A head gasket failure can cause a severe disruption in the normal function of your car’s engine. The gasket is located between the engine block and cylinder head. It is also responsible for maintaining compression. When the gasket fails, coolant and oil can leak inside the cylinders while the level of compression declines.
You may be able to continue driving for a short time following a head gasket failure. However, you will likely experience problems. Your engine may begin to ride roughly due to the compression loss; exhaust gases may access the cooling system; and because the leaking coolant in the cylinders causes more exhaust, your catalytic converter may fail. With time, your engine will suffer damage.
This article will present the most common reasons for a head gasket failure. In the event that the component has failed due to another issue, it is important to find and fix the initiating problem.
Head Gasket Failure Due To An Overheating Engine
Gaskets often fail due to overheating because of their placement just between the cylinder head and engine block. When the temperature in the engine increases, the block and head expand (called thermal expansion). The problem is, both parts are designed with different metals. Their rates of expansion vary and as a result the gasket, squeezed between the block and head, endures a high level of structural stress. With time, it fails.
An engine can overheat for a variety of reasons. For example, it can happen due to a failing thermostat, bad water pump, clogged radiator, or heavy load for which the cooling system is incapable of managing. The important thing is to identify the root cause of the overheating, and fix it before installing a replacement head gasket. Otherwise, the replacement may also fail when the problem recurs.
Was The Head Gasket Installed Incorrectly?
Head gaskets sometimes fail due to one or more errors made during their installation. For example, the installer may have failed to fasten the head bolts in the proper order (there is a specific sequence recommended by the manufacturer). Or, the wrong torque may have been used when installing them.
Another common problem is the surfaces of the block and head are not completely clean at the time the gasket is installed. Small debris can compromise the seal, leading to coolant and oil leaks. These leaks can lead to overheating, which will eventually cause the gasket to blow.
The block and head must be smooth in order for the head gasket to provide a tight, leak-free seal. If either are not smooth at the time of the installation, leaks will be nearly inevitable.
As with an overheating engine, it is important to determine the underlying reason for the component’s failure so it can be addressed. For instance, if the cylinder head is not smooth, the mechanic should restore its smoothness prior to installing the replacement gasket.
How A Replacement Is installed:
To begin, a blown head gasket installation should be performed by a trained mechanic or someone with extensive experience working on cars. Although the component is relatively small, installing it correctly can be problematic without the proper tools and experience.
The first step is to remove the cylinder head. Once it has been removed from the engine block, check the smoothness of both surfaces. If either are outside the proper specifications, have them restored.
Second, assuming the head and block are smooth and flat, clean both surfaces of debris. Then, place the new gasket in position. When installing and tightening the bolts, it is critical to do so in the proper order. It is also important to use the right amount of torque.
Third, with the gasket in place and the bolts fastened, replace the cylinder head. If you found it necessary to remove any other parts in order to reach the gasket (e.g. exhaust manifold), replace them as well.
The head gasket, though rarely seen, plays a significant role in maintaining your engine’s performance. If it fails, make sure the underlying cause is diagnosed and resolved before a replacement is installed.