Cylinder heads are located on top of the cylinders that are inside an internal combustion engine. The pistons close the heads on top of the cylinders, creating a combustion chamber that compresses the contents of the cylinder. Cylinder heads obviously provide an important role in the combustion process, but what many people don’t realize is they have a very lightweight design and construction to them. This causes them to start cracking after about five years of use, especially if they are aluminum overhead cam heads. But if you have cast iron heads then cracks will form eventually.
The common causes
A big reason why cracks form on the cylinder heads is because the valve seats become hardened from the concentrated heating process. This ends up putting more stress on the cylinder heads, causing them to crack after awhile. The engine doesn’t always have to be overheated for this to happen either. All it takes is for the valve seats to be put under stressful conditions for the cracks to start forming on the heads.
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Average Repair Cost
The cost to repair a cracked cylinder varies between different model cars. The average minimum cost you can expect to pay is $500, but with parts and labor costs it could go up to about $1,000. If your car is still under warranty then you should be able to get these costs covered by your dealer. Sometimes new cars will be sold with engines that have a mixture of metals inside of them. For example, a car might have a solid cast iron engine block that will make it appear to be strong. But what you won’t know right away is the cylinder head is made of aluminum and not iron. This increases the chances of weak spots forming in the metal and the engine’s components being incorrectly installed. Once this happens, the cylinder heads will start to crack right away even if the car is new. So always make sure you get a warranty on these areas to ensure you don’t have to pay an extra $1,000.
The best way to preserve the life of your cylinder heads is to keep your radiator filled and make sure you have no stretches hoses or leaky belts. If your car ever overheats then have your head gaskets replaced and the heads checked or cracks. Your auto technician will be able to make the best recommendation at that point as to whether you need to replace the cylinder heads or not.