SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: ka0tyk on May 05, 2014, 10:58:37 AM
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i have a feeling my rear main is leaking... my oil pan is new, new gasket, blah blah and im getting a tiny little drip near the rear of the motor. even when its off. nothing crazy but enough to make me put a towel in the bilge to catch it and enough to make a mess. i cant really see where its coming from as the mercury bellhousing blocks most of my view.
is the rear main like a 2 piece deal that sits in the rear cap of the block? how do i get the old first piece out and a new one in without pulling the caps and the crank?
(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fimage.carcraft.com%2Ff%2Ftecharticles%2Fccrp_1207_chevrolet_454_blue_collar_build%2F37525901%2Fccrp-1207-chevrolet-454-blue-collar-build-20.jpg&hash=7e57a460a26b1f6e6dc111857285e3e169ec0a1e)
also is there a "marine use" rear main seal to go for or are they all pretty much the same?
would i be better off just pulling the motor out and doing a freshen up with new bearings, etc? general ideas on the cost for that? machining the block fresh, hone, rings, etc.
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U'll have to pull that main cap to fix it! Sorry for the bad news but it's the only way to fix it correctly!
You might want to make 100%sure that's ur problem I've seen where ppl have put way too much oil in and that caused leaks! Not saying that's the case here but I would pull the motor to get a better look. Good luck! Hope you can correct the problem soon as summer has just begun!
Sent from my iPhone using SoCal Jet Boats
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If it is a Mark IV it has a two piece rear seal like the pic you posted. If it is a Gen V or Gen VI it has a one piece seal.
For the two piece seal it's not hard to replace once the engine is on the stand. You don't need to remove anything except the rear main bearing cap (as pictured), the 1/2 that is in the block will push out with a little effort and slide right out once you can get a hold of it.
THIS IS THE IMPORTANT PART: The new seal should come with a little plastic film tab with rounded edges that you need to place between the back side of the seal and the block before you push the seal into the slot. Without the little guard tab you will scalp a sliver off the back side of the seal that is very important in getting the correct pressure on the seal surface. Get it?
The alternative is to break out the credit card and have it all gone through.
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If you have a 2 piece seal, don't install it like the picture. Push on side farther down so the other side sticks up 3/4" or so, this offsets the seal seam and the block seam. Use black Toyota FIPG sealant on the mating ends of the seal halves and at the specified points on the main cap and shit won't leak