skoobydoo

OK, sit back & listen to me whine...lol

It was a rainy Florida day back in....OK, I'll be serious now

2000 Jeep Grand Cherokee Laredo 4.7 4WD (Engine Code "N")
165000 miles
See Pics of damage >>>( https://www.cherokeeforum.com/member...cylinder-head/ )

Jeep overheated while driving in a bad thunderstorm. It shut it self down when it got too hot. (That was the first time I even knew there was an issue) Had it towed home. Looked it over and easily saw that the water pump had cracked badly. Replaced water pump.

Went to start it up...Starter was bad (Under warranty, replaced it)
Started right up, but loud knocking under left valve cover. Took it off and a mixture of antifreeze & oil pooled everywhere. (No White Sludge ANYWHERE)
I pulled the head to obviously replace the Head Gasket.
To my surprise, the #1 piston was demolished, like it was disintegrating by itself. Luckily just a small scratch in cylinder wall. Honed it out, replaced the piston & rod bearing. Sealed it up and it started right up.

Seemed to run smooth, but now a lifter/lash adjuster sounded really bad, and there was white smoke in the exhaust & white smoke coming out of the oil dipstick (blow-by). (We all know what that means) So i pulled the Passenger Side valve cover off & same thing...Anti Freeze & oil mixture pooled everywhere. OK, pulled the head off & the 2 front pistons are torn up (again minor scratches in cylinders)

Now, was it the overheating that caused the initial breakdown, or something else that caused the pistons to break apart and in-turn cause the overheating, or was it a full moon, or?....you get where i am going with this...lol

What else should I check? Should I now tear down the Driver Side again to see if any of the loose metal chips that are in the intake-manifold have made their way back into the DS head? I LOVE MY JEEP, BUT!

JimBC

Sounds like the overheating caused the head gaskets to leak antifreeze into cylinders which in turn increased combustion pressures enough to destroy pistons. Keep eye em, to make sure was just gaskets and not warpped head(s).

JimBC

BTW, I too love my jeeps. But i figure i have about 500-600 bucks to go before my 2000 grand is at an acceptable level of reliability. Replacing my crap front driveshaft this weekend (hopefully), with a u-joint style shaft from a 2004. just finished replaceing front brakes and brakes to the newer styles that r on the 2003-2004 models. next will be the rear axle then should be done.