when do i HAVE to change a rear main seal?

Messages
719
does it have a chance of blowing out and draining all the oil? or is that very very late?
even if it blows wouldnt the metal between the transmission and engine act as another seal so that all the oil doesnt leak out?

I would say it's very rare for one of these to leak as badly as you're worried about happening. Chances are it will continue to leak slowly for the life of the vehicle. My 05 4.8 is also, it's difficult to be 100% sure it's the rear main until you remove the transmission. Mine goes through more like 1qt per 2k miles and it's still no big deal.
 
Messages
18,142
Location
Upper Midwest
My old Accord had a leaking rear main seal, it never got catastrophic and I tried several brands of HM oil but it did nothing. I'm a bit obsessive about leaky vehicles (even with my old cars) so I pulled the transmission and replaced the thing. Nice and dry now, the only bad thing is that components under the vehicle that were previously getting oiled are now rusting. But it's worth it to get a dry underside. Probably the only 1996 Accord in all of Wisconsin that's completely oil-free underneath.
 
Messages
10
The first thing I would do is verify the source of the leak. GM 6.0 engines have several common oil leaks that are much less involved than a rear main. The easiest way to verify the source is to put UV dye in the oil. That will make it easy to pinpoint the leak(s).
 
Messages
26,408
Location
MA, Mittelfranken.de
Very unlikely. The worst one I ever saw was an old rope seal that leaked a stream of oil down the driveway when parked on a incline and even that one kept going a long time.
I usually change them though because I hate oil all over the place, its not only sucks working on it but it deteriorates rubber parts it comes on contact with.
 
Messages
5,618
Location
Ohio
I would wash the area down and then go look for the source of the leak. Might try "tweeking" the pan bolts first.
 
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