If so when do they both need to be replaced ? I have 138k miles and just talked to previous owner(owned it from 44k to 129k when I bought it) and he said he didn't change it....

 

......sigh.

Timing chain. Not to be captain derk of the U.S.S Anus, but the search button does wonders when used. As far as replacement, I forget the exact interval... if one exists. Usually they last until they start slapping and making noise... that's when they're replaced.

 

A local mechanic said it was belt and wanted to change it out

 

It's a chain.

Find a new mechanic.

 

Alright thanks guys, I was at the mechanics when I posted this... Now I won't be there anymore

 

Good choice.

Not every one will know it all, but the Jeep 4.0 has been around long enough that any decent mechanic should know about it.

 

I have 250K HARD miles on my 92 4.0. It could probably use a new chainset. But, I am cheap bastard right now. Will have to wait till summer.

If it fails it's no biggie. The 4.0L is NOT an interference engine.

Seconding the "Get a new mechanic"....

 

I changed mine at 140k....a bit of a slack but no change in performance.
Fairly easy but i wont do it.

 

Seams odd they said it needed a T/belt.... sure he wasn't talking about a serpentine belt? just curious. That is embarrassing for them if they really thought it had a T/belt...

 

 

I thought the timing chain lasted the life of the engine unless it made excess noise ? The timing chain was one of the reasons for my dad choosing a 2008 Infiniti G35 over all of it's competitors(not the main reason mind you), they said timing chain lasts life of engine. He has 149k miles on it now, I only have 138k miles. Why are you guys changing out timing chains at 140k ?!

 

I wasn't very smart.....that's why .
I'm just sharing my experience.

 

Yes most are listed as "for the life of the vehicle under normal wear" then "normal wear" is listed as moderate temperature and load for the life of the vehicle, which doesn't really exist lol

But in most cases a T/chain will last for the life of the engine, I would not worry about it unless it makes noise or your in there already...

I hve seen chains stretch and break, but its not common.

 

And, as stated earlier, we do not have an interference motor, so you wouldn't destroy the motor. Just everything around the timing chain.