oil leak in 1990 300SL

[adiaw83]

The check engine oil light came on on my mom's 300SL the other day. When I popped the hood, the plastice cover under the engine bay looked pretty greasy. It seemed to be concentrated on the drivers side of the engine bay. The leak looks like it might be comming from a tube that led from the bottom of the engine to the bottom of the radiator, maybe an oil cooler line? Anyways how can i diagnose and fix this problem. I noticed the car also needed a new hood pad and a new tube that goes from the intake to the air filter assembly. I'm also having trouble with the soft top. Thanks for any help.

[bwheitman]

Finding an oil leak is challenging. As far as i know there is not an oil cooling unit for the 300SL, I know mine doesn't have one, but the 300 model may have. There is however a line that will go into your radiator and that is usually the transmission fluid cooling lines. There is also the power steering cooling lines, but those go to a separate cooler.
When diagnosing your problem, always ask, what has recently been done? did you have your oil changed? if so did they replace the seal in the filter cap? those are known to leak and it will look like it is coming from the side of the block. After checking that I would check the upper timeing seal, the head cover seal, and the front main seal. Those are all the seals I have had to replaced on mine so far. Also there is a tube that runs from the block to the intake manifold, it is the crankcase vacuum, that can leak oil too. Good luck!
Brian

[adiaw83]

Thanks for the response, I think it might be the oil filler cap seal because there was a little oil around there but I wouldn't think it would leak like that.

[bobterry99]

I recently bought a dye kit from www.thetoolwarehouse.net for about $55. Used it to spot a leak in an A/C system. They have other dyes for coolant and oil leaks in the kit. Highly recommended.

[bwheitman]

well, one time I changed my oil and didn't replace the seal. The oil was leaking really bad, and I kept looking and looking, I could not find the leak, it was leaking around the back of the filter case. I checked everything, but evertime I got home there would be oil on my lower panel. Finally I replaced the seal and sure enough that was it. I hope that is all your problem is, the new filter kit comes with a new seal and I was just being lazy.
Happy Benzing,
Brian