will jb weld hold?

[garr]

No, JB weld will not Hold...
I Don't think a weld will hold up in that spot.
New head time for you!!

 

[Rick Anderson]

I have tried JB Weld on exhaust, hoping to fill a cracked exhaust manifold for a few days until I got a new one, it didn't even last a few hours. The exhaust will burn out the JB weld in no time.

In my case, worst that could happen would be a little smoke as it burned off the manifold, in your case, exhaust is going into the cooling system and you're likely to overheat and probably do more damage to the engine.

Your going to have to remove the head to weld up the hole.

Something to consider, welds on cast iron/aluminum especially exposed to the heat of exhaust, are likely to crack again. Considering all the work to pull the head, I would definitely consider just getting another head from the junkyard.

Of course, the stories of welded up exhaust manifolds just cracking again, I'm sure are long cracks, probably NOT welded up correctly. I tiny drill hole in the exhaust port of the head is probably different, especially if done correctly by a pro with the proper wire and technique. But still, a new head would be less likely to crack.

 

[XJ Stryker]

JB weld is still holding a hole in my oil pan on my car. I wouldnt put in on a head but it works great for oil pans

 

[Rick Anderson]

I think the lesson here is, nothing will hold on exhaust manifolds or exhaust ports on the head. The exhaust at that point is just to hot and will just burn away anything that is NOT thick cast iron or water cooled metal.

Remember, it cools quite a bit after the manifold, so there are some special wraps that work on exhaust PIPES.

Steel or Aluminum Putty is NOT metal.

That hole has to be welded up with the right metal with the right technique, or it is likely to crack. I've heard of too many welded up exhaust manifolds just cracking again, to be real confident. BUT, filling a 5/16" drill hole is different than running a bead of metal 6 inches down the side of a manifold. So my guess, welding it up properly would work fine. BUT, I'm NOT 100% sure it will work with no problem. That is why I, and others recommend, investigate replacing the head with another one in as good shape.

No matter what you do, while the head is out, replace the valve stem seals, it will really keep the oil consumption down and they typically go bad after a 100k miles. Much easier with the head out to do the job.

 

[4x4life05]

I think the lesson here is, nothing will hold on exhaust manifolds or exhaust ports on the head. The exhaust at that point is just to hot and will just burn away anything that is NOT thick cast iron or water cooled metal.

Remember, it cools quite a bit after the manifold, so there are some special wraps that work on exhaust PIPES.

Steel or Aluminum Putty is NOT metal.

That hole has to be welded up with the right metal with the right technique, or it is likely to crack. I've heard of too many welded up exhaust manifolds just cracking again, to be real confident. BUT, filling a 5/16" drill hole is different than running a bead of metal 6 inches down the side of a manifold. So my guess, welding it up properly would work fine. BUT, I'm NOT 100% sure it will work with no problem. That is why I, and others recommend, investigate replacing the head with another one in as good shape.

No matter what you do, while the head is out, replace the valve stem seals, it will really keep the oil consumption down and they typically go bad after a 100k miles. Much easier with the head out to do the job.

Thank you guys for giving me lots of input! I am going to have a guy come look at it tomorrow who use to work at a machine shop to see if anything can be done, I will also be looking into what it would take to replace the head...any body have a link to a thread that explains the steps? Where can I get a replacment one? My junkyards don't seem to have many 2.5's laying around. Would the head from a dodge 2.5 work? I believe they are around the same year.

Thanks Guys!

 

[Blaine B.]

Wasn't aware it was a 2.5. But that really doesn't change things. Just makes the swap of the head a bit easier I guess since it is smaller and less heavy

 

[4x4life05]

Wasn't aware it was a 2.5. But that really doesn't change things. Just makes the swap of the head a bit easier I guess since it is smaller and less heavy

haha so true! It was a breeze to take out the intake and exhaust manifold!!! Damn parts are so freaking lite!

 

[Blaine B.]

If I were you I'd wait around until you can find a replacement head. You're going to have to spend some cash either way and the fact that the replacement won't have a patch will be worth the wait.

Plus you can scrap the old head. Although you won't get much for it...but you'll get something!

 

[Rick Anderson]

My junkyards don't seem to have many 2.5's laying around. Would the head from a dodge 2.5 work? I believe they are around the same year.

I don't think so, unless I have the motors your talking about confused.

The Jeep 2.5L I4 was an AMC Motor. It was an all iron, cam in the block, push-rods, rockers motor.

The Dodge 2.5L I4 is a Chrysler Motor. It has an aluminum head, overhead cam with a cogged timing belt.

I'm thinking the Dodge/Chrysler 2.5L that was in passenger cars, NOT aware of any 2.5L truck motors, just Chrysler Carrying over the AMC all iron 2.5L with the Jeeps.

 

[mahanja]

Yeah. I missed that it was in the actual block. Definately have to bite the bullet on this one. I was thinking it was in the headers. It'll fix a lot but not there. Time for a new head.

 

[blondejoncherokee]

dude i fixed a cracked manifold on my old scout 800 slant 4 international with this stuff from autozone/kragen whatever. its made for exhaust manifolds, i tried jb weld three times, each time it would harden into a chunk, thought it would work and didnt, it would fall off. jb welds max temp is 500*. the exhaust manifold stuff is 9$ for a small tube but its made to withstand over 1200*, i also used a big hose clamp cuz it was at the neck of the manifold. it lasted years and 200 mile each way camping trips. this stuff would work probably, jb weld will not be able to "stick" to it at the high temps.

 

[MTBracer367]

i'm not to sure how well jb would hold one of my buddies had soem on his radiator and it melted a chunk of it off even without over heating but it might not have been on a very clean surface

and another thing u might wanna check is that u didn't get and metal debris in the cylinder caus ethat could totally ruin ur engine

u might be beter off just getign a new head from the junk yard it probably won't cost to much and it'll most likely be ur safest bet