uh oh, low compression
 

I've been on this forum before recently and was given excellent advice. Well, following them I had a compression test on my '03 w211 E500. Cylinder 8 was extremely low, but that was all the shop I took it to could tell me. Umm, what does this mean and what are some of the causes and what are possible remedies? It has 140k miles on it and otherwise runs well. As usual I thank you in advance for any responses...

Seems odd, I'd have the test re-done, and perhaps diagnostics to see why it'd be so low. There could be another issue.

Wait, this in followup to your earlier post on a Nr 8 misfire the got better with Gumout.

Assuming you have no oil consumption issues, the low compression might be related to a valve that isn't sealing correctly because of deposits ont the face or seat. It'/s not common, but we don't know what kind of gas you've been pumping through these last 140K miles.

You want a Leak-Down test done on that cylinder....that will tell you what/why...
I would expect that they did one after seeing low compression, so I would ask that exact question. If they did not do one , they are not thorough techs.

Thanks everyone for your support. I've only used premium unleaded fuel from "quality" stations. I've only used the synthetic oil recommended from the manufacturer; that's what's so puzzeling to me. I've followed everything to the letter and was expecting for this car to last much longer without these kinds of issues. As far as the oil consumption issues, I have been addidng at least a quart a month, but I do a lot of highway driving. lately it has gone up to a quart every two weeks...

If your problems aren't solved easily, which it doesn't sound good, its probably time to sell... Take it to Carmax and they will give you wholesale for it, and you won't have to divulge the little motor issue. ;)

I would probably be cheaper to sell it and buy another one rather than buying a new motor.

I think Carmax checks compression. Anyway, it's a little early to bail. Low compression has 4 possibilities:
1. Worn, broken or stuck rings
2. Stuck open valves
3. Leaking headgasket
4. Cracked block

(Or loose 2nd spark plug in the case of 2-plug engines like yours)

Only number 4 requires a new engine, and it's extremely unlikely. Like Arthur said, the shop should have told you the next steps they need to take to isolate the cause.
It won't be cheap, but way less than a new engine.
BTW, only Chevron, Texaco and Shell use additives to combat top end gunk buildup. The others just specialize in excessive profit, whatever your cost.

With your oil consuption increase, I would suspect a broken ring...again, a leak down test ...

I agree that he shouldn't give up yet, but I KNOW that carmax doesn't check compression because I worked there briefly right out of high school. The buyers office inspects the vehicle in the parking lot checking the oil and fluids, look for exterior and interior imperfections, and take it for a drive. That's it...

A friend of mine got 4 grand for a basically worthless 4 runner with a huge oil usage problem. As long as the car makes it on and off the dealer auction block, they don't care.

Once again, thanks everyone. Someone just mentioned to me a couple hours ago about the rings once we pulled the plugs on cyl 8 and found oil on them. Is a broken ring difficult to repair? I've done a lot of things, but never ventured into the INSIDES! Also thanks for the heads up on the different gas stations!

for your oil consumption problem I would suspect valve stem seals, most likely what is happening is the oil leaving deposits on valves which will cause them to not seat well, this will give you low compression. Oil seals will crack over time from the heat I would suspect that is your problem for the oil comsumption. Your milage is low on that car to have ring problems..replace the seals with use of chevron gas should restore compression in cyclinder..
Bob

Thanks Bob. In your last statement, you said to replace the seals, use chevron gas. Does that mean that I just have to use chevron gas and all will be well? And if that is the case, is there some additive that maybe I can use also? Thanks in advance.

Like I said..you want to know what's up, the next test is Leak Down test.
It is a 5 min, simple test that tells you where the leak is...simple.


And as far as rings on 113 engine with that milage go, do a search and read up on what some of the Forum's Benz Techs [ who work on these all day. every day] have to say about 112/113 engines and ring complaints... .. Common , even under 100K. .
Here's a credible one........

<It sounds like the piston rings are sticking. It's not uncommon for M112/113's. My shop re-rings about one or two every month to resolve oil consumption complaints. Before we tear them down though, we perform a borescope inspection of the cylinder walls. Every now and then we find severe scoring. In these cases we replace the engine block with a set of fitted pistons. >
__________________
ILUVMILS
MB Master Guild Technician 2007
MB Shop Foreman
MB Master Technician
Same dealership for 20 years!

Ok, a leak down test. I'll have it done withinnext 2 days and post the details as soon as I do. Thank you. Boy, I hope it's not the rings, sounds expensive...

Yes , that would be a big ticket item..
As all the post have stressed, you have low comp and the cause can be from any/all the mentioned possible failures..
And a correct diagnosis can not be done w/o further testing...you can put any kind of gas in there you want, but you want to know the cause of the problem.
My mention of a possible ring condition is simply mentioned as a SUSPECT b/c of that known , common problem on THAT engine, and your complaint of low comp and oil consumption fits that possible.... it is NOT a diagnosis..it is something that shoud be checked out with a further test in order to make a correct diagnosis.
Hopefully it is not the cause of your condition, but don't let anyone tell you that 113 engines don't have ring problems at that milage ..cuz they do.......................