Low compression on cylinder three

Good morning.

Yes, the cylinder head will have to be removed and the valves inspected for failure. The valves may be burned, head could be warped or piston rings worn out. The failure can be determined once the head is removed.

Roy

You are welcome.

Roy

Rebuilding a cylinder head is a standard procedure but it is normally done at an engine machine shop, then the mechanic reinstalls it on the engine. There is another, more time-consuming test that could have been done. A compression test just tells you the compression is low. A cylinder leakage test will tell you why it is low. Burned intake and exhaust valves are the most common causes, but there can also be leaking piston rings and a leaking cylinder head gasket.

If the mechanic did a cylinder leakage test and found the head gasket to be leaking, as long as the head has to removed anyway for the repair, a mechanic who has your best interest a heart will want to have the head gone through at the engine specialty shop to take care of any worn valves or guides rather than wait for other problems to develop in the near future. The machinist will also check the head for flatness. That can be corrected if it not too bad, to insure the new head gasket will seal properly.