[NoNeck]

The symptoms you’re likely to notice the most with a burnt exhaust valve is a loss of power from the engine and an increase of fuel consumption as the engine is run harder to do the work expected of it. Other symptoms will be dependent upon how badly burned the valve is.

When the edges of an exhaust valve burn, the combustion chamber no longer seals and not only do you lose compression in that cylinder, unburnt hydrocarbons will be exiting before they can be ignited.

Running an engine low on oil will often burn one or more valves before the main bearings start to pound. Otherwise, a lean fuel mixture can cause this, too.

On vehicles with a full exhaust system, the sound can be hard to detect. A cylinder leakage test will pinpoint it fairly well. Your pressure loss will be fairly high and you’ll hear the pressurized air escaping through the exhaust system, rather than through the intake or the crankcase. If you hook up a vacuum gauge, you may notice a steady loss of vacuum at idle if a valve is burnt or sticking.

You’ll be looking at a valve job to correct it, or else swap out the cylinder head altogether.

POP