Cracked Exhaust Manifold Replacement - Gen 3

coffeegoat

Adventurer
So there appears to be about 10 different threads looking at replacement options for cracked manifolds on these trucks in various version (and the sports too!). But thus far I've only seen recommendations to try welding, or try importing Australian headers, no one successfully showing pictures of these fabled Australian units or successful weld jobs. Looks like both of mine (Gen III Lmd 2001) have hairline cracks, does anyone have a validated solution for this other than just buying replacement OEM? They're about $250 a piece so I can spend a bit and still come out ahead.
 
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coffeegoat

Adventurer
Yep, I've already got a request in to DEA Performance about they're shipping/payment etc. I'm hopeful it's a bolt on replacement because we have emissions testing in Denver, and it would suck to fail because of changing up the emissions equipment.

I've thought that brazing the cracks might be a good solution but I don't have an oxy-fuel torch and standard propane/mapp gas torches won't get hot enough. If anyone has one in the Denver area and we can experiment on my manifolds since they're already broken....
 

jeep-N-montero

Expedition Leader
Having recently replaced my passenger side manifold and about to do the driver side on my 98 I will say it is a PITA. Initially I replaced the passenger side with a Chinese version and discovered the driver side was also cracked when under the vehicle, so on Saturday I went to the local salvage yard and found a pair of perfect OEM manifolds off a 98. Did I mention it's a PITA, the passenger side took about 40 minutes to remove while the driver side took over 2 hours due to the additional parts and EGR stuff in the way. I hope to swap them over to mine in the next week or so. Do not waste your time with the Chinese junk, the casting is very rough and the runners appear more restrictive than OEM. If you strike out on the Aussie ones and can't find good used replacements local to you let me know, I could be financially motivated to scrape a few more knuckles removing another set if time allows.
 

KyleT

Explorer
From the Pajero forums the updated OEM manifolds are welded steel not cast now. No clue what that means for us.
 

jeep-N-montero

Expedition Leader
From the Pajero forums the updated OEM manifolds are welded steel not cast now. No clue what that means for us.

For the 3.5 or 3.8? Apparently the gen 3 with the 3.5 is sort of a b@stard child, seems that the earlier 3.0/3.5 engines share the same manifolds but that stopped for the Montero in 2000, sort of weird. I do see 2001 and 2002 models on occasion though in the junk yards.
 

coffeegoat

Adventurer
It looks like the 3.5 and 3.8 are very close with respect to their exhaust manifolds (and downstream as well). The ERG port is on the opposite site however. I haven't been able to find a picture of the OEM welded units yet, lots of headers though.

Here's some close up of my manifold cracks, I found a local custom muffler shop to take a look and they're pretty sure they'll be able to weld them up. I'll swing by the shop tomorrow and find out what they think.

IMAG0340.jpg

IMAG0341.jpg

They're pretty find cracks but they're definitely growing and they'll only get worse.

I'm kind of curious why they're there, I wonder if a bad ERG valve (common) could make the engine run a bit leaner than expected and hence hotter, perhaps some of that wrap insulation would help buffer the temperature swings.
 

Salonika

Monterror Pilot
Hard to say from photos.....I've had one cracked for many years. It has never gotten worse, and causes no problems. During my rebuild, I panicked when I saw it, but in hindsight, it hasn't been a problem.
 

KyleT

Explorer
For the 3.5 or 3.8? Apparently the gen 3 with the 3.5 is sort of a b@stard child, seems that the earlier 3.0/3.5 engines share the same manifolds but that stopped for the Montero in 2000, sort of weird. I do see 2001 and 2002 models on occasion though in the junk yards.

Both in gen3's? I don't know. I believe it is a gen4 piece that fits gen3.


Sent from my iPhone using Tapatalk
 

jeep-N-montero

Expedition Leader
It looks like the 3.5 and 3.8 are very close with respect to their exhaust manifolds (and downstream as well). The ERG port is on the opposite site however. I haven't been able to find a picture of the OEM welded units yet, lots of headers though.

Here's some close up of my manifold cracks, I found a local custom muffler shop to take a look and they're pretty sure they'll be able to weld them up. I'll swing by the shop tomorrow and find out what they think.

View attachment 368442

View attachment 368443

They're pretty find cracks but they're definitely growing and they'll only get worse.

I'm kind of curious why they're there, I wonder if a bad ERG valve (common) could make the engine run a bit leaner than expected and hence hotter, perhaps some of that wrap insulation would help buffer the temperature swings.

Read up on the proper procedure for welding cast manifolds and you will discover why most shops will not touch it, if not done properly it WILL crack again even worse than before. First 3 links here are great reads https://www.google.com/search?q=proper+procedure+welding+cast&ie=utf-8&oe=utf-8 I know how to weld and I wont even touch it.
 

nckwltn

Explorer
Post up your response from from the Ausie shop on shipping... I need a driver's side, and perhaps we can help each other eat some of the shipping....
 

normal_dave

waytoomuchwritinginposts.
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coffeegoat

Adventurer
Huh, I hadn't seen the advanced headers also carries a "manifold replacement" for 3 cat systems, no picture. That might be perfect for me since I have to pass Colorado emissions and I'm a bit worried about reworking my entire exhaust and then finding out I don't pass emissions. I'll give them a ping as well.
 

nckwltn

Explorer
Huh, I hadn't seen the advanced headers also carries a "manifold replacement" for 3 cat systems, no picture. That might be perfect for me since I have to pass Colorado emissions and I'm a bit worried about reworking my entire exhaust and then finding out I don't pass emissions. I'll give them a ping as well.
Im there with you on emissions.... I have to pass in California
 

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