Front Main Bearing bolt leak

Jerry in Shasta

Jerry in Shasta

Senior Member
Just started a new rebulit engine. Ptoblem is the front maing braring bolts are leaking a lot of oil from under the nuts.on top.


I'm told that G.M. has a wsher that will stop the leak,. I also might try a very thin "O" ring under the bolt head.
Any idea if there ia such a G.M. washer and how/where to find.


Thanks

Jerry
 
You would have to pull the pan to install, you can't just loosen the nut to install a seal. Seem to me if you are leaking that much oil there is something else going on. Are you sure it's not the timing cover or did you/they use lock washers? The GM type might work, I would stay away from O rings. The other thing might be to use sealer around the bolt under the nuts if you go that far.
 
A possible cause for an oil leak around the exposed ends of the front main bearing bolts is the shims. If a short cut was made by slotting a shim so that it could be installed like connecting rod shim it will cause a problem like you have described . Whatever the cause the oil pan will still need to be removed . If it was mine I wouldremove the bearind cap and check the shims . It would be good to check the clearance and remove and replace any slotted shims . You will have to deal with the square heads of the main bearing bolts . there is a special socket that can be used on the main bearing bolts .
 
The socket that I got from one of the model A parts venders was 9/16-- 8 point . Bratton or Snyder will both list this socket and can be viewed on line .
 
The person that rebuilt your engine should be making this right for you. Pulling it apart yourself will probably void the warranty. What does your builder say??
 
GOOD NEWS,
It was a leak between the water pump and the head. Anti-freeze was dripping down on the bolts. The anti-freeze had a very oilly feel.



The problem with going back to the rebuilder is I'm the third owner of the engine. It has set for about 4 years before I started it


A new gasket solved the problem.


Yhanks for all the suggestions
JB
 
Good afternoon...If the builder is known, then go ahead and contact them. At the very least, they can tell you what was done to THAT engine and you can open up a relationship that might come in handy down the road...Ernie in Arizona
 
You're a lucky guy, Jerry. The fix for that is soooo easy. Bet you were a happy chappy when you foud the problem!
 
Jerry in Shasta said:
Just started a new rebulit engine. Ptoblem is the front maing braring bolts are leaking a lot of oil from under the nuts.on top.


I'm told that G.M. has a wsher that will stop the leak,. I also might try a very thin "O" ring under the bolt head.
Any idea if there ia such a G.M. washer and how/where to find.


Thanks

Jerry
Click to expand...

If you are not using lock washers, the best thing to use are flat, lead washers. 1/2 inch size. Then use a cotter key.

We some have made hundreds, out of plumbers sheet lead, for all kinds of leaks.

Tighten the nut, and easily trim the excess.

Herm.
 
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