Hello,

I have a 300E with 110,000 miles on it. I get grey smoke from the exhaust between idle and 2500 RPM. I read that this could be valve seals. I did a compression test and each cylinder did the exact same thing. I did three strokes of the engine and the readings (in Bar) were: 9-10-13 on all cylinders. I understand that 8.5 is minimum for these engines. According to Haynes if a reading starts low and then jumps the rings are suspect. But would there be such a coincidence that all six pistons have worn rings? So far, does it look like the valve seals could be problematic? And finally, approximately how much is a stem seal job?

Thanks, Andrei

__________________
With Regards

Have you tried adding a bit of oil to each cylinder and repeating the compression test? If the readings are drastically different (better), that should indicate the rings need renewal.

So that's what's meant by "wet" compression test then? I'll do that ASAP and post the results.

__________________
With Regards

I should mention that the fuel pressure regulator vacuum hose is connected to the regulator then there is about 8 inches of hose and then it just hangs there broken and not connected to anything.

__________________
With Regards

Should be connected to intake manifold vacuum ( BELOW the throttleplate ).
Also, when you do a compression test, do it with the throttle WIDE OPEN.

__________________
2007 C 230 Sport.

I did do it with the throttle wide open. When you say below the throttle plate, what is a throttle plate? Throttle body??

__________________
With Regards