99Justin4.0

Like I said I've been working solely on DOHC VW and Porsche engines since my first car when I was 16. I just turned 31, got smart, did a lot of homework and bought something reliable and relatively easy to work on and find parts for. I'm absolutely thrilled with the WJ so far. I spent about an hour lying on the creeper underneath her just admiring how well engineered everything is. It's turning out to be exactly what I wanted.

Anyway, I pulled the flexplate cover, and found nothing wrong there. Then I did a wet compression test in that 3rd cylinder and got 150psi. So that pretty much tells me it's ring/piston related. Correct me if I'm wrong. I put a third of a bottle of Seafoam down the throttle body, let it sit about 10 minutes, then ran it for about 20 minutes. It smoked way less than I thought.

I've read so many threads where people just let it go and their engines last, but the tick is kinda embarrassing and it will drive me absolutely crazy if I don't fix it.

Next step is pulling the pan. I'm sure I'll find out it's slapping. But if that's the case, does anyone know what the chances of the cylinder wall being ok enough to just throw some new pistons in? Or if it's relatively safe to run without seizing?

But again, I'm green with Jeeps, but I know some engines can live through anything. My dad's straight 6 in his 81 Econoline could run a thousand miles with no oil... It had like 600,000 miles on it, and still ran when he sold it. I'm hoping these 4.0's are similar.

99Justin4.0

I was actually thinking it was stuck up (if that even happens), not collapsed.

s346k

highly doubtful the lifter is stuck. you could run a bore scope down #3 and see what's going on. low compression isn't a terrible thing, but the noise indicates it is damaging itself when it's running. perhaps you could remove the filter and strain the oil through a paper towel or something and see if there is foreign material in it.

99Justin4.0

Well I bought an oil pan gasket. So next on the list is opening it up from the bottom so I can get a good look at what's inside. Now it's just one of those things I have to find a window of time for. I hope I don't find anything too nasty.

I saw a guy with a Dodge Dakota sounding exactly the same as my jeep at the gas station. He had the hood open so I asked him if he knew what the sound was. He said he's not a mechanic, so he's just topping off all the fluids. Well, when I was checking out of the store he yelled in through the door "check your power steering fluid! It went away!". Now that is weird. I know Jeep and Dodge share some similarities. But that would be a weird one.

One last possibility that I'm not even sure how to check is harmonic balancer. I've heard they start to fall apart and tick like mad.

But again, I'll post my findings under the pan.


Also, I just wanted to say Thanks to everyone who's offered advise. All experiences offer good advise. And even if it's not the problem, it's good to know anyway. It helps me learn faster. I know newbs on forums can be annoying. This isn't my first rodeo, I just moved from VWvortex.

99Justin4.0

Okay, started the oil pan removal/oil change process.

Just drained the oil through a 100 mesh paint strainer.

Not a spec of anything. Good sign so far.

(later edit): Oh my God it had a FRAM!! "MileGuard by Fram"... I had no idea till now.

I called the Jiffy Lube that it was last changed at and found out that it has 1612 miles on it since it was last changed. 200 of those miles were from me.

So according to all of this detective work, the lady I bought it from had the oil changed on August 5th. She then drove it 1,412 miles before selling it to me on September 15.

Now, if I knew there was something really wrong with my vehicle, I don't think I would put 1,400 miles on it before selling it. I think she was telling me the truth when she said it's just sounded like that for a long time.

Next, pan removal. I'll give the good details when they come.

99Justin4.0

Broken Piston. Cylinder wall fine. New ones Coming. Pays to look EVERYWHERE.

s346k

that's part of troubleshooting. nice work sticking with it. what is your plan of repair?

99Justin4.0

I'm gonna do all new pistons, rings and bearings. Hope to have it done within 10 days or so. Just a matter of getting the parts shipped really. I started a new thread here:

https://www.cherokeeforum.com/f5/wj-...5/#post3314121