I just wrote a little article about blown head gaskets. Now I’m going to tell you how the repair usually goes. While there are a number of ways a cylinder head can be damaged, I’m going to focus on the most common way: being warped due to overheating.
So the poor, sick vehicle is in the shop, we’ve done the appropriate tests and determined it has a failed (blown) head gasket. Well, why did it fail? The proximate cause is almost always overheating but why did it overheat? Leaky water pump? Blown coolant hose or radiator? What is the condition of the coolant? Once the root cause of the problem has been located then we can get on with the primary repair, the cylinder head.
The next thing we have to do is remove the cylinder head for repair. If the engine is a V6 or V8 we’re going to strenuously recommend removing both heads and re-sealing them both. Once removed the heads are pressure tested for cracks and to insure the valves are sealing properly. If there are any cracks the head will be replaced. If not, the head will be surfaced, that is machined to be sure the side that sits against the head gasket is flat and smooth enough to seal properly. If the valves aren’t sealing as they should, they and their seats are ground so they will. The valve seals are replaced and the valve springs tested for proper tension. While the heads are being machined we’ll clean the block deck and check it for flatness or other damage.
OK then, the machine work is done and it’s time to reinstall the heads. We use only the highest quality gaskets when we reassemble an engine. Whenever they’re available we use multi-layer steel (MLS) head gaskets. If we’re working on a timing belt engine we’re going to replace the timing belt, the timing belt tensioner and idlers and, most likely, the water pump. We’re going to recommend new coolant hoses and new belts too in order to limit future problems. The old coolant is flushed out, fresh coolant installed and the engine oil is changed.
Road Trip! Well, road test really. Out we go to insure that everything is working as it should. When the car gets back to the shop, one final inspection and it’s ready to go home, just as good or better than before there was ever a problem.
From your Local Mechanic, All Tune and Lube Total Car Care. Complete Auto Repair and Maintenance.