While changing spark plugs and wires, I found a crack in the exhaust manifold. I know this needs to be replaced, but it's going to have to wait a little bit due to other replacements taking my money for now, so I'm trying to figure out if a temporary fix is possible for a couple weeks. I know leaving this crack as is for too long can cause other problems, and want to avoid that obviously, but is JB Weld or something similar a feasible temporary fix for this crack? This picture shows the crack just above the wrench.


A little back story on this truck...I bought a 1995 GMC Jimmy at the beginning of August. The guy I bought it from has only used it around his property for the last 8 years or so. It sat for about a year before he replaced the fuel tank and fuel pump before he decided to sell it. Now that it's been getting regular use, it's coming up with issues of course. It started cranking and idling rough, so we thought the catalytic convertor was clogged. Replaced that and figured out the ECM seemed to be going out, which it did later that same day(quit cranking up at all). Got that replaced and the truck cranks up and runs again, but still tries to choke out and die at idle. In replacing the plugs and wires, I realized the ignition coil needs replacing and just got the part in so haven't had a chance to put it in yet. Overall, it's a good truck. It just hasn't seen much love for a few years.

 

It doesn't look like it has been cracked for long or it would show carbon buildup on the outside from leaking exhaust gases. It likely cracked during the exhaust work. Those manifolds were not necessarily known to have issues. At least nothing like the newer LS manifolds from my own personal experience.

It is doubtful that JB weld would provide a lasting seal on the exhaust manifold, but that all comes down to proper prep & application. If you put in the time to properly prep & apply the product, you'll likely have less time invested in installing a replacement. That is providing that all of the hardware can be removed without incident. Dorman manifolds are less than $150.

 

Thank you. I don't expect any temporary fix to last very long, just a couple weeks until I can replace it. I recently got hurt at work, so paychecks aren't as full as usual right now hence the need for a couple weeks wait. Follow up question... is replacing just the cracked side acceptable or should I replace both sides at once?

 

Yes, replacing just the cracked side is acceptable. The only issue you may run into is breaking the studs on the other side if you disconnect the y-pipe from both sides. The only reason to do that would be if there is a clearance issue removing the cracked manifold and freeing the y-pipe off the other side allows for enough room to get the cracked manifold out. Muscling the y-pipe around can cause issues on the other side as well so best to be careful all around with it.