You can tell when a manifold tuning valve is bad when oil is leaking through it. You also can tell by inserting the dipstick into the valve and seeing if oil comes out through the dipstick.
Valve cover gaskets leaking oil onto exhaust manifold/s. Bad valve seals. (if oil level drops) Bad PCV valve. Allowing oil into intake manifold/throttle body area.
If you are talking about the EXHAUST manifold then most of the time it's the valve cover gasket that is leaking oil. REPLACE VALVE COVER GASKETS. If you are talking about the intake manifold then it has 2 rubber gaskets in the front and rear of it that leak oil real bad. If oil is on the left are right top sides of the intake manifold were the valve covers are then it will be the valve cover gaskets that are leaking oil.
Check the compression of the cylinders you will have a low reading in the one with a bad valve
its not in the manifold it should be on your fuel rail
Normal cause is the intake manifold itself.Normal cause is the intake manifold itself.
how do you know when valve lifters for 94 mercury villager 3.0 engine r bad
Exhause leak? Bad Muffler? Leaking or cracked exhaust manifold? Bad EGR valve?
If there is oil coming from the exhaust manifold it generally indicates a bad valve stem seal or a worn out engine. (too much crankcase pressure)
A PVC valve is typically bad in a car if a car has an oil leak. Other signs of a bad valve include a collapsed hose and a sludge-like buildup.
hopw do I find the egr valve on a vauxhall signum
If really on top then probably the intake manifold gasket ,study it closely .
1990 Honda accord ex how would you know if idle air control valve is bad?