Oil leak from the rear seal 420 SEL

Is there any way of patching an oil leak from the rear seal on my 420 sel without having to replace the seal?

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No good way.
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While I don't recommend it since I have since found that it creates a dependancy, using high mileage oil for the past 2 years and 15000 miles (you know, those ones that say they are for cars over 75000 miles. I mostly used the valvoline version, but sometimes used the castrol version), made my rear main seal stop leaking (380SE). However, I don't think it's worth it since it makes you dependant on those oils. Also, unless you're leaking like a quart a day, don't bother replacing it. Mine had been slow leaking for about 9 years, never got any worse. Richard
said:

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marlinspike wrote:

When you had the oil leak did you get a burned oil smell in and outside the car? My car is leaking a very small amount of oil, but what bothers me is the burning oil smell. Unless there is a hole in the exhaust pipe...
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Richard Smith wrote:

Is there any other problem using this type of oil besides dependency?
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I had no oil smell in and out of the car. I did have a raw gas smell when I floored it, but that was because of old injector seals. As far as the oil, AFAIK there is no downside other than dependancy, but dependancy kinda sucks since it's only available in 10-40, 20-50, and then some other weights that are no good for our cars. Richard
said:

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As far as that smell, also check that you don't have a gas leak at the lines at the fuel filter. I don't care to recall how long I was driving around with a serious gas leak right near my exhaust. It gave me a raw gas smell inside and out. Richard
said:

420
outside
the
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Nope.
You have to tear into it to replace it. And guess what happens then? It leaks!
Seals rarely fail, compression blowby forces the oil past an otherwise ok seal.
Not exactly what you wanted to hear, huh?
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Richard: What is the ultimate fix for a leaky seal?
Larry
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On 2005-02-07 07:57:58 -0800, snipped-for-privacy@aol.com (Boelkowj) said:

If there's nothing else wrong with the engine, replacing the seal will fix it. If there is an over-pressure situation inside the engine itself, then replacing the seal is a waste of time.
However, if the leaking was caused by an over-pressure situation, then the rear main seal shouldn't be the only leak. you should see other leaks at other key junctures...
Look around carefully, if this is the only leak you see, then the odds are you can replace the seal and it will fix it.
Marty
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Replacing the rear main seal is $1800-$2200. Not worth it. Richard
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Not worth it at that price...
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Maybe, but I've seen just the rear main leak, maybe it goes first.

Test and measure: do a compreession check.
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Just the rear has been leaking on my 380 for 9 years. Richard
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Fix the compression blowby. Usualy it's just the head(s) or rather the valve guides
A leakdown test will tell if if there's compression gasses getting past the rings (reasonably unlikely, but you do need to check it).
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No! The tranny must come down, the flywheel has to be removed from the back of the engine, and then the old seal is removed, the "seat" carefully cleaned, and the new seal inserted correctly. Most "shops" insert the seal by lubricating it and taking a large socket and pushing it into place. The Mercedes dealer has a special tool designed for evenly seating the new seal. Which is why they guarantee the job for a year. They usually give a package price since they need to drop the tranny anyway, they replace the front seal on it in addition to replacing the crankshaft seal ("rear main seal"). P.

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