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1988 Mercedes Benz 560 SEL
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4 Posts
Discussion Starter · #1 ·
Throughout my two years of ownership, I have been aware that my 560 leaks oil. You can tell every space my car has been parked in because of the stains. For every long/highway trip I go on, I notice that the oil level falls incrementally on the dipstick. Moreover, during and after every long trip or hard driving, there is the omnipresent scent of WD-40 sizzling on the exhaust and cats; occasionally, there is even a slight plume of smoke that rises suspiciously from beneath the hood. I have been told that it is a "common problem on older Mercedes", and that "repairing it would cost more than the car is worth". I do not doubt either of these statements, and suppose I could leave it be for another several thousand miles or more (currently have about 138,500 miles) before addressing it. Yet I was recently faced with the grim reality of the situation when I took my 560 in for an oil change, and observed that most of the underside of the car, including the floor pan and exhaust system, was coated in oil from it streaking back from the leak during fast driving. Duh. But this sight and the constant smell of burning oil immensely bothered me, so I began doing some research into a DIY project to replace the two main areas I believe to be the source of my leak(s); the engine rear main seal, and the automatic transmission front seal. I have been told that the leak is at the head gasket (?), but I see no evidence of this as it appears that the leak occurs only where the engine meets the transmission. I would like to know more about how I can go about replacing the seals myself, as I would certainly save a ton of money by doing so, and am absolutely through with dubious Mercedes mechanics. I am somewhat familiar with the procedure to get to both seals, yet I am not entirely clear. If anyone can provide me with technical support or online shop manuals, it would be greatly appreciated. I will try and get some pictures of the leak situation as soon as I can.
 

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CH4S Admin , Outstanding Contributor
1985 500SEC, 1991 190E 2.6.
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45,175 Posts
Have you replaced your valve cover gaskets? If not - do it.
+ 1. That should be the first step. The 'Welcome...' announcement / tutorial on top will help to locate the many threads in the forum archive etc.
Cheers
 

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1993 300TE, 1995 E320 Wagon
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1,895 Posts
Yup-- I was going to say "valve cover gaskets" too. They often leak at the rear of the cylinder bank, and a cursory inspection would make it seem like the rear seal. I'd definitely have a real close look at the top of the engine right in front of the false firewall. Also have a look at the oil pressure sending unit, below and behind the oil filter housing. Mine had a slow drip there for a long time, with the same smoke/smell symptoms. Very slow leak (oil level never went down more than 1/4 quart over 3K miles). Yours is more serious, obviously, and the VCGs are the prime suspect(s).
 

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'90 560 SEL RUF 42,000m, '90 560 SEL RUF 56,000m, '90 560 SEL RUF 150,000m '90 560 SEC RUF 225,000m
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12 Posts
Yup-- I was going to say "valve cover gaskets" too. They often leak at the rear of the cylinder bank, and a cursory inspection would make it seem like the rear seal. I'd definitely have a real close look at the top of the engine right in front of the false firewall. Also have a look at the oil pressure sending unit, below and behind the oil filter housing. Mine had a slow drip there for a long time, with the same smoke/smell symptoms. Very slow leak (oil level never went down more than 1/4 quart over 3K miles). Yours is more serious, obviously, and the VCGs are the prime suspect(s).
Chipping in my two cents; every time I've had smoke from under the hood, it's the Valve Cover Gaskets weeping gently onto the exhaust headers. I've had a 380 and two 560's do this, all around 130,000 miles (just before they start crying for valve guide seals to be replaced). The 380 was exactly as you describe; underside smeared in oil and drips from bell-housing. All from VGG's.
 

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1988 Mercedes Benz 560 SEL
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4 Posts
Discussion Starter · #6 ·
Hmm... not the first time I've been suggested that the problem lies with the VCGs, but I never thought of taking a closer look at it. I will certainly look into it now, thanks for the pointers.
 

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1983 500 SEC Lorinser 1971 280se w108
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1,963 Posts
Also when the valve covers are off its a great time to check your cam chain and guides
I bought new valve cover gaskets and when I pulled the covers to fit em discovered my cam chain had streached my guides were brittle and saved myself major heart ache by doing the lot at the same time :)
 
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