Hello fellow wrenchers. It is time for me to come to YOU all for advice. My Monty had developed a small crack on both exhaust manifolds. I've done some searching and I don't have any luck locating new manifolds at a decent price. Funny thing is the Mitsubishi OEM parts have them for less than other sellers online. Still it is $500+ for a pair of them. I have no luck with local pull-and-save outfits - no vehicles on hand.
So, here are few questions for you:
1. Did any of you had to replace manifolds on your trucks? Where did you get the parts?
2. Do you know if there is a way to weld of braise the cracks in the manifolds? Any of you had experience with this?
3. Should I just pull the band-aid and go for $500? I intend to keep this truck forever and it is in excellent condition. No rust, no any other issues.
Thanks in advance

 

Ouch! Any idea why both cracked?

Post 19 from this thread has some pretty good info:
Welding cracked cast iron manifold

Thermosteel epoxy repair seems cheap and easy (Thermosteel has been purchased by Blue Magic. The new product name is called Quick Steel Xtreme)
Jeff Loughlin's Jeep Manifold Crack Repair
here is his original post on another forum and it was still going strong at 15 months Fix exhaust manifold crack with ThermoSteel

Here is a thread with some good pictures of a weld repair
Cracked exhaust manifold repair

Another cracked exhaust manifold thread on our Monty's:
4th Cracked Exhaust Manifold | Monterosportonline.net Forum

Here's a new right side manifold for $89
Mitsubishi Montero Sport Right Exhaust Manifold 3.0L 3.5L MR450980 ,

Here's a used left side for $69
Mitsubishi Montero Sport Exhaust Manifold Left 3.0L 3.5L MR450954 ,

 

You are the man, larry
No I honestly don't have any idea why both manifolds gave up and at about the same time. It happened over time. I thought I've been suspecting that I heard a slight exhaust leak sound on one side. Didn't expect to find it on both sided. Could it be age? Its a 2001 with almost 200k on it. Not sure...
Thanks a million for the links. I got some reading to do. Great site for used parts. I was not aware of it till today.

 

Good luck Hunter. Keep us posted. Glad to help.

 

Any update on this?

How hard to install the drivers side manifold with engine in place? I'm thinking of doing this as it will provide access to torque converter bolts via another access panel compared to the one at the bottom of the pan which was extremely difficult to use.

 

Quick update on my project.
The 2001 Montero wiht a 3.5 l engine interchanges ONLY with 2001-2006 Monteros with a 3.5 L. No interchange with Montero Sport with same engines
OEM part numbers are MR497481 and MR497482

New OEM manifolds run at $400 each
Could not find any aftermarket manifolds
No luck with any local junk yards

Talked to several metal fabrication shops in the area. One would not touch cast iron as if it was some sort of STD. Another said - we can try but it it can work or can fail miserably. No guarantees and they will not know until they start welding it. Third one was more confident and said that it is likely can be repaired (depending on how big the crack is, etc. etc.), but with welding, cooling and re-surfacing the flat part (in case of warping) need to budget for $200+ and a week worth of manifolds being off the car. Since this my wife's daily driver, this is not a very good option

Finally caught a break. Found the a more global wrecker parts search option - Used Auto Parts ? Car Parts ? Truck Parts
These guys were able to locate a pair of manifolds from a 2002 Monero with less than 100k miles on it.

Getting both of them shipped to me for under $300. It is a little more than I wanted to pay for used parts, but I think it is a good deal considering how few of used parts are out there and how unfortunately expensive OEM stuff is. I think I will pull the Y-pipe to make removing/installing manifolds easier. I plan on ordering all necessary gaskets and once all parts show up, will tackle this on one of the weekends when it is not dumping buckets outside.

I will take some picture of what's involved in this replacement and the cracks on the manifilds once get the old ones off. I'm tempted to save them and see if they can be repaired (no time pressure then). This way i can toss them into my "Montero extra parts" box and have them on hand if the replacements croak one day.

 

Well it looks like I get to unfortunately join this exclusive club as well!

Passenger side exhaust manifold is cracked between cylinders 3&5.

The pictures from this place show manifolds with the same "RS3" casting number as mine. I will call them this week to discuss
Mitsubishi Montero Sport Right Exhaust Manifold 3.0L 3.5L MR450980 ,

Several Ebay sellers offer similar product at a cheaper price but when you zoom in on the pictures, the casting number boss say "Made in China".
Exhaust Manifold New RH Mitsubishi Montero Montero Sport Montero Sport 95 03 | eBay

 

Hunter - have you gotten around to this yet? The manual gives the torque specs for the exhaust stud nuts but does not provide a bolt torque pattern.

Anyone ever see a bolt torque pattern diagram for the exhaust manifolds?

What gasket are you going to run? This link speculates that the fiber FelPro gaskets may contribute to the manifolds breaking and the consensus is to use OEM metal gaskets. My cracked manifold had a Felpro gasket on it from prior engine work.
4th Cracked Exhaust Manifold | Monterosportonline.net Forum

I have purchased a Made in China passenger manifold off Ebay for $59. Attached are pictures comparing the cracked OEM manifold with the China one. The China casting is rough but appears functional. The ports are not as round as the OEM one as evidenced by placing a gasket on the surfaces. Not shown, but the heat shield bolts on fine.

Initially I was concerned regarding the oval and jagged ports, but after comparing the cylinder head ports to the gasket, I think it will be OK as the gasket port is at least 3/16" radially larger than the head port. If this were a hot rod, then I might be a little more concerned.

The pictures were taken using the FelPro gasket but I have since purchased OEM metal gaskets part number MR281721.

 

Well, as it turns out, I took one step forward and two steps back...
Just received the used manifolds yesterday. Upon examining them found that one comes "pre-cracked" in exactly the same spot as I found on my Montero. In addition to that, both have pretty significant warping on the engine mating side. I'm returning both of them and I think I will go with the OEM. I have already purchased OEM gaskets for the engine side of the manifold and for the side that connects to the Y-pipe. Disappointed by the setback

As far as the bolt pattern for exhaust manifolds, I can't find anything specifically for Montero. The one's I've done on a different car called for going in a circular pattern, starting in the middle end moving out towards the ends of the manifold.

 

Thanks Hunter. Sorry to hear of the set back.

OEM manifolds are expensive.