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Cracked 4.0 HO exhaust manifold

2K views 23 replies 15 participants last post by  zoomin0074 
#1 ·
The exhaust manifold on the Jeep I just bought has a crack in it. The guy I bought it from suggested that I either get it welded or put another manifold/header on it.

What do you guys suggest I do? I don't want to spend a bundle of money. I've read that manifold cracking is a common occurance. Is there a solution that will prevent the replacement from cracking? The crack is where the manifold goes from 2 pipes into one pipe. Does this significantly affect performance in any way?
 
#2 ·
cheap header
I put on one of these, it has been fine so far (about 10 months). It was good quality and fit right in with no problem.

You could get it welded, but don't you need to take it off to do that anyway? If it cracked once, it probably will again, how many times do you want to take the manifold off?

Yes, a leak can cause performance problems. Cauing the O2 sensor to get an incorrect reading.
 
#5 ·
crack isnt that bad yet[/QUOTE]

That's how mine started out let it go for too long and had to do plugs, wires, cap and rotor and both O2 sensors. :(

I went to a Banks torque tube $350 or so (at least it's guaranteed for life)from TJO best price I could find might still try them til they move the shop.
 
#9 ·
Dang, I bought my Jeep in Novi yesterday, so I was like 10 minutes away from you!

The Banks manifold looks really good, but I can't afford like $400 right now. I'd be ok getting something $100 or less now that will last a couple years. What's my best option in that price range?
 
#11 ·
It's fun replacing it you have to take the intake off to get the header pipe off i unbolted it took it off the studs and used a ratchet strap from the tip of my hood in the up position to the intake to hold it up while swapping the header pipe out and I went with a stock replacement I think it was like $187 ive had bad gas milage ever since so I think im gonna replace my oxygen sensor this week. while i was at it i replaced the whole exhaust from motor to rear and put a glass pack on it. Good luck finding a header pipe and the instillation.

~Teddy~
 
#12 ·
I drove it like 3 hours home from Novi yesterday and got about 14-15mpg. I just looked at the crack again with a flashlight and it looks like it's maybe 1/3rd of the way around one of the pipes where the manifold goes from 2 pipes down to 1. Is that a bad position/size for the crack? Should I replace the manifold before I drive it much more?

So I have to take the intake off to replace the exhaust mani? Anything else I should do while I have that all apart?
 
#16 ·
I had a Pacesetter on my last Jeep, it kept coming loose. I haven't had that problem with the Banks knock-off I posted above. I was pretty surprised by the quality of the header, it's well made. I doubt it actually flows better than the stock manifold (because of the tube size), but it was cheap and has worked great.

feelsoright03 said:
while i was at it i replaced the whole exhaust from motor to rear and put a glass pack on it. Good luck finding a header pipe and the instillation.
Why did you have to do that? I can see replacing the cat and muffler, but the rest should be stainless steel. I have rarely seen them rusted out, unless yours is really old. Mine has seen the Michigan winter salt fest 11 times and is still solid.
 
#17 ·
I got one from this place www.carpartstoyourdoor.com and so far, no issues (replaced approx 8 months ago). Can be done by one person, just make sure that you align the intake manifold perfectly over the studs or you will be in for an awakening experience. :eek:
 
#18 ·
I put on a set from a 2000 and up. They changed them from one to two peices, never have to worry about it again. I paid $50 for the pair but had to get a new y pipe made. I just never wanted to do that again!

FYI the banks and borla all crack eventually too. Yes they are warrantied but you still have to change it.
 
#22 ·
Hm, I thought mine might've been cracked but it isn't, just crappy. I have a new one I bought though and have never used, although I've heard both good and bad things about the header I got. It depends on the welds I guess. If you want it, PM me and I'll send pics and stuff.
 
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