1988 10M Mid-cabin Rear Main Seal

[Scott67]

Howdy ya'll,
Anyone ever "successfully" replaced a two-piece rear main seal without pulling their engine (Gen IV 454/350)? I know the ideal method would be to pull it and then get into everything else that comes with it, but just asking if it's absolutely necessary and if it can be done.

Thanks in advance!

[BobCT]

I am definitely not a snake oil guy but this stuff has saved me on two cars, one was so dramatic it didn’t seem possible and worked long term.

AT-205. Worth a shot if the seal isn’t physically damaged.

[Scott67]

I am definitely not a snake oil guy but this stuff has saved me on two cars, one was so dramatic it didn’t seem possible and worked long term.

AT-205. Worth a shot if the seal isn’t physically damaged.

Bob, appreciate the tip. I am certainly not opposed to using it for a short term (maybe longer) if it works. It's just bizarre that this engine went from using no oil between the annual oil change to dumping almost a quart in the bilge yesterday after a 28-mile trip from St Augustine. I haven't positively verified that it's the rear seal yet, but I have checked all the other obvious locations i.e. rear side intake manifold, valve covers, oil filter housing and hoses. Just preparing myself mentally for a rear seal with the hopes that it's something less intrusive.

[Scott67]

As luck would have it (not my usual luck, but I'll take it), turns out it is not the rear main seal leaking after another op test pier side. It was that pesky little oil pressure switch (just two years old) dripping where the plastic cap meets the metal ring. Couldn't see it when it was shutdown of course, but it was leaking for sure. So, a lot easier than trying to replace a rear seal and certainly a lot cheaper.

[prowlersfish]

Well, that's good news for sure.