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A head gasket is an important car gasket, located between the head and the block of the engine. It keeps the head separate from the block, cushioning the two, and preventing them from touching and creating friction. A blown head gasket can occur when a vehicle overheats. The process of repairing a blown head gasket is a lengthy but relatively simple procedure.
Before embarking upon the procedure, the battery of the car should be disconnected. Not doing so could cause a spark, resulting in a possible electric shock to the mechanic. Remove the timing chain casing, and mark the timing position of the gears. To do this, use a paint marker, and mark a small spot where each timing notch is located. This ensures their correct alignment during reassembly, and prevents the mechanic from having to retime the engine following the correction of the blown head gasket.
Remove the timing chain, followed by the tappet cover. The next step will depend on the engine type. With a six-cylinder or an eight-cylinder engine, a removal of the intake manifold is needed, followed by the removal of the head bolts. In a four-cylinder engine, which is a single head engine, this step can be skipped. Completely lift the head off the engine block, and remove and discard the blown head gasket.
Check to see if the block itself is level. Use a straight-edged ruler to see if any gaps are present between ruler and the engine block. If any are present, the block is warped and needs to be leveled out. Repeat the process with the head. If no gaps are present between the ruler and the head, it is safe to reassemble the engine using a new head gasket.
Put the gasket upon the engine block. Place the head back on the engine. In a crisscross pattern, working from the center out, use a torque wrench to tighten the head bolts to the proper torque level required by the vehicle. A user manual will be required to determine the proper amount of torque for this step.
Proceed with reinstalling the intake manifold. Replace the tappet cover, timing chain, and timing chain casing. Drain and change the vehicle's oil. This will need to be done to eliminate any moisture in the oil caused by a possible antifreeze leak, which can result in the occurrence of a blown head gasket.
Change the antifreeze as well. This will allow it to cool better, preventing the engine from overheating once again. Hook the battery up, and the procedure is complete.
I keep reminding my adult children to keep an eye on the engine's oil and coolant levels. Head gaskets generally need a little "help" from the driver to get damaged. Driving a car to the point of overheating and not checking on the fluids or adding oil when necessary will do it.
When I started buying my own cars to drive, I remember a mechanic saying never buy a used car with a blown head gasket. He said the repair itself wasn't hard, but the labor costs could be significant. I thought he was exaggerating, until I drove one car to work and the engine overheated. Smoke started pouring out of the hood. I had it towed to a garage and the mechanic handed me a repair estimate of over $500. He said the head gasket was blown and the heat warped the engine block. The entire car wasn't worth $500, so I sold it for scrap.
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