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Tire Service Blog

The Truth About Blown Head Gaskets

The head gasket is located at the top of the engine block under the head. Its purpose is to contain engine compression and to separate the three liquids in the engine from each other. If the gasket is "blown," meaning if it fails in its purpose, the consequences are serious and action must be taken to correct the situation. The cost of a new or slightly used gasket is inexpensive; however, the labor is costly, as accessing the engine and head gasket takes time.

Some vehicle owners may not be aware of the significance of a blown head gasket or because of the costs involved, may choose to ignore the problem. A blown head gasket is serious and can only get worse, so to find a replacement, people shop at auto parts stores like Grand Prix Performance. When searching, consumers should know the function of the head gasket, the types of head gasket failures, the consequences of a blown head gasket, and how to fix the head gasket. 

Overview of the Head Gasket and what Causes Failure

The internal combustion engine is standard in cars, trucks, and motorcycles. The engine utilizes a spark from the spark plug to ignite a fuel/air mixture that explodes in the cylinder. The explosion moves a piston that turns the crankshaft. The crankshaft transfers that energy to the transmission and onwards to the wheels. The head gasket helps keep this explosive system contained. 

The lubrication system is the oil that circulates between the engine parts and allows them to move freely with less friction and heat buildup. The coolant system’s primary function is to reduce heat. The head gasket seals the lubrication fluid, the coolant fluid, and the fuel/air mixture away from each other and prevents them from escaping outside the engine block.

Causes of a Blown Head Gasket

When the head gasket fails, the consequences are serious and they can become worse if the problem is not addressed. Therefore, it is important to know some of the main reasons that head gaskets fail in order to prevent failure. The main problems are discussed in the following chart.


OPERATION :: Ignition timing is incorrect or the cooling system is inadequate 
INSTALLATION :: The factory may have had errors in materials, bolts, and sealers, or the engine construction was faulty 
DESIGN :: New vehicle models may have weak gasket designs or engine difficulties that cause thermal stress 

The main causes of gasket failure are in the design room, the factory, and in the engine’s support systems. While vehicle owners can do little about design or installation flaws, checking the vehicle’s operating systems is advised after purchasing, and throughout the life of vehicle.

Consequences of Head Gasket Failure

If the head gasket fails, the three liquids can cease to perform their individual functions, which will cause the engine to underperform or stop performing. If the engine experiences deficits in performance, the problems flow downstream to engine parts and other vehicle systems. If any of the three liquids is allowed to mix, the engine and other vehicle systems can suffer short and long term deficits, and dangerous conditions may arise.

If the Liquid is Lost

When either fuel, coolant, or oil is lost due to leakage, it can create a messy condition, but is not serious as long as the fluid is topped up. To keep the engine fluids topped up though, the owner would need to be aware of the condition. If the coolant fluid or oil is allowed to stay at a low level, the engine can overheat and warp engine components.

If Fuel Mixes with Coolant or Oil

Serious engine damage can occur if the coolant leaks into the fuel cylinders. The coolant raises compression levels and the coolant superheats. The result is broken or warped pistons, valves, and other components. White smoke from the exhaust is a sign of mixed fuel and coolant. The white smoke is partially steam, which can cause damage to the catalytic converter. The combustion in the fuel chambers, when mixed with engine oil, can cause the oil to burn. Blue smoke from the exhaust indicates a fuel and oil mixture.

If Oil Mixes with Coolant

When the oil and coolant mix together, they contaminate one another. Their purpose in either lubricating and cooling is compromised and can cause fatal destruction to the engine. To know if this condition is present, the vehicle owner should know some of the signs. Coolant with oil contamination presents as an oily film first, then a discolored texture, ending in a brown sludge. Oil with coolant contamination looks like milk chocolate on the oil dipstick, the bottom of the oil pan, the valve cover, the oil cap, or the crankcase breather.

Seriousness of a Blown Head Gasket

A head gasket, like other mechanical systems, usually suffers and fails at its weakest point. The weakest points are the areas between cylinders where the material is thin, the subtle variations in the thickness of the metal, and the insertion points where the bolts affix the head to the block. These weak points are exacerbated in the design stages, during factory or aftermarket installation, or because of the operating conditions in the vehicle. 

The situation is serious as replacing the head gasket is labor-intensive and expensive. It is also serious because other operating conditions may have caused the problem, which may be time-consuming and expensive to repair as well. Additionally, the blown head gasket may have caused further problems in other engine parts or caused irreversible damage to the engine.

Fixing a Blown Head Gasket

If the blown head gasket has caused catastrophic damage, a complete engine may need to be installed or a new vehicle purchased. If the engine is redeemable, the head gasket should be replaced. When replacing, consumers should search by the make, model, and year of the car and obtain the newest generation of head gasket possible along with updated instructions and newer generation tools. Vehicle owners should follow the instructions carefully so as not to damage the gasket during installation or cause damage to the engine in the future. Alternatively, people should engage a professional to do the job. To replace the head gasket, a few major steps are required. 

The first step is to remove the cylinder head from the engine block to expose the head gasket. Both the head and the block should be inspected for damage, flatness, or any problems that may have caused the gasket to fail or may cause future head gasket failure. Both the head and block should be cleaned with solvent and lightly brushed to remove debris. Sanding or polishing the surface can also help remove any residue. Do not overwork the surface; use a bead blaster, or hammer on the head, block, or gasket, as overworking or damages are irreversible.

Head Gasket Installation

Use a gasket dressing or sealer, preferably one recommended by the gasket manufacturer or compatible with the gasket’s material. Some people prefer to let the dressing cure for twenty minutes to an hour before placing on the block. Place the head on the gasket and follow the manufacturer’s instructions for torquing the bolts. Some installers complete most of the torquing, and then wait overnight to finish the final squeeze of the bolts.


A blown head gasket is a serious issue, as mechanical problems in the vehicle may have caused the problem and will need fixing. In addition, the head gasket problems may have caused engine failure or serious damage to the engine components, and that situation will need addressing. It is a devastating problem to experience, because fixing it will cost the vehicle owner time and aggravation if he or she is doing the work, or it will be expensive to have a professional fix it. 

Many vehicle owners are not aware of the signs that indicate that the head gasket is failing or has failed, or it could fail so quickly that nothing can be done to prevent it. Because a blown head gasket is so serious, vehicle owners should do their best to perform regularly scheduled maintenance and prevent operating problems before they occur. 


Written on Wednesday, October 22, 2014 by
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