2003 Mercury Sable Q&A
2003 Mercury Sable Question: BURNT VALVE
A "burnt valve" is a valve which has been heat damaged and is not sealing correctly causing a misfire in the affected cylinder. It is much more common for an exhaust valve to burn than an intake valve because cooler incoming gas help cool the intake valve. A lean running engine or out of adjustment valve clearance can cause a valve to "burn" prematurely. There are various other issues which can cause a valve to not seat correctly resulting in a misfire. A cylinder leakage test is the best way to confirm compression loss due to leaking valves. The repair can be quite expensive. You can begin with the RepairPal estimate - http://repairpal.com/estimator - for head gasket replacement and add to that a few hundred dollars for machine work and any necessary parts to repair the cylinder heads. - Oakman
I recently tried to recharge my ac with the recharge bottles sold at Auto Zone and it did not get cold. So I added more. Thinking I may have over charged the system, I released all the pressure fro...