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Blowing a cylinder head gasket is a common mechanical emergency, but it’s not worth losing your own head over. Blown head gaskets are easy to prevent with regular check-ups. It’s all about keeping cool under pressure. And, that’s sound advice for both the car and its driver.

What does a cylinder head gasket do?

The cylinder head gasket seals the combustion chamber of your engine block to prevent hot exhaust gases from escaping and oil or coolant from entering. But, because combustion gasses run so much hotter than oil or coolant, the temperature fluxes can cause that seal to degrade over time. This can occur faster if the coolant level is low and conditions are compromised, which can limit the cooling system’s effectiveness.

When was your last coolant check-up?

Coolant is the true lifeblood of your engine. It helps the engine maintain proper temperature to avoid overheating. Low coolant levels or neglected/contaminated coolant are common causes of a blown cylinder head gasket. Many drivers never think to do engine coolant check-ups. Many drivers only think to do engine coolant check-ups twice per year—before winter and summer. Your coolant should be checked each time you open the hood, not just seasonally. Coolant levels have little do with outside temperature, and everything to do with your engine’s internal temperatures.

First: Check your coolant levels.

Vehicle manufacturers have made it very easy to check your coolant level in your vehicle. Just open the hood and make a visual observation of your expansion coolant reservoir.. If the coolant is at the “full” line, you’re good to go. If not, make sure to top it off with a compatible coolant like PEAK Long Life ®50/50. Now, if the coolant level is low in your radiator tank but full in your overflow tank, that might signify an even more troubling diagnosis. In that case, we recommend a professional check-up of your vehicle.

Second: Test the condition of your coolant.

Engine systems are designed for a 50/50 mixture of water and inhibited glycol. If that mixture is off, it will raise the temperature, your engine will overheat, and your coolant will start boiling off. When the coolant level gets too low, air pockets form in the cooling system. This can reduce its own effectiveness to cool and properly control operating temperatures of your vehicle. If that happens, the cylinder head gasket can be compromised and then, well, you know what happens next.

In order to test the mixture ratio of your coolant, you will need a handheld antifreeze tester. This is a simple tool that uses a rubber suction bulb to draw a small amount of coolant into a test chamber containing a floating gauge. The best time to check your coolant condition safely is when the engine is cold. DO NOT OPEN PRESSURE CAP WHEN ENGINE IS HOT! If in doubt, check the upper radiator hose. If it is too hot to touch or if it is under pressure (hard to squeeze) do not open the radiator cap. Once you have determined that the cooling system is not under pressure, it is safe to remove pressure cap and test the coolant in your expansion coolant reservoir. Read the directions on your tester for specific testing instructions. The tester will help you to make visual observation on your coolant condition. Once you know the makeup of your coolant, you can adjust as necessary. We recommend using distilled water to dilute the amount of coolant in the system. When raising the ratio of coolant in the system, use a full-strength coolant like PEAK Long Life® Full Strength.

Third: Flush and Refill as needed.

If your coolant is in bad condition (no color, presence of the rust, oil, strong odor, and/or particles), we recommend doing a full flush. Flushing the cooling system removes any junk that may be impeding the flow of coolant through the system. It also refreshes the additives which help prevent corrosion and protect important cooling system components like the water pump, radiator, heater core, thermostat and other parts of your engine. When refilling the system refer to your vehicle owner’s manual for the correct coolant mixture ratio to suit your vehicle manufacturers recommendations. You can use a pre-mixed coolant like PEAK Long Life® 50/50, or customize your coolant by mixing PEAK Long Life Full Strength with distilled water. Make sure to properly capture and dispose of any used coolant in accordance with your local, state and federal regulations.

Flushing a cooling system can be messy, so you may want to defer to your trusted local repair shop. They will also be able to properly dispose of your used coolant correctly, saving you the hassle.

Keep cool and ride on.

A little TLC can go a long way toward helping your car be free from mechanical emergencies.

Check out all the chemical & lubricant products available on NAPA Online or trust one of our 16,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on avoiding a blown head gasket, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

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