Options for cracked exhaust manifold replacement on 2.5?

[The4bangertj]

Definitely missing the top middle bolt. If it’s snapped weld a nut to it. Don’t need to remove the driver fender. The 2.5 has plenty of room. Replacement options are a Dorman which is oem cast or afe but I’m not sold on the cost increase yet bc power is non noticeable.

I just did this two months ago. I had an oem style one that cracked in 6 months so I went and tried the afe one. I also had a cheap gasket which was also blown out so now I’m running a remflex gasket too. I snapped the bolt you’re missing and had to weld a nut to it to get it out. Without the bolt snapping it’s really an easy job. I have also been told adding a flex pipe to your exhaust will help it prevent the headers from taking the movement and will hopefully make it not crack as soon.

 

[GoldenGorilla]

Replacement options are a Dorman which is oem cast or afe but I’m not sold on the cost increase yet bc power is non noticeable.

That doesn't surprise me on power.

The 2.5 has larger exhaust ports like the earlier 4.0 heads had and the stock manifold matches those ports. Jezza's dyno test series found the same with an aftermarket header vs earlier stock 4.0L. Hopefully it holds up better.

I have the aFe shorty header for the 4.0L on a stock TUPY head. It was picked up with the intention of going to an Edelbrock head later while retaining the pre-cats and not specifically because I expected any pickup from the header. You must use either a shorty like this or an early 4.0 header with that head. The aFe has a thicker gauge tubing than any other shorty header for the later head. The cast 0331 & TUPY 4.0 manifold also has a less efficient log style with narrower runner ports. Dyno tests of this style on the 0331 head show limited peak hp gains, but some nice pick up in the middle of the rpm range. Butt dyno says... maybe.

 

[BigKID]

Definitely missing the top middle bolt. If it’s snapped weld a nut to it. Don’t need to remove the driver fender. The 2.5 has plenty of room. Replacement options are a Dorman which is oem cast or afe but I’m not sold on the cost increase yet bc power is non noticeable.

I just did this two months ago. I had an oem style one that cracked in 6 months so I went and tried the afe one. I also had a cheap gasket which was also blown out so now I’m running a remflex gasket too. I snapped the bolt you’re missing and had to weld a nut to it to get it out. Without the bolt snapping it’s really an easy job. I have also been told adding a flex pipe to your exhaust will help it prevent the headers from taking the movement and will hopefully make it not crack as soon.

I believe there is validity to adding a flex pipe. I replaced a severely cracked OEM manifold about 6 months ago with a cheap China unit. Just yesterday driving the Jeep, the weld holding the muffler to the I-pipe broke. I can only presume vibration was the culprit as the joint was not overly corroded.

As others mentioned, replacement is a fairly easy job sans any broken bolts. Mine had the forward most bolt broken since I procured it back in 2018 so it was really tempered. It was broken ~1/4" in the head so welding was not an option I wanted to try on an iron head. Was able to drill it out enough to get a tap firmly in it but would not budge so ended up drilling all the way out and rethreading.