Range: 5.5—9.0
Iron <1 ppm
Nice to know
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Freeze and Boil
Pure Water
Freezing
Point
0° C (32° F)
50/50 AntiFreeze/Water
-37° C (-35° F)
70/30 AntiFreeze/Water
-55° C (-67° F)
Boiling Point
100° C (212° F) 106° C (223° F)
113° C (235° F)
Need to know
8
Ethylene Glycol (EG)
Ethylene glycol is the base
antifreeze used in every
OEM factory fill.
The additive package will
vary.
Need to know
9
Propylene Glycol (PG)
• Only sold to the
aftermarket
• Not recommended for use
by vehicle manufacturers
• More expensive than EG,
Increased cost is $/gallon
• Still toxic but is not as
sweet as EG
Need to know
10
Embittered Coolant
Embittered = tastes
awful
Embittering agent is
required (denatonium
benzoate, 30 ppm)
Required in California
and Oregon since
2004 but not included
on the label.
Need to know
11
Bittered States
At this time, 7/20/10, 12 states require antifreeze with
a bittering agent: dentonium benzoate. They are:
• Arizona
• New Mexico • Virginia
• California
• Oregon
• Vermont
• Maine
• Tennessee
• Washington
• New Jersey • Utah
• Wisconsin
4 states: Illinois, Massachusetts, New Hampshire,
and Ohio are working on a similar rule.
IAT (Usually Green in Color)
Inorganic Additive Technology
(IAT) antifreeze can contain:
•
Silicates (possible
abrasive dropouts)
•
Phosphates
•
Borates
IAT is considered obsolete and can cause early failure of
ceramic-phenolic seals used in newer water pumps.
Need to know
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IAT
Inorganic Additive Technology (IAT) is the traditional
green coolant used in most older vehicles. This
solution offers fast-acting corrosion protection, but
the additives are quickly consumed, exposing the
cooling system to possible corrosion problems if not
changed regularly.
Need to know
14
OAT (Usually Orange)
Organic Acid Technology (OAT) is the
formula found in DEX-COOL®, and is
usually the antifreeze/coolant of choice
for GM, VW, and many Japanese/Asian
vehicles. This formula is engineered to
offer long-life corrosion protection.
The downside of OAT is it is not compatible with other types of
coolant (IAT and HOAT). In fact, Ford, Chrysler and others say to
not use this type of coolant in their newer models.
Need to know
15
OAT-continued
NAPS=nitrates, amines,
phosphate and silicate free
Nice to know
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OAT=DEX-COOL is one brand
Nice to know
17
DEX-COOL’s Unique Formulation
• DEX-COOL uses Ethylhexanoic Acid (2EH) as a corrosive inhibitor
• 2-EH is prone to damage plastics like
Nylon 6.6 used in intake manifold
gaskets and radiators
• G30 OAT and Peak Global OAT do
NOT use 2-EH
Nice to know
18
GM DEX-COOL Problems
Class action suit; GM may have to pay for
intake gaskets on V-6s (V-8s still being
determined)

Brown Gunk on radiator cap
Need to know
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Rust in Engine
• DEX-COOL + Air= rust
or
DEX-COOL + core sand
= Brown gunk
Need to know
20
DEX-COOL Concerns
• Root cause= air entering system
• Check cap replace cap
• Air causes ‘Brown Gunk’
• Rust then causes blockages
Need to know
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Dex-Cool &
OAT that meets GM Spec.
Prestone markets an OAT antifreeze (Extended
Life)
“compatible with ANY antifreeze/ coolant” that
meets the GM Dex-Cool spec.
It is less expensive than Dex-Cool-labeled
products because of no-royalty cost.
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HOAT (Many colors)
Hybrid Organic Acid Technology (HOAT) is found in newer
Ford, Chrysler and Mercedes vehicles. Said to use the very
best aspects of both IAT and OAT, HOAT is a very protective,
long-life coolant.
