2001 BMW 740 Rear main seal problem

Tiny
HEIFETZ17
  • MEMBER
  • 2001 BMW 740
  • V8
  • 2WD
  • AUTOMATIC
  • 94,247 MILES
I had a leaking rear main seal. I replaced it, as well as the oil cover gasket right above the rear main. I still had an oil leak, and after doing a dye test, I confirmed oil was still coming out from around the bell housing area.

Are grooved crankshafts a common issue on these cars when the rear main wears out? Are there any other areas I can check?

Thanks very much!
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Tuesday, December 22nd, 2009 AT 9:23 PM

4 Replies

Tiny
MHPAUTOS
  • EXPERT
Hi there,

A common problem with any seal that has been leaking is that often the cause of the seal leak in the first place is that it has gone hard and and the soft presser seal is lost, when this happens and it is left for some time, the hard seal lip can wear a small groove in the seal surface, and when the new seal is fitted the lip sits in this same groove and there is far less sealing pressure or the seal can get damaged, there is a quick repair for this, it is called a speedy sleeve, this is a stainless sleeve that knocks over the seal surface restoring a good seal and as it is very thin, seal pressure is not compromised, other possible leaks may be from the rear of the sump.

Mark (mhpautos)
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Wednesday, December 23rd, 2009 AT 12:29 AM
Tiny
HEIFETZ17
  • MEMBER
Thanks very much for your help. Does the crankshaft need to be removed to fit this sleeve on, or can it be done simply by removing the transmission?

Thanks again, very much!
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Wednesday, December 23rd, 2009 AT 7:22 PM
Tiny
MHPAUTOS
  • EXPERT
Hi there, just remove the transmission and the old seal, but you best ensure that you can get one this size, not sure about the sizes you can get there, as I am in Australia things can vary here to there, an engine re conditioner should be able to give you the diameter of the crank shaft seal surface.

Mark (mhpautos)
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Wednesday, December 23rd, 2009 AT 7:41 PM
Tiny
HEIFETZ17
  • MEMBER
Thanks very much for your help!
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Thursday, December 24th, 2009 AT 1:05 AM

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