I was curious on how to check/replace an exhaust valve? My r53 (aka Joan) is throwing a p0304 code or misfire on cylinder 4 and was curious if it was the exhaust valves. I am handy with tools so if anyone knows of a DIY let me know.

Thanks

 

A cylinder leak down test will usually help determine this. The great feature of the C.L.T. is the fact that you can hear where the air is leaking out of the cylinder. When a cylinder has high percentage of leakage, first check the oil filler cap. Do you hear a hissing sound? If so, you may have pressure leaking by the rings. Is there air escaping out the exhaust? Is it escaping out the intake system? Then a burned valve may be the problem. If two adjoining cylinders have similar low readings and you hear leakage out the other cylinder, then a failed head gasket may be the problem.

 

It doesn't seem to misfire all the time though. I feel i would hear this hissing sound all the time correct? And when it does misfire i do hear a spudder like sound? I do not know how to check the pressure on the cylinders? Is this something i can do or does the car need a mechanic?

 

Check plugs,wires, and coil. Move the wires around and see if it follows the wire. That will eliminate then. Change the plugs and remember to torque them down to 22ftlbs on a cold engine. That will eliminate them. You need a special tool to do a leak down test.

 

The plugs are brand new torqued to spec. I have already checked the coil it is fine and the wires appear to be alright as well. Which leads me to believe its A) the exhaust valve B) vacuum leak C) low pressure in the cylinder. I just have no idea how to test for these myself and i hate paying someone to do the work i know i can do

 

As seen in the video you need a special tool like this to do it. If you don't have the tool you will need to pay someone or borrow one. R53's are known to burn up valve guides. Sorry