Cracked downtube on exhaust manifold

[sreilly77]

Hey guys. On my 98 Grand Cherokee Laredo 4.0L my exhaust manifold developed a crack where the downtubes meet the collector (it is only one of the downtubes). I am a poor college student and I don't have the time nor the money right now to replace the exhaust manifold. Can I just weld the crack up for now or will this cause more damage in the future? If not, is there anything else I can do to repair this? There is a picture below that I found on the internet that shows exactly what I am dealing with. I hope there is some kind of mechanic's trick to fix this. Thanks, guys.

[reekor]

There is no problem with welding it, they always seem to crack in the welds anyways, with that said I would go over all of the welds.

Originally Posted by sreilly77

Hey guys. On my 98 Grand Cherokee Laredo 4.0L my exhaust manifold developed a crack where the downtubes meet the collector (it is only one of the downtubes). I am a poor college student and I don't have the time nor the money right now to replace the exhaust manifold. Can I just weld the crack up for now or will this cause more damage in the future? If not, is there anything else I can do to repair this? There is a picture below that I found on the internet that shows exactly what I am dealing with. I hope there is some kind of mechanic's trick to fix this. Thanks, guys.

[a_alyte]

I have the same Jeep as you & my manifold cracked last year, just as yours did. I tried using JB Weld from Autozone which goes on like paste but it didn't last too long for me. If you do use some type of weld be sure to let it dry completely, just read the instructions. I eventually bought a new manifold off ebay for a good price, I forget how much I paid off hand.

[reekor]

You should of tried JB arc weld.

Originally Posted by a_alyte

I have the same Jeep as you & my manifold cracked last year, just as yours did. I tried using JB Weld from Autozone which goes on like paste but it didn't last too long for me. If you do use some type of weld be sure to let it dry completely, just read the instructions. I eventually bought a new manifold off ebay for a good price, I forget how much I paid off hand.

[sreilly77]

yea i tried a mig weld on it and it held for a day and when that weld broke it got worse. so i went out and bought a gibson exhaust manifold to go with my magniflow catalytic converter and 40 series delta flow flowmaster

[reekor]

Mig welders are too lite duty for the thickness of a exhaust manifold. I just installed a full SS magnaflow system on my jeep, sounds sweet. Wife says its a little too loud so on her jeeps I'm gonna try a thush muffler since they dont sound too loud on my crown vic.

Originally Posted by sreilly77

yea i tried a mig weld on it and it held for a day and when that weld broke it got worse. so i went out and bought a gibson exhaust manifold to go with my magniflow catalytic converter and 40 series delta flow flowmaster

[dksob81]

Originally Posted by sreilly77

yea i tried a mig weld on it and it held for a day and when that weld broke it got worse. so i went out and bought a gibson exhaust manifold to go with my magniflow catalytic converter and 40 series delta flow flowmaster

How many amps is the MIG welder you used. A MIG should have deffinately been enough to gix your cracked manifold, This is a very common problem on the 4.0L I have repair 4 of them with a little 85amp Craftsman Mig Welder (on maximum power) amd never had a problem.