Has anyone seen a 4.0 engine lockup without warning?
its my sons 1999 cherokee sport 4.0 auto 4x4, I wasnt there when it happened my son said he got on the hwy went about 4 miles it bogged down heard some noises (clanking?) he could not tell me what kind of noise it was making, when i got it towed to my shop it had oil and coolant, coolant looked like it might have a trace of oil in it, i tried to crank it and the starter was hitting hard but nothing turning over, so removed the serpinting belt and still locked, pulled the plugs all looked normal untill #6 came out tip is bent and porcelin missing & looked like something had rubbed on the side of the crown lightley, I was thinking it had hydostatic lock but its still frozen, help guys.
sorry for such a long post

 

Sorry, not much we can do to help...that engine's gonna hafta be rebuilt/replaced.

 

Pretty much it.

 

im more curious if anyone has seen this before without warning, didnt use oil & has never overheated

 

My wife's 01 XJ did this... Pretty messed up inside. Just junked the engine and grabbed a new one from the scrap yard... $1000 later and it ran great... My wife said it happened over the course of about 10-15 seconds so i'm guessing 10-15 minutes. I ran it that morning with no problems. Not sure what caused it but I have seen it happen before.

 

Sure the engine seized and not the transmission or something?

 

"I wasnt there when it happened my son...."

Is there a bunch of powdered rubber strewn all over the quarter panels?

 

I got a buck that says #6 piston broke. It isn't that uncommon a problem.
More often than not the skirt breaks pretty low and you get a lot of noise, but little damage, but sometimes the piston breaks closer to the pin and it's far worse.

 

yes Radi the spark plug that was damaged was on #6 cyl and the engine wont spin with a socket on the crankshaft with a breakover on it, Locked

 

thanks for everybodys imput, now its time to get a motor from?????

 

http://www.bbb.org/tulsa/accredited-...roken-arrow-ok