Hey guys,

Recently bought a 99 xj with a 2.5 that has some head issues (leaking coolant into the motor somehwere) I've dealt with similar problems on different vehicles and know how much of a PITA it is to deal with. I found some 99 4.0s that would financially be a better deal than fixing my 2.5, so...

I was wondering if anyone has any insight on swapping a 4.0 into the 2.5 xjs, ie is it equally a pain? Are the 4.0s compatible with the 2.5 engine mounts, trans, etc?

I'm just on an information hunt right now as I haven't found too much so far, so any and all info is greatly appreciated!

 

The motor and trans is sort of "married" to the puter'. The puter is sort of "married" to the rest of the Jeep. Idk about physically fitting a 4.0 where a 2.5 was, but that would just be a beginning.

Long ago my 84 W/2.5, head cracked. Found another head, lapped the valves and installed. All good! Didn't cost much more than the gasket set. Still drives fine right now, but has been non-oped 10 years since I got a jeep with a 4.0.

 

You need new PCM of same year jeep with 4.0, new bellhousing for transmission, motor mounts, harnesses, etc

 

Hopefully crusier54 or ccken will answer your question as I'm sure they will know all the details of the swap other than the ones listed above.

 

It's a lot of work. Bell housing pattern is different. So, a different trans.

Not for the faint of heart.

 

Short and sweet and to the point, thanks for the input.I'm thinking repairing my 2.5 is what I will stick to. Thanks guys!