katiness

My mechanic just replaced the rear main bearing seal in my son's 1988 XJ. It's a 4.0 liter. He said that the timing chain is loose and that should be our next project on it. My husband usually does his own mechanical work. Is this a big job? Do you have any tips on doing it?

Abovetimberline

If he understands motors a bit it is pretty simple job,there is no real tips other than it would have been nice to do when the pan was already off,it will need to be loosened up again to install timing chain cover. if your son can be without his jeep for a couple of days just do it when he has plenty of time. I thought my was loose until i replaced it,and found out it was just fine,they have a 1/2" deflection when you push on the chain.

katiness

Yes I agree with you would have been nice to do before. The mechanic is not that worried about it when I talked to him. He says it deflects about three quarters of an inch so it is a bit loose. I don't know if that is bad or not. The jeep has 140,000 miles on it.

Abovetimberline

3/4" is more than it should be,but these chains are loose in comparison to others I have replaced,140,000 is not many miles unless it was abused,I would just run it,the worst thing that can happens is timing will slip and you will need to replace it and your son will be without wheels for a day or so.

katiness

hey thanks for the input. I know we have taken good care of it but don't know how well previous owners did. Can say for sure they didn't use good oil after doing this job There was a lot of sludge in the oil pan. At least it's been cleaned out

Abovetimberline

If you have alot of sludge it is very possible there has been some premature wear or damage that will show up sooner than later,the good thing is these engines are bullet proof and will take alot.

katiness

That is what I am hoping I have a 90. When I bought It had 132,000. It now has 230 thousand. The engine still runs good have had to replace things from normal wear for 19 year old vehicle. But I am a diehard I love my jeep I have to drive a lot in the snow and it is the best.