Need to know
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HOAT=Red; Pink; Yellow or Blue
Nice to know
24
POAT Coolant
• Phosphated Organic
Acid Technology
(POAT)
• Dark Green in color
• Used in Mazda-based
Fords (2008+)
• same as Mazda FL22
• $34.95 per gallon
Ford Motor Company & E-OAT
The E = European, low silicate and phosphate free
•Ford of Europe has validated Dex-Cool and uses it with no problems.
•Ford of U.S. has reengineered all of their new engines (No- Cavitation water
pumps and no-silicone rubber or Nylon 66) to work with this formula.
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Ford/Mercury Coolant
Pre 1999
99—01
2002
2003
2004
The 1999—2001
Cougar used a OAT
Dex-Cool clone, but had
issues with water pump
cavitation.
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Coolant Summary
•
Ethylene glycol - Most ethylene glycol coolant is any color and contains about 93% ethylene glycol
plus water and additives.
•
Propylene glycol - less harmful to pets and animals because it is not sweet tasting, although it is still
harmful if swallowed.
•
Organic acid technology (OAT) antifreeze coolant – This type is ethylene glycol based but it does
not contain silicates or phosphates. It is usually orange. DEXCOOL is an OAT coolant.
•
•
Hybrid organic acid technology (HOAT) – This orange, green, red, blue or yellow coolant is an
ethylene glycol based coolant similar to the OAT- type antifreeze as it uses additives (a low amount of
silicate)
•
VW/Audi pink - Most of these coolants are HOAT (ethylene glycol-based with some silicate and
contain an organic acid) and are phosphate free.
•
Asian red – This coolant is ethylene glycol-based and is silicate-free, yet contains phosphate.
•
Mercedes and Ford yellow – This conventional ethylene glycol coolant has low amounts of silicate
and no phosphates.
•
•
Mercedes Lifetime – Very expensive, can be drained, filtered and reused.
Korean or European blue – This conventional ethylene glycol coolant has low amounts of silicate and
no phosphates.
Nice to know
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Replacement Antifreeze
The best choice is to follow the vehicle
manufacturer’s recommendations
OR
you can follow the recommendations of reliable
antifreeze manufacturers
Need to know
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Passivation
• Passivation= is a chemical reaction the takes
•
•
•
•
place between coolant additives and the metal that it
protects
Takes a few days or few weeks
It creates barrier between the metal and corrosion
Each chemical package does its own passivation
if you change chemical packages, passivation has to
start over
• It boils down to: DO NOT CHANGE PACKAGES.
Nice to know
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“G” Designations
• G= Glysantin –trade name of BASF. Valvoline
(Zerex) in the US.
• G30, G33, G34= non-silicate and phosphate
free (DEX-COOL replacement)
• G05 = Phosphate free-low silicates (Asian
formula and Chrysler HOAT)
Nice to know
31
“G” Designations-continued
•
•
•
•
?
G11=Blue VW used before 1997
G12=Pink/Red VW 1997+
G12=Purple VW 2003+
HOAT formulation; phosphate free
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“G” Designations-continued
•
•
•
•
?
G48=Low Silicate and Phosphate free
Blue Color
NAP =nitrates, amines, phosphate free
BMW
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Universal Coolant
• Arctic Blend
• Recycool
•Prestone Prime
Coolants that have been formulated to be used in
any vehicle
Nice to know
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Color
The color helps us
identify a coolant
leak. It also helps us
identify the additive
package.
Should not be used
as an indicator what
to use-some Chrysler
vehicles used HOAT
coolant that was
green
Need to know
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Substance pH
Hydrochloric acid
pH
Acid
pH is a measure of acidity or
alkalinity of a solution.
Less than 7 is considered acidic.
Greater than 7 is considered
alkaline.
Alkaline
Nice to know
-1.0
Battery acid
0.5
Lemon juice
2.4
Cola
2.5
Vinegar
2.9
Orange or Apple juice
3.5
Acid Rain
<5.0
Tea or healthy skin
5.5
Milk
6.5
Pure water
7.0
Healthy human saliva 6.5 – 7.4
Blood
7.34 – 7.45
Sea water
7.7 – 8.3
Hand soap
9.0 – 10.0
Household ammonia
11.5
Bleach
12.5
Household lye
13.5
Caustic Soda
13.9
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pH Effects
Fresh antifreeze pH= 9 and 11
Used coolant pH= 7.5 and 10
It can also increase electrolysis
( the dissimilar metals in contact with an electrolyte can
produce a simple battery)
Need to know
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pH of various coolants
• IAT= 9.0-10.5 new
• OAT= 7.5-8.5 new (G30 and G34
designation)
• HOAT= 7.5-8.5 new (G05,G48,G11 or
G12 designation)
Need to know
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pH Tests
pH can be measure using test strips or a
meter.
