Oil Smoke on acceleration - 1988 560SL- - PeachParts Mercedes-Benz Forum

viperpilot99 · #1 10-23-2005, 01:43 PM

Hello everyone, after fixing my brakes from help here, I now need help with this other issue. During take off from a stoplight after some idling, I get a puff of oil smoke. This only happens after about 10 and more seconds of idling. If I rev and hold the rev no smoke. If I let it idle it also has no smoke. When I rev it, it shoots out smoke. The car has 87k miles. Could it be the valve steam seals? Any ideas?

Thanks,
George

t walgamuth · #2 10-23-2005, 01:56 PM

maybe. valve seals will leak particularly on dedelleration from high rpm. take it up to redline in third gear and back off abruptly. if they are bad you will get a lot of smoke. it is not a dangerous problem, more of a nuisance...unless you have a mosquito problem.

tom w

autozen · #3 10-27-2005, 11:01 AM

Could also be a trasmission modulator.

mike2005 · #4 10-27-2005, 11:27 AM

Symptoms point to the valve seals, but typically they do not degrade at such low mileage. Typically, valve guides and seals last much longer than 90K provided the engine has received appropriate oil changes and has not been overheated.

The 3.0 liter Mitsubishi used in Chrysler/Doge/Plymouth minivans in the 80's and 90's were notorious for early valve seal failure, but they usually lasted 100 - 120K before belching embarrasing puffs of smoke.

Not familar with your engine, perhaps others can comment on whether or not this is a problem area with that particular powerplant.

PaulSpringmann · #5 10-27-2005, 12:00 PM

I replaced the valve seals on my '86 560SL to solve this problem at 100k mi; now there is no smoke and it burns no oil. Not a bad job, just take your time.

Rockman59 · #6 10-27-2005, 12:48 PM

Mike 2005 said: Typically, valve guides and seals last much longer than 90K provided the engine has received appropriate oil changes and has not been overheated.
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My 560 SEL has had the oil changed every 3000 miles since new and I had to replace the guides and seals at 100K.....

mike2005 · #7 10-27-2005, 01:05 PM

Based on comments by Rockman59 and PaulSpringman, it appears the valve seals (and perhaps guides) are an inherent weakness in the 560 powerplant.

Rockman59 · #8 10-27-2005, 01:16 PM

I will add that even though the seals were replaced on my 1986 560 SEL at 100K....the car at that time was 15 years old. It obviously is a very low miler.....and I think years as well as mileage contribute to the wear and loss of durability of the seals. It would be interesting to hear from anyone who had to replace the seals at 100K or less on a car that was only 5 or 6 years old.

PaulSpringmann · #9 10-27-2005, 03:24 PM

My car, too, has always been well maintained, but the old valve seals were as hard as a rock. The material of the replacement seals seems to be an improvement over the original seals.

viperpilot99 · #10 10-28-2005, 01:12 PM

Very interesting! I was thinking that the valve seal problem has a lot to do with the EGR system? Do you think that the EGR prematurely kills the valve seals? Can the seals be replaced with the head on the car? I have replaced seals that way on other cars befor.

Rockman59 · #11 10-28-2005, 01:23 PM

Viperpilot99 said: Do you think that the EGR prematurely kills the valve seals? Can the seals be replaced with the head on the car? I have replaced seals that way on other cars before.
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Since my car was 15 years old before I had to replace the seals I don't think the EGR valve caused anything to be "premature". And yes, the seals can be replaced with the head on the engine.
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Two560Two · #12 10-28-2005, 01:36 PM

I have 150k on my 560SEL and the Valve seals show no sign of leakeage whatsoever and not a hint of smoke. They are still original and they will probably go sooner or later. I want to see how long they can last.

I had previously owned a 420SEL anh had to replace the seals at 140k miles.

myanoch · #13 10-28-2005, 02:28 PM

I know that my 1988 560sl used some oil
I changed the valve seals and what a difference no oil betwween changes
The old seals were hard as rocks
If the chain guides for the timing chain get hard why would not the valve seals get brittle
it's hot in the engine and it is 18 years old
Cheap fix and it works

86560SEL · #14 10-29-2005, 12:57 AM

Yeah, sounds like the valve seals. I have had a couple of cars in the past that did this. It was very embarrasing to say the least. I would dread seeing a traffic lamp turn red, because I knew the results when I would accelerate.

I was once considering a 1993 Lincoln Town Car, with 77K actual miles. It had the 4.6L engine, which are very reliable engines, but these were well known for this design flaw. It was like new and well maintained, but it already had the problem.