I have 1996 XJ with a re-manufactured motor with under 23,000 miles. The thing has been a POS... NEVER buy a Jasper engine. Anyways, I had to have cylinder 2 replaced as it was misfiring. Cylinder 2 tested at 50 psi and was causing a massive leak. According to my mechanic, the cylinder looked to have a manufacturing issue based on it's seals..? (I'm not mechanically inclined). I had my mechanic replace the cylinder and threw up a little when paying for it (warranty had lapsed by 1 month).
30 miles later and it's misfiring again with codes p0300 and p0302. It's also idling super rough, surging, and blowing a little white smoke when first started in the am. I brought it back to the mechanic and he is saying that cylinder 2 has a small crack that is leaking coolant (part defect). He said he used a little camera to find the leak and is making calls into the parts store...
My point is, does this sound correct? Could a small crack in cylinder 2 causing a coolant leak cause random misfiring (p0300) and super rough surging idle. If they replace cylinder 2 again (and it's a properly working part) will my XJ go back to running properly?
This is all becoming a super stressful issue for me. I am terrified of engine issues.

Thanks all

 

I don't understand the warranty issue. You over 3yrs? I've got a Jasper in my Blazer with a 3yr/100k warranty.

 

Yes, the three year warranty had expired by 1 month. It hadn't been installed and running in the XJ for 3 years, but they count from time of purchase, not install. They only offered to sell me another engine at 60% the cost and no labor covered.

 

"the cylinder looked to have a manufacturing issue based on it's seals..?"

This is quite vague and sounds mostly like bable. A piston can be replaced but not a cylinder. For that you need a new engine. A crack would certainly cause the problems you're having and likely the problem all along. Did you have an overheating problem before this?

 

Been wanting to inquire a bit more but he admits he's not mechanically inclined. Like did his mechanic sleeve the cylinder?

OP,were there any problems during the 23K miles? Jasper engines in order to be warranted have to be installed and serviced by registered dealers. When my dealer/friend fired mine up there was an almost imperceptible knock he said. Jasper had him check a few things then shipped out a fresh motor. No cost to my friend or myself.

 

Yes, I was having some overheating.

 

There were no issues up until a few months ago when it started idling rough. I figured it was a dirty throttle body or sensor issue. But it continued to get worse until the CEL came on with the misfire codes.
I did have the engine installed by a registered dealer. But by the time I was told it was a cylinder issue my warranty had lapsed by 1 month and Jasper claimed that they were being "very generous" with the offer of 40% off a new engine.
I don't know if this contributed to the problem delay, but I rarely drove it up until a few months ago when I started taking it back out into the desert for longer hauls.

 

The overheating issue is not good and is very likely the basis of your problem. During the warranty time did anyone notice a loss of coolant? What I'm getting at is unless there was a total failure of something in the cooling system that caused a extreme overheating situation there should have been hints that something wasn't right. Takes a lot of heat to crack a block.

 

So I probably have a cooling system issue that caused the problem? I never noticed or was told about any leaking coolant, but heavily rely on my mechanic as I lack most of the needed mechanical skills. The only times I noticed it running a bit hot was when I was out in the desert and figured it was due to the outside temp and running distance.
When I get home, I'm going to look over the mechanics receipt and write-up for more specific information regarding the repair.

 

If you throw cold water into an engine that has boiled over, that'll doer.

 

That sounds very generous man haha.

 

That's for sure!!

 

Is it possible to sleeve a cylinder in place? I always thought that could only be done in a machine shop during a full rebuild.

 

Ok... so I looked at the receipt. The mechanic replaced the #2 cylinder head and head gasket. I'm going to assume that the current crack he is referring to is in the new head.

Would a crack in the cylinder head or gasket which is leaking coolant cause really bad surging when at idle? I just want to make sure everything is being fixed before it turns into an even bigger issue.

Should I also have the cooling system inspected?

 

I'm speaking here about mechanics in general. When it comes to the substantial layout of money required when having to pay to have something major done to your vehicle in order to have the replacement component warrantied it best be done right. When my Jasper was installed a completely new (except for the heater core) cooling system was also installed. What ever my friend felt could be detrimental to the engine was replaced. Since then I've paid for nothing except oil and filter changes. Two CTS sensors have failed,one oil pressure sensor,and one radiator hose clamp. This over a period of a little over 2yrs. It was done the way I would have done it had I been doing the work. If one is not capable of doing it choose who does carefully.