View Full Version : When to reseal case halves?

04-30-14, 06:37 PM
I know this is hard question to answer since you can't see the engine however I must ask. My engine is in an engine stand with the heads and oil pan removed. I am in the process of cleaning the valves, piston tops and installing 20 time serts. I read the post "Case Halves Reseal... FWD RTV Sealant Procedure with Current Oil Distribution Plat" and feel that I may very well screw up the procedure of resealing the case halves. My engine was covered with oil and I was unable to determine the source or sources of the leaks. Are oil leaks at the case halves that common? The process calls for GM P/N 12378521 sealant. I saw other posts that recommend Permatex Ultra Gray for the oil pan and assume this RTV would also work for the case halves. As you can tell I really don't want to split the case but I also really don't want to drop the cradle again. Your thoughts would be welcome on this question or comments on anything else I should do while the engine is in the stand.

04-30-14, 06:49 PM
Half case leaks are usually just seepage or slow drips. Normally, we tell people to live with it, since fixing it is costly because of the labor involved. You can buy a lot if oil for that price.

Since your engine is out, I'd say go for it unless you think you'll mess it up.

04-30-14, 08:56 PM
Always consider gravity. If there is oil above the half case line, it may be the cam covers.

04-30-14, 09:01 PM
Remember the costs go up, new rod bolts IIRC and are not cheap. I'm not touching my half case when it comes out. The half case may be seeping a bit, the rear main will get changed though.
refer to Bill Buttermore's head gasket thread for all that was involved and costs.

04-30-14, 10:25 PM
if at all wet I would reseal while the engine is on a stand. You don't need new main bolts the rod bolts are one time use as the factory service manual says. The only thing that is costly is the rear main seal installer. The oil plate is not very expensive.

05-01-14, 07:51 AM
rod bolts aren't removed unless you're taking the pistons out.. main bolts can be re-used. they are not torque to yield.

05-02-14, 03:41 PM
its really not that hard to re seal the half case, just tip of advice, if you take you flywheel/flex plate off when you go to re install the flywheel put a little RTV on each of the bolt threads, they are through to the other side, and cause cause slight oil seepage, the extra 2 min and $0.25 of RTV sealant definitely worth it.


put a piece of tape or somehow mark one of the little bolts that holts the oil pick up down, 10mm head, that one is very slightly longer than the rest to account for the thickness of the oil pickup mount.

05-03-14, 02:07 AM
Not difficult to reseal the halfcase like stated above. There are less to screw up, I think the most important(and difficult) part is to not block the oil passage.

I used permatex high temperature thread sealant with PTFE for the flexplate bolt threads.

05-03-14, 02:17 AM
Thanks for all the tips they will add to my facts when I decide.