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What is the primary function of coolant?

Transfer heat from the engine to the radiator for dissipation!

• Combustion temperatures are greater >5400 deg F

• Cooling system removes the bulk of heat

• Coolant circulates 100 to over 300 GPM.

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Antifreeze vs. Coolant

“Anti-freeze” contains a glycol base that lowers the freeze point of the

liquid.

“Coolant” is a general term that applies to any liquid that removes heat and

provides corrosion inhibition. Coolant may be a treated “water only” fluid.

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General Requirements of Coolant

Good heat conductor.

Low freeze point.

High boiling point.

Non-corrosive to metals.

Non-foaming.

Compatible with other commercial coolants.

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What is a coolant made of?

A typical “Premix” coolant is made of:

1. Water

2. Glycol

3. Inhibitor package

4. De-foamer

5. Dye (colorant)

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Engine Coolant Performance

Engine coolant performance is due to the inhibitor package

• Corrosion protection is required for –

• Iron, steel, aluminum, copper, brass, bronze, and lead-based solder.

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Nearly 40% of all engine failures are related to the cooling system

Worn RingsWorn Rings

Scuffed PistonsScuffed Pistons

High Oil High Oil ConsumptionConsumption

Burnt ValvesBurnt Valves

Why is coolant so important?

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Coolant Types

Three general coolant types are used in both LD Automotive and HD Diesel

Applications

1. Conventional

2. Hybrid

3. OAT (Organic Acid Technology)

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Automotive LD vs. Diesel HD

The most important difference between light-duty and heavy-duty coolants has to do with liner pitting protection.

Diesel engines are prone to a specific type of erosion corrosion inherent in diesel engine design.

What is liner pitting?

LINER PITTING or cavitation corrosion caused by imploding vapor bubbles will pit through the liner wall.

Shock wave impact measured at 15 to

20,000 PSI

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What does liner pitting really look like?

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How is liner pitting prevented?

Well-Formulated HD Coolants!

Nitrite and Nitrite/Molybdate combinations work

effectively to prevent liner pitting.

Organic Acids in high concentration

also work effectively to prevent liner

pitting.

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Light-Duty Maintenance

•Maintain proper coolant level

•Maintain glycol content between 30% - 60%

•Drain and replace coolant according to manufacturers recommendations. Generally, 2-3 years for conventional coolants or 40,000 – 60,000 miles. OAT and Hybrid coolants are replaced after 5-7 years in passenger cars.

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Heavy-Duty Maintenance

•Maintain proper coolant level.

•Maintain glycol content between 30% - 60%.

•Nitrited Coolants - Test coolant and replenish depleted inhibitors at prescribed intervals using a liquid SCA or “spin-on filter” containing SCA.

•Drain and replace coolant. According to manufacturers recommendations.

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SCA (Supplemental Coolant Additives)

•Maintain performance of Fully-Formulated HD “in service” coolants by replenishing the depleted inhibitors.

•Use SCA’s to maintain “Conventional” and “Hybrid” coolants.

Why is SCA needed?

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SCA – What happens to coolants over time?

•Additives deplete.

•Depletion of additives (inhibitors) occurs at different rates.

•Glycol degrades.

•Contamination occurs.

•Oil

•Hardness

•Corrosion products

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SCA’s

SCA’s are convenient to use in liquid and “spin on” coolant filters.

SCA’s Control

Corrosion

Rust

Scaling

Oil fouling

Liner Pitting