Fairly accurate and costs pennies/test.
Need to know
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pH Meter
This Milwaukee is probably more accurate and cost $30.00.
Need to know
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Corrosion
Corrosion is the “decomposition of metal”
(called rust or aluminum oxide, the whitish
material that forms on aluminum components)
Oxide formation:
1. eats away at the parent material from the
outside
2. forms an insulating barrier for heat transfer
Need to know
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Metal Corrosion
This iron tube has
been ruined by rust.
Need to know
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Corrosion
aluminum oxide, often
found on coolant
outlet/stat cover
Need to know
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Corroded Water Pump
One of the reasons for the removal of silicates from coolant
Need to know
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Corroded pump can cause:
• reduced coolant flow
and an overheating
condition
Need to know
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Cavitation
Cavitation
Cavitation is the sudden formation and collapse of lowpressure bubbles. With gasoline engines, the pressure drop
can occur at the inlet of the water pump. These bubbles
produce a pitting of the solid metal .
Need to know
47
Cavitation Damage
The very low pressure can produce gas bubbles that
implode next to a metal surface. The implosion blasts
particles from the surface.
Need to know
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Diesel Wet Sleeve Cavitation
The sleeve can vibrate
during the combustion
stroke producing the
pressure drop, bubbles,
and metal erosion. Heavy
duty coolants contain
supplemental coolant
additives (SCA) to help
prevent this.
Need to know
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Galvanic action
• Galvanic activity does not require an
outside source of voltage
• The higher the conductivity of the
coolant, the greater the amount of
corrosion
Need to know
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Metals
Nice to know
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Bi-Metal Corrosion
Ions move from more active metals to less active metal
through the coolant which acts like the electrolyte
Nice to know
52
Electrolysis
Electrolysis requires the use of an outside voltage
source.
•When electrical ions move from metal to the
coolant, they can take metal atoms with them
• This metal transfer can eat holes in a heater core
or radiator.
•Electrolysis holes will usually start from the inside
and have a dark coloration.
Need to know
53
Testing Coolant with a Voltmeter
• This test gives variable and questionable
results depending on many factors
• Galvanic=less than 200 mV
• Electrolysis= (engine running and
accessories switched on and off)=less than
300 mV. This check can locate faulty
ground connections
Need to know
54
Radiator Voltage
Connect the negative
voltmeter lead to a
good ground (this
radiator has a plastic
filler neck), and
immerse the positive
lead into the coolant. A
reading of 0.300 V or
greater indicates
corrosion is probably
occurring.
Need to know
55
Coolant Condition
This “green” antifreeze has a
clean, bright appearance. The
other types will have a different
color but should also appear clean
and bright.
A muddy brown or rust-reddish
color indicates that corrosion is
occurring.
Need to know
56
Freeze
Protection, Refractometer
A few drops of coolant are placed
under the sample window. The
technician then holds the unit up
to light and looks through the eye
piece (right end).
Eye Piece
Sample
Window
Need to know
57
Refractometer Image
Shadow
Read Here
The image will show the amount
of freeze protection and is read at
the scale at the bottom edge of
the shadow. This unit can check
EG and PG antifreeze freeze
protection and battery specific
gravity.
Need to know
58
Freeze Protection, Test Strips
Test strips will change color when
they are dipped into the coolant, and
the color change is compared to the
container.
Test strips are fairly accurate, easy to
use, and inexpensive.
Need to know
59
Coolant Corrosion Protection
The new test strip color is compared to the color pads on
the container to determine the amount of freeze protection
and corrosion protection.
