Any write-ups on removing exhaust manifold on 2.5L?

[MississippiComanche]

Just thought I'd get to see if there are any write-ups for this before I get started this week. I searched the site and I couldn't find anything specific to the 2.5L. 

[89 MJ]

Not that I know of. What are you looking to find out about it?

[eaglescout526]

Ha! You aren’t removing that easily. You have to unbolt both manifolds at the same time, unbolt the pipe at the connection, unplug everything and remove the fuel lines(do this at the quick connect to save you some time) and then to separate and replace the exhaust manifold you have to unbolt the EGR tube and the two should be separated from each other. It’s not an easy job. Unless your manifold is trash, cracked and causing issues, drive it. 

[cruiser54]

^^ Yeah. Getting the bolts out is the easy part as they're usually broken off or missing. 

[MississippiComanche]

Yea the main motivation behind me wanting to do it is a suspected exhaust leak near the manifold. Sounds louder by the engine than it used to and I smell exhaust/gas in cab every time I run the truck. 

 

Just trying to identify all possible sources of the smell. 

[eaglescout526]

I’d look at the rest of the exhaust before pulling that manifold first. Only because if you do pull it, you’ll be down the MJ for a day or two. Has the floor been repaired? 

[Salvagedcircuit]

This guy just did one on his comanche, but he is very much a novice with the 2.5 and is learning a bit here.

 

https://www.youtube.com/watch?v=NtCUx2c4TJ4

[gogmorgo]

You should be able to see cracks without pulling it off. If you just need to change the gasket you should be able to just unbolt the manifolds and move them away just far enough to scrape the gasket surfaces and slip in a new gasket, without disconnecting too much else. Unless the 2.5 intake is bolted to the power steering pump the way the 4.0’s is, I don’t remember, but that’s a few extra steps if that’s the case. 

[eaglescout526]

9 hours ago, gogmorgo said:

Unless the 2.5 intake is bolted to the power steering pump the way the 4.0’s is

I spaced that, it is bolted to the manifold. 
And if there’s cracks on the exhaust manifold, it has a shield/heat exchanger on it, so you may not see the crack right away. 

[gogmorgo]

30 minutes ago, eaglescout526 said:

I spaced that, it is bolted to the manifold. 
And if there’s cracks on the exhaust manifold, it has a shield/heat exchanger on it, so you may not see the crack right away. 

I don’t remember a heat shield on mine but that might be a ‘91 thing? I haven’t dug my 2.5 out from under the last couple dumps of snow yet or else I would have looked. 
 

Real advice, when you’re going for the manifold nuts, don’t be afraid to come at it from underneath. It really helps to see what you’re doing. Just don’t drop things on your face while you’re down there. 

[eaglescout526]

10 minutes ago, gogmorgo said:

91 thing

Might be Renix but I know the same manifold is used all the years including HO. But it’s got the heat exchanger for the air box. 

[mjeff87]

Check the very rear of the manifold....the front and rear connectors are studs, not bolts.  Odds are the rear one is snapped off.

 

There's *just* enough room back there to get a right angle drill involved to remove the remains of the stud if it's snapped off flush (or down in the head).

[eaglescout526]

37 minutes ago, mjeff87 said:

the front and rear connectors are studs, not bolts.

I wish this was always the case. Both my 84 XJ and 88 MJ don’t have these studs but use bolts instead. So it’s likely a year change over thing in probably 89. Course you can upgrade to the studs though.