Cracked exhaust manifold on a 4.0L?!?

K-Phat · #1 (**permalink**) 10-13-2003, 03:25 AM

OK so I just picked up a copy of the Nov Four Wheeler mag and they have a section on upgrades and one of them is about upgradeing the exkhaust manifold on the 4.0 Jeeps. They say that the engines have a design flaw(s) and that it almost guarantees failure at some point. They even said that one of their project Wranglers blew out the manifold at just 48,000. The thing I want to know is if anyone has ever had this happen to them before or heard about it before. Plus if this is true shouldn't Jeep do a recall on there 4.0s? Now that I've read this I'm now thinking about upgrading my manifold instead of getting a winch :?

Bounty__Hunter · #2 (**permalink**) 10-13-2003, 03:43 AM

It happens on most of the 4.0L engines. A friend of mine complained to DC Customer Service enough that a dealership changed his out for $50 out of pocket.

They can be welded, but should be professionally done and oven-tempered to prevent more cracking. Find a welding shop that has a lot of experience welding manifolds, especially boat manifolds since they crack more often.

K_K_PSI_GUY · #3 (**permalink**) 10-13-2003, 03:56 AM

How can you tell if the manifold is cracked? Does this apply to the 4.0 YJ's as well? I bet DC will blow it off as just a common problem with Jeeps.

Matmadus · #4 (**permalink**) 10-13-2003, 02:21 PM

My cracked two weeks ago and now i have to do a repair with like next to no money, so i'm going to replace it with SS Headers and just fix the problem for a while.

jaketime81 · #5 (**permalink**) 10-13-2003, 05:14 PM

My exuast manifold cracked at about 75k miles. you can hear the air coming out of the crack while the engine is running, its especialy loud with the top on. I took it out and had a welding shop fix it up. took about 3 hours to get it out and 3 more to get it back in.

Dont do what I did, It was fixed for a while than cracked again. Best thing to do is Replace it. I now have to take it back out and buy all new seals (again) for my new one. Any suggestions on a new header brand, I was looking into Borla or Gibson, but im not sure.

jeepdude832 · #6 (**permalink**) 10-13-2003, 11:07 PM

Banks Torque Tube 399.00 Well worth it wont crack nice torque gains. I put this on mine the week I bought my jeep. Dont repair it it is a waste of time. It is sorta difficult to install if you dont know what to do. I had my dad to help me. Make sure you seel up the gasket right or you will have a vaccum leak and you will idle at 3000 rpm

K-Phat · #7 (**permalink**) 10-14-2003, 01:23 AM

Hey guys thanks for the quick replies. Sounds like this does happen to the 4.0s. Guess I will have to put the winch on hold for a bit. Four Wheeler mag suggested going Borla in there article and that is the way I think I'm going to head. In their article they said it takes between two and three hours to change out. Later.........