2007 S550 Bad Cylinder?!
I'm new to the forum, but I did want to get people's opinion on something. I just bought a 2007 S550, and have had it for about a month. It was from a used-car dealership, and I think I got jerked around pretty good, but that's a whole other story. So about 30 days later, the check engine light goes on. I take it to MB, and they're saying that there's no oil pressure to the #3 cylinder on the right side of the engine. Quoted me a $8K job. The good thing is that I did buy a 3'rd party warranty from the dealership.
The warranty states that the cylinder block, heads, barrels are all covered. Yet, they say if the adjuster comes out and states the cylinder head doesn't work because of negligence of maintenance or abuse, even if it was the owner before me, they won't cover it.
My question is, has anyone seen this type of problem in the engine, and what might cause it? Could it be a mechanical failure because of the way the engine was built? Car has 50K miles, not that bad, I wouldn't expect this to happen in this type of car.
Last edited by platt-deutsch; Apr 29, 2012 at 09:31 PM. Reason: spelling

I'd bet the dealer was actually referring to the cylinder compression measurements, this they can do easily with the diagnosis tool without opening the bonnet.
I hope the issue turns out to be small or will be covered by this third party warranty anyway.
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What kind of maintenance can you do on cylinder head?
even with service A, B, C & D ... the closest maintenance on the cylinder head is just oil change, is it not?
what more can you do on cylinder head?
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Go back to the dealer, and get a word for word statement from him.
Oil pressure to one cylinder does not exist. Most likely the guy said cylinder pressure, i.e. compression.
Unless they mean the oil-pressure of the hydraulic tappet; that would be reflected by the compression of that cylinder bc one valve would not open,also, that would be clearly audilble I guess.
Yes, have a good reliable MB-dealer look at it with star-diag.
Last edited by marthyh; Apr 30, 2012 at 04:47 PM.
Unless they mean the oil-pressure of the hydraulic tappet; that would be relected by the compression of that cylinder bc one valve would not open,also, that would be clearly audilble I guess.
Yes, have a good reliable MB-dealer look at it with star-diag.
Last edited by marthyh; Apr 30, 2012 at 05:05 PM.
UPDATE: MB said the return code is P-0303 which he says is a general mis-fire code for the cylinder. Since the engine has now been opened up he said it's due to a faulty exhaust valve moving around not creating a proper seal. So it sounds like the warranty company should cover it. The adjuster will be coming out in a couple of days. I'll keep everone posted. Thanks for the feedback so far!
Wow what a bunch of scam artists. Wish someone could unleash an attorney at them and screw them over with a class action lawsuit. You paid the warranty in good faith with the understanding that the deductible is all that will cost you and now they are trying to fleece you when it is time for them to pay up. Their "labor guide" is BS. You did not subscribe to some labor guide, you bought a warranty for your car to fix problems. If Mercedes claims it takes 22 hours, that is what it takes to get the car to factory standards. I'd threaten to sue them in small claims court and even follow through on that. You just can't go by some arbitrary "Labor Guide." What if their labor guide said 10 hours? They need to stand behind their "warranty" and get the car fixed for you with the $75 deductible.
This is why I'd be weary of buying any non factory warranty... I feel for you. It is ridiculous what they are putting you though.
State Farm once tried to push this Labor Guide thing on me when my car needed some bodywork after it was keyed and they did not want to pay what the Mercedes Certified body shop said would cost. I did not stand for any of the BS and got them to pay the bill of the body shop in full when they tried to get me to cover the difference between the actual cost and their "payment schedule."
Last edited by WEBSRFR; May 6, 2012 at 08:47 PM.



