wconrad

Can anyone tell me what the differences are between a 1999 and a 2001 4.0 are? I'm needing a new engine for my 2001 and all I have found is a 1999 and have been told it won't work. I am also wondering what it would take to make it work?

SeriousOffroad

Before answering your question...

Why do you need a new engine? 4.0L are famous for running well with well over 200k miles on 'em.

xjbones

only thing that wont work is.....your coil pack wont have the bolt holes on the head to hold em in. but it will stay on. you could switch the heads out to take care of this.

everything else will work.

also the 99 has a distributor. make sure you note how it comes out andf when you put your coil pickup in its place, make sure it goes back in exactly the same as the old distributor came out.

i did kinda the opposite your doing but a larger year range......i have a 2001 in my 91. all bolts right in and started the first time i cranked it over!!

hope this helps.

wconrad

My current engine still runs but has many issues. I recently bought this jeep and belive it has had a ruff life. The engine is leaking oil from all over the place and when it is reved up it has a loud clanging noise that sound like its comming from the oil pan. It also has ALOT of blowby.

SeriousOffroad

For simplicity sake, any 91+ 4.0 short block with your existing cylinder head.

I'd suggest a 96+ short block though since it will have the main bearing girdle and the thicker webs.

All of the bolts-on from your motor can simply be swapped over to the new motor.

wconrad

Excellent! I figured it was going to do with the coil packs but didn't know if there would be issues with the computer. I didn't really think that they changed much on these engines through out the years but wasn't sure when it came to sensors and other electrical add ons.
I really appreciate your help! This is a great site for Jeep enthusiasts!!