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Discussion Starter #1
Hi All,

I hope someone on this website has had this issue and was able to repair it. I have a pesky oil leak, only a few drops on the bottom engine cover. It appears that the oil is either engine or power steering, they both have the same color so it's hard to determine for sure which it is. I took the car to my local Mercedes dealer for the yearly safety inspection and the mechanic told me my valve cover gaskets were leaking. I changed them on both sides, resealed the vent covers, and replaced all of the vent hoses. I completely cleaned the engine at this time and ran the engine for at least 30 minutes while on blocks to check for any oil leaks and found no leaks. I took the car for a short drive (less than 25 miles) and there was again an oil leak on the driver's side on the bottom engine cover. I determined it was not the valve cover gaskets that was the cause of the oil leak. I then extensively cleaned and re cleaned the engine, power steering unit including hoses, the power steering pump, and A/C compressor until they are 100% free of any oil. I took the car for another short teat drive and again oil on the bottom engine cover. The only thing I have not been able to do while the car is on blocks under the front tires is to turn the steering wheel from lock to lock and see if the oil is coming from the power steering section. The mystery here is there is no tell tale signs of oil leakage on any part of the engine or other components on the engine. I have attached a photo showing the area of the oil leak on the engine bottom cover, albeit it is not a good photo it may help.Any help would be appreciated.

Thanks,

Mike
 

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Outstanding Contributor
R129 500 SL 1991
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Not easy to tell where leak is coming from looking down from top. Get it up on ramps and remove the lower engine cover and you will find the leak. Either from power steering or transmission hydraulic lines or possibly stone damage to front oil cooler matrix below radiator. To check latter quickly, run your fingers along the bottom of the front plastic bumper, on top of the bottom lip upon which the lower engine cover rests. If there’s oil here it’s probably the oil cooler. Gut feeling - hydraulic lines. The power steering line runs very close to the chassis rail and is known to rub to point of leaking.
 

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Discussion Starter #3
Thanks for the input. I have had it on ramps almost as much as on the ground looking for the oil leak(s) and cannot find it even with the engine cover removed. I think the answer lies in that I cannot turn the steering wheel from lock to lock when the car is on the ramps supported by the front tires. I think I need to support the car by the front A frames or on a frame lift so I can start the engine and then turn the steering wheel from lock to lock and then I feel I might see where the leak is coming from.

Thanks,

Mike
 

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Discussion Starter #4
I forgot to mention that when I have the engine cover off there is no visible oil leak present anywhere on or around the engine, power steering pump, power steering lines, or A/C compressor. I feel the oil is leaking when the power steering system is loaded up during normal driving and turning the steering wheel from left to right. Even after that there is only a minor amount of oil on the engine cover, a few drops at most, but it spreads out to look like more. At this time it is more of an annoyance than a concern so I may just have to live with for now until it get worse and the source of the leak becomes apparent.

Mike
 

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Discussion Starter #5
I have attached additional photos of the underside of the engine compartment and the inside of the engine cover showing the location of the oil leak. The oil leak always forms a drop or two on the adjusting bol
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t for the A/C compressor, no where else.
 

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Discussion Starter #6
More info on the oil leak issue with my 19099 SL500. I have discovered where the oil is leaking from. It is "seeping" from the very bottom timing chain cover bolt on the driver's side. I assume that this bolt goes into a through hole that is tapped into the inside of the block and it is not a blind hole. Actually the lower bolt on the passenger side is also "seeping" but not enough to cause a drip.What type of sealer did Mercedes use to seal these bolt at the factory?
 
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