Need to know
60
Coolant Replacement
1. 15 to 20% remains in the system after it has
been drained
2. Fill system with antifreeze first and top off with
water
3. Be sure to use the specified coolant
(GM warns not to reuse coolant drained from the system)
(Mercedes has a lifetime coolant, drain, filter, & reuse)
Need to know
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Coolant Replacement-#2
• Check the pressure cap and radiator for faults
• Check all hoses and always use coolant hose
Need to know
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Coolant Recovery and Storage
Some shops recycle used
antifreeze
Should be stored until
picked up for recycling
Notice double containers
to help avoid spills
Need to know
63
Flushing a Dirty System
1. Drain system
2. Fill system with clean water & chemical
3. Run system to operating temp. (Heater on)
4. Drain system & fill with clean water
5. Repeat until drain water runs clear
Any remaining flush agent will upset pH.
6. Fill system with 50/50 antifreeze/water mix
7. Run system to operating temp. (Heater on)
8. Adjust coolant level
Caution: If flushing a really dirty system,
be prepared to repair some leaks.
Need to know
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Flushing
Some communities permit draining into sewer.
EG and PG will biodegrade. There is a problem
however if coolant is spilled on open ground.
Need to know
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Be sure to clean the
overflow/surge tank
It should empty if you
start draining with the
cap in place.
Need to know
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Mix Coolant 50/50 or use premix
?
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Coolant Exchange Machine
Most shops use machines
like this.
Coolant drains have
become fragile and hard
to find.
Need to know
68
TECH TIP
• Check the freezing Point after service
• Should be -34 degrees F (proper 50/50
mix)
• If higher (i.e. -20 F) this means that there
is too much water.
• If lower (i.e. -40 F) this means that there is
too much antifreeze
Always check or
replace the radiator pressure cap
The cap can be located on
1. the radiator
2. The coolant recovery reservoir
3. The upper radiator hose
Note the pressure.
Need to know
70
Cap has two seals
Upper Seal
Filler Neck
Lower Seal
To CRR
What will happen if the upper seal fails?
What will happen if the lower seal fails?
Need to know
71
Never open when hot!
1 psi will increase the coolant boiling point 2.7oF.
A 15 lb. Cap will increase the BP 40.5oF.
What can happen if the cap is removed from a hot system?
Need to know
72
Proper Fill
All of the air must be removed from the
cooling system by one of these methods:
• Bleeder screw: lets air escape
• Air Lift: evacuates system before fill
• Spill-Free Funnel: Lisle #22150
• Fluid Exchange: requires special
equipment
Need to know
73
Bleeder Valves
• Use a clear hose attached
to the bleeder valve and
the other end in a
“suitable” container
• Prevents coolant from
getting on the engine and
gives the technician a
visual clue as to color of
coolant
Need to know
74
Leak Detection
A good system holds pressure
Tracer dye and some antifreezes glow under UV light
Need to know
75
What should Technician's do?
• Check service information for the designated coolant
and replacement interval
• Check the coolant appearance and level at every
service
• Check the pressure cap appearance at every service
• Check the appearance and pH for signs that the
coolant should be replaced before the regular service
interval
• Check Freeze Point, pH, and Galvanic/Electrolysis
Need to know
76
Typical Questions/Answers
1. Are all green antifreezes the same?
A. No-Chrysler used HOAT coolant that was green
like IAT coolant
2. Can DEX-COOL be replaced with conventional
green coolant?
A. Yes, but then the coolant has be replaced
every 24 months or 24,000 miles
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Questions/Answers
3. Can coolants be mixed?
A. No
4. Is DEX-COOL propylene glycol ?
A. No. DEX-COOL and all other coolants are
ethylene glycol except one labeled
propylene glycol and is never used from
the factory
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Summary
• Not all coolants are the same
• Not all tap water is OK to use
• Premixed coolant usually produces good
results
• Check the coolant freezing/boiling point
• Check the coolant pH
• Always check or replace the pressure cap,
especially on DEX-COOL vehicles
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Contact Information
• www.prenhall.com/automotive
• http://jameshalderman.com
Jim Haldermanjim@jameshalderman.com
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