289 engine rear main seal leak

callbald

callbald

Senior Member
Has anyone tried any of the engine additives to swell gaskets to stop leaks. I realize replacement is preferred. I would like to make it through the summer and do the work this fall so I can enjoy driving it for the rest of this summer.
 
i dont know if your 64 has a pcv valve or not if it does it has to be hooked up and working or the seal will leak.
 
I've tried them all, there is no magic fix in a bottle!
The only way to stop an oil leak is to install new seal.
Drive your car as much as you can and enjoy it.
 
Well replacing the rear main seal I found a real mess. it Took heck of an effort to get out the 1/2 seal above the crank. It was loaded with black RTV. I spent a couple of hours running fine brushes in the bearing slot to get the crap out. Wouldn't you know it, the NEW Felpro main seal leaks. Who ever loaded the old seal with RTV knew something I didn't. All I can do again is lift the engine and try another seal....ANY SUGGESTIONS WOULD BE APPRECIATED. Thanks Rob
 
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Does the crank have a groove worn in? Did you stagger the parting lines? I've been lucky so far. Never used more than 1/16th bead of silicone at the corners of cap and rear edge of cap at parting line. Sorry I don't have an answer for you.
 
Crank does not have a lap groove worn in. Yes the seals part lines are staggered about 1/4 inch and the ends siliconed as well was cap corners. All I can think of is some material is still in the bearing OR there is a manufactured problem in the upper seal area. Maybe I should silicone this one too.
 
As mentioned, make sure the pcv system is operating properly. If not, the crankcase pressure (blowby) has to go somewhere and a rear main seal is one of those places. Are you sure the rear main bearing and crank are within tolerances? If it's not, it'll be tough to seal. I assume you are using a neoprene replacement seal and not another rope and that you removed the original steel pin in the main cap that would keep the rope from moving. That said, you mentioned staggering the seal, and you did install it the correct direction, sharp edge towards the front. A suggestion is that you don't get carried away with the silcone, a small film on the outside and just a tiny dab on the ends. Too much and it will cause the seal edge to not flex properly and the oil will pass thru.
One last thought, are you sure it's the main seal that's leaking and not the rubbber seal at the rear of the oil pan?
 
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