JB Weld under exhaust manifold

[Susquehanna Squid]

I am wondering if I have to remove the exhaust manifold in order to apply JB Weld. I have a 1988 3 liter OMC and water is shooting from just under the exhaust manifold (no water in oil thank God). Upon inspection I found that the last owner applied JB Weld to the same spot. The boat did not leak much at all last year but I am pretty sure that I did not remove all of the water before I put it away last winter. I know that i have to get the old JB out of there (as much as possible) and clean it up but it is a very tight space up in there. My question is: would it be OK to just apply as much JB Weld as I can up in there or should I attempt to remove the manifold. I am not a mechanic but am pretty good with the wrenches. The existing JB Weld is on the block and the manifold and it looks like it was applied pretty thick. Also, I do not care what it looks like just as long as it quits leaking. Any help would be appreciated!

 

[frostywalrus81]

Re: JB Weld under exhaust manifold

Is there a hole is the exhaust manifold itself or just the gasket. If its just the gasket it would be a very easy job maybe no more than a couple of hours. If its the manifold I would probably look into getting a new or used one the but on. With water leaking like that it may find its way to the oil eventually. Good Luck!!!

 

[Susquehanna Squid]

Re: JB Weld under exhaust manifold

I am not sure where the hole is exactly due to all of the JB Weld in there already. But I am pretty sure that it is coming out of the block just below the exhaust manifold gasket.

 

[cooter2506]

Re: JB Weld under exhaust manifold

Pull the manifold. and get rid of as much JB as you can. Check block where the JB is it might be a cracked block instead of the manifold. But you will not know which is leaking until you get it apart. Seems to me old owner just gooped as much JB in there as he could with out removing manifold and hoped for the best

 

[PINESOL]

Re: JB Weld under exhaust manifold

yep , cooter is right .. its not much work to pull the manifold off. then atleast you will get a better look at the actual problem. who knows you may get lucky and be able to repair it for the last time . on this forum there are plenty of threads of people fixing huge cracks , my personal feeling, its just a band aid and cant be trusted. but hey you will be on the water , and i will be doing side jobs to afford the build on my 3.0 .

 

[maddog2]

Re: JB Weld under exhaust manifold

If it is a busted manifold, then replace it if possible. I bought a set of new exhaust manifolds for my 1992 4.3LX from Ebasic Power. They were listed on Ebay. Got the set for just under $300 and it came with gaskets for both manifold and risers.

I had a set of manifolds that were coated in jb weld and they leaked, then busted when it wasn't winterized properly.

good luck

 

[Susquehanna Squid]

Re: JB Weld under exhaust manifold

Thanks for all of the help! My buddy and I are taking it into his shop (he is a mechanic) this weekend to try and fix it. We are going to pull the manifold off and replace the gasket and clean off the old JB Weld so I can reapply. I will let you know how it turns out. Thanks again!

 

[Bt Doctur]

Re: JB Weld under exhaust manifold

Just make sure the surfaces are PERFECTLY CLEAN before you reapply JB.
Wash with Acetone

 

[Susquehanna Squid]

Re: JB Weld under exhaust manifold

UPDATE! Well my buddy and I pulled the exhaust manifold and found that the old JB Weld was covering 2-6 inch cracks. So, we removed the old JB Weld and used a special brake cleaning solution and some grinding pads to prep the block and manifold. We then reapplied JB Weld and added a new gasket. I put it on the muffs last night and there is not 1 drop of water! Hopefully that will be the case when I put it on the water as it should be. I just wanted to thank everyone for the help!