Topic: exhaust manifold cracked after 5k miles?!?

[4banged]

I replaced my cracked exhaust manifold on my 03 2.4l about 5k miles ago and when I was replacing the O2 sensor today I noticed that the new exhaust manifold already has a crack! I bought it off eBay because the dealer told me they couldn't get me one and to try eBay. I intalled it properly with the metal gasket and torq on bolts so i don't know what to do...don't think I can have it welded because its forged and I don't think anyone makes a performance one for the 2.4?  Anyone have any suggestions?

[Jeffy]

Hmm, haven't heard of issues with the 2.4L.  It should be a smoother running engine then the 2.5L.  I would think the exhaust manifold is nodular cast iron though.

Where is it cracking?  At 1 or 4?

[4banged]

I've seen some other threads on jeepforum with people having this cracking problem with the 2.4 but I really thought I would get another 100k before I had to worry about it again. It is a smooth running engine. . . thing barely vibrates. The original one cracked in between every pipe, the new one has a crack inbetween 3 & 4. It almost looks like the weight of the downpipe might have caused this crack. . . all 4 pipes gather at the back (4) where they form the one pipe and bolt to the downpipe. . . when you look at the crack it almost looks like it's being pulled apart but who knows. I haven't even done any offroading with it so this is just street driving.
Maybe I'll call the dealer tomorrow and see if they have any ideas . . . there's also a custom muffler shop that I could talk to about possibly running some welds inbetween? Frustrating.

[grumpygy]

I've seen some other threads on jeepforum with people having this cracking problem with the 2.4 but I really thought I would get another 100k before I had to worry about it again. It is a smooth running engine. . . thing barely vibrates. The original one cracked in between every pipe, the new one has a crack inbetween 3 & 4. It almost looks like the weight of the downpipe might have caused this crack. . . all 4 pipes gather at the back (4) where they form the one pipe and bolt to the downpipe. . . when you look at the crack it almost looks like it's being pulled apart but who knows. I haven't even done any offroading with it so this is just street driving.
Maybe I'll call the dealer tomorrow and see if they have any ideas . . . there's also a custom muffler shop that I could talk to about possibly running some welds inbetween? Frustrating.

Unless they really know how to weld cast they will just make it worse.  I would look over your exhaust system make sure all the hangers are in good shape.

[sharpxmen]

i welded the one on my Camaro driver's side tig with stainless filler rod and never had it crack again, it can be done. deep chamfer and about 4 passes, needs to be kept red hot (no pauses between beads) so it will not crack

[Wheezer]

Just to reveal my ignorance a little, but isn't that the same engine as the Neon? Should be a ton of performance gear if it is.
Wheezer

[sharpxmen]

Just to reveal my ignorance a little, but isn't that the same engine as the Neon? Should be a ton of performance gear if it is.
Wheezer

if you're thinking of the turbo there are differences and not exactly the same.

[4banged]

Just to reveal my ignorance a little, but isn't that the same engine as the Neon? Should be a ton of performance gear if it is.
Wheezer

It's the same engine but the neon and the pt cruiser have the engine horizontally and the wrangler has it straight back (forgot term), so any headers or turbos would need to be rerouted. I wish it was that simple to throw a turbo on...i'd be at the wreck yard scavaging.
Surprised no one on here has run into this ... Where are my 2.4 people?

[Jeffy]

It's the same engine but the neon and the pt cruiser have the engine horizontally and the wrangler has it straight back (forgot term), so any headers or turbos would need to be rerouted. I wish it was that simple to throw a turbo on...i'd be at the wreck yard scavaging.
Surprised no one on here has run into this ... Where are my 2.4 people?

It's called N/S as opposed to transverse/horizontal.

One thing to check is to see if the down pipe has tension on it or if it's relaxed.  If it has tension, then that tension with the heat and engine vibrations can cause cracks in the exhaust manifold.  That's usually the cause of most exhaust hanger issues.

Art has two 2.4L's dut I don't think he has any issues.

I'd have someone weld the manifold.

[4banged]

UPDATE: I called the eBay store that sold it to me and they're actually going to honor the warranty even though its been more then the 12 months (bought it last November and its not my daily driver so only 5k miles). All I have to do is pay $15 return shipping.
Jeff, I'm definitely going to check out the tension of the exhaust when I hook this one up and adjust hangers if needed so thanks for that suggestion. I'm also going to put some locking washers on where it hooks to the exhaust because I'm contantly retightening the damn thing.

[reddogg]

would a flex exhaust pipe like the one in the link help with cracking? I too have a cracked manifold which I have welded twice. Seems as though this is a common issue.
 http://www.autozone.com/autozone/accessories/Bosal-2-in-i-d-x-10-1-2-in-length-flexible-exhaust-connector?itemIdentifier=424715

[4banged]

would a flex exhaust pipe like the one in the link help with cracking? I too have a cracked manifold which I have welded twice. Seems as though this is a common issue.
 http://www.autozone.com/autozone/accessories/Bosal-2-in-i-d-x-10-1-2-in-length-flexible-exhaust-connector?itemIdentifier=424715

I bet it would relieve some stress ... Now that I think of it, my other vehicles all have one of these flex pipes stock...maybe there's one further down the line but I don't remember seeing one?

[grumpygy]

Would not use lock washers on Exhaust.  The reason is they actually work loose with each heating and cooling.  Learned this while building heavy Equipment.  We found that correct torque worked better.  If you use anything use a Lock nut not a nylock but crimp lock.  Also only use them once, take it off again and use new nuts.

[Jeffy]

Would not use lock washers on Exhaust.  The reason is they actually work loose with each heating and cooling.  Learned this while building heavy Equipment.  We found that correct torque worked better.  If you use anything use a Lock nut not a nylock but crimp lock.  Also only use them once, take it off again and use new nuts.

Yeah, my #1 cylinder bolt for the exhaust manifold always works it's way lose.  I'd rather have it lose then crack something.

Flex pipe might help.  Just make sure you get a quality flex pipe as they tend to lea if not.  Also, not using rigid engine mounts.  That's what killed my exhaust hangers a few times.  Making sure the hangers aren't under tension also really helps.  This is why I like bolt-on exhausts as well.