420 SEL Oil Leak - PeachParts Mercedes-Benz Forum

Hans47 · #1 01-16-2004, 05:04 PM

I have been told that the oil leak on my '88 SEL is occurring at the rear main engine seal so the transmission needs to be removed to replace the rear engine seal/housing gasket. The parts cost is insignificant but the labor involved is about nine hours. Does the entire transmission really need to be removed to access and fix the seal? Thanks in advance for the feedback.

126nut · #2 01-16-2004, 07:43 PM

It is either pull the tranny or pull the engine. Consider yourself lucky, it could be a leak from the left head gasket.

Seriously, you need to have that looked at as well, the oil can run down onto the lower bellhousing and look quite similar to a leaky rear main.

My 420 has a slightly seeping left head gasket, someday I see myself pulling the whole engine and doing a complete reseal job.

Chas

engatwork · #3 01-16-2004, 08:28 PM

Yep - engine or tranny have to be removed. While they have it apart have them go ahead and replace the front tranny seal too.

#4 01-17-2004, 01:02 AM

This is one of the reasons I got rid of my 420SEL, it had $1800 worth of oil leaks. It was a great car otherwise. In retrospect I wish I had just bit the bullet and kept it.

Hans47 · #5 01-17-2004, 10:57 AM

I can empathize with you because the same thoughts passed through my mind. In my case, the car has only 92K so I'm biting the bullet and expect it to run for at least another 100K.

Hans47 · #6 01-17-2004, 11:07 AM

engatwork, I'll speak to the tech about examining the front transmission seal during the rear main engine seal fix. He didn't mention the trans seal, but said that he would check wear on parts of the transmission connected to the axles. All of these check points make sense to me especially when doing a huge job like pulling the trans.

engatwork · #7 01-17-2004, 11:12 AM

Hans - the front tranny seal replacement is less than a 20 minute job with the tranny out. There is not really any examination necessary - just replace it. The seal is probably a $5.00 part. Getting the tranny in/out is the expensive part.

stevebfl · #8 01-17-2004, 11:13 AM

Before you do that big labor job, be double sure of the diagnosis. Its about ten to one more common for the left head to leak oil as mentioned above. The oil appears at the same place at the bottom for both leaks. The head gasket is obvious if proper attention is directed at it though.

126nut · #9 01-17-2004, 01:38 PM

Not to change the subject,

Maybe I should do a new post?,

But, I have a friend with a 380SL who is begging me to reseal his engine, it was also originally diagnosed with a leaking rear main but upon further inspection it is coming from the left head. It leaks oil like a stuck pig and I have no idea how much to charge him?? The only good thing is that the engine already has the double row conversion, should save him a few bucks. I am guessing probably about 20 hours of labor? Add a couple for broken bolts? How about the block, on my last 380 I was told to helicoil all the head bolt holes, is that really necessary?

Chas