Recently i have got a 1995 Jeep Cherokee with a blown head gasket for cheap. As i started taking it apart to pull the head there was a nice surprise waiting for me under the valve cover. Previous owner must have left the same oil in there for ever. Jeep has about 140k miles on it and drove fine even with a blown head gasket. Never had a car before with so much sludge under the valve cover, my stealth was prestine clean compared to this with 190k miles

after poking with a screwdriver a bit

crappy cell phone pics

 

IMO no engine can take neglect and still run like the venerable old 4.0 I6!!!

 

My '98 GC Laredo 4.0 MallCrawler is coming up on 95K. Yes, I agree, 4.0 engine is bullet proof. Gotta lov it.

 

well in the end i had to get a new head, head gasket and head bolts for it. The head needed a valve job and some work done, also turned out it had a broken head bolt which caused coolant to leak out the side of the engine. already looks better going back together:

 

Dude, if the top end looks like that, think about what the bottom end looks like. After putting the money into a new head and all that work, I wouldn't fire it up quite yet. Drop the oil pan and do an inspection. The oil pump pickup has to be disgusting, and there's probably an inch of sludge in the bottom of the pan.

It's not bad to drop the pan on a 4.0, you may have disconnect the shocks and the track bar to bring the front axle down far enough to remove the pan, depending on if it's lifted and how much.

After you clean out as much as you can, put a mix of diesel fuel and cheap oil back in then run it for a bit and let it sit. Change the oil out a couple of times then put some Rotella and a quality filter and let her run for another 150,000.

Btw, I've never seen a 4.0 that could keep the oil off the ground long enough to cause that kind of build up, haha.

 

I'm with Jr on that one. Drop the oil pan and clean before you start it.

 

Yea the oil pan and rods, and bearing underneeth have got to look just the valve springs did.. Im with them on taking the oil pan off and cleaning it up.. especialy the oil pump and its little filter.

 

OH MYGO...It is very bad.....We should get lesson from this situation and be aware next time to change the oil regularly..It become very dangerous problem for car

 

That is just plain awful!

My wife and I had a 1993 Wrangler 4.0L, traded it for our 2003 Wrangler, that had 117,00 trouble free miles (engine, transmission, etc.). Such a great vehicle.

My parents have a 1987 Cherokee 4.0L (240,000 miles) and a 1989 Cherokee (175,000 miles) that are still going strong. They still have plenty of power and run smoothly. They also have a 1996 Grand Cherokee 4.0L that has around 140,000 miles.

It is too bad that it was not cost effective for Chrysler to update the 4.0L, to pass the new emission/safety standards, to have kept it available in the 2007 to present Wrangler. Great motor!

 

Man is that bad. Those 4.0 are pretty much bullit proof. My 04 Grand has the 4.0 in it. I use Mobil 1 with a Wix filter.