I just ran a compression test on the engine of my 1982 280E, and I was wondering if the results are ok. All cylinders tested right around 10, but cylinder 3 and cylinder 6 tested at 11. Is this a problem? Thanks, as always, for the advice.

What kind of compression gauge are you using. 10 and 11 make no sense to me. Can you tell the compression in PSI

The generally accepted rule of thumb is; all cylinders within a 10% range. You're right in there. Is there a problem with the engine? Typically a compression test is done to diagnose a problem.

Good luck,

280e compression
 

I was using a metric gauge. It says that the numbers are in 10X100 kilopascals, the 10 is approximately equal to 145 psi and 11 is approx. 160 p.s.i.

The results don't look bad. Just be sure you are consistent when doing the test. Mercedes-Benz has always said "eight revolutions of the engine" on each cylinder. That works out to four needle movements of the gauge for each cylinder. Also, make sure the throttle is open.
Regards,
Randy D.

Thank you but I'm not a Yank. Im southern born and southern bred.

I was reading all of your posts about compression and I just had mine tested. They tested it wet and dry. It seems that the #1 cyclinder was at 25psi dry and 100psi wet. All of the others were around 145-150. I was told that the piston ring must have broken and that I needed to get a whole new engine. How does that sound to all of you? Can't I just have the head taken off and the ring/rings replaced or is that just as costly. Thanks

Thanks for the quick reply.

My car has been running great until yesterday when I exited the freeway and stopped at the light. My car started to idle really rough, in fact the engine was shaking so bad that the whole car was rocking. When I went to accelerate from a stop, I had no power at all until it got up to 20mph and then everything was fine until I slowed down again. Luckily my house was just around the corner. The car in question is an 86 300e with 135,000 miles. Isn't it rare for a piston ring to just break? I would think that I would have noticed it slowly getting worse if it was just worn. Could it be anything else that I should have checked out first before I opt for a tear down or replacement?

Thanks again.

Stan Pittman,

What a great reply to the Yank comment!

I think hanging on with the English system is our last ditch effort to prevent world government.:)

Relax everyone, just a joke!:)

Have a great day,