MooreALX

I'm new to Jeeps, I bought my first one about three weeks ago, a 2000 with the 4.0. The dealer said that he had put new head gaskets on it. We just hit a warm spell, and we went from single digit temperatures up to 50s and 60s, and my engine overheated twice. I took the the thermostat out last night, and the engine didn't have a drop of coolant in it. The resivor has had plenty of coolant in it, and the level hasn't changed at all. I took the water pump off, and and it look practically brand new. I also drained my oil; there isn't any foam, but I can tell that there is a bunch of coolant in it.

Thoughts? As of now, I'm planning on pulling my head tonight. Anything I should watch out for since I haven't done much work on Cherokees before?

Rmart30

2000 and 2001 have a head (0331) known for cracking in the oil galley between # 3 and 4 valve springs directly under oil filler hole. Some will go on for years and thousands of miles with no problems, but usually after they have been run hot it will eventually crack.

Results will be coolant disappearing and going into the crankcase and if let go on long enough will wipe out the bearing resulting in low oil pressure.

You should get the newer version of the head if your going to pull yours..... it will have TUPY cast into it. The older flawed ones will not have TUPY on them.
You can get a new one from Alabama cylinder head or Clearwater cylinder head or find a used one off a 2002 or newer and have it reworked.
If it doesnt have TUPY cast into it, it is not the upgraded casting.

MooreALX

Thanks! I spent a while on the forums last night, and read about the bad heads in the 00-01. I hadn't seen anything about the TUPY. How can I tell if a head that I get has the TUPY cast into it. Even at the places you recommended, I didn't see anything about it there. Right now, I'm looking at getting the one from AutoZone. After reading your post, I looked up a head from a 2002 4.0, and it sent me to the exact same ones. So are these heads the good ones?

Here's the one I'm looking at:
http://www.autozone.com/autozone/par...2806_159451_0_

Thanks so much!

---Alex

tjwalker

Yes, the 0331 head is subject to cracking. Casting defect between cylinders 3-4. Pulling the valve cover and performing a search with a good light can usually tell the story.

I'd start there.

The 2003 and newer Jeep 0331 heads are fine and were sourced from the Brazilian foundry TUPY. They have the marking TUPY between cylinders 3-4.

Another good option is a fresh head from Clearwater Cylinder Head or Alabama Cylinder Head. Both are very reputable vendors that have helped out hundreds of 0331 owners.

Around $400-$500 shipped to your door. Warranties vary a bit. When you search their website, click on CHRYSLER heads, not Jeep.

Good luck

MooreALX

Just thought I give a conclusion on what happened.

Talked to the dealer I bought it from, since I had only owned it for 3 weeks. He agreed to pay labor, if I payed for parts (at the shop he goes to). I really wanted to do it myself, but that's not really an option with as busy as I am during the school year. Anyways, the guy found that my head was cracked, and we replaced it from a used one that we had reconditioned. After replacing it, he said the radiator started spaying everywhere, and concluded that was the original problem. He replaced it, but I'm still skeptical as I haven't smelled any burning coolant or seen any dripping of any kind. But we'll see I guess...

Thanks for all your help!

By the way, what spark plugs run best in the 4.0?

tjwalker

84-99: Champion Copper plugs
00-01: NGK The NGK seems to be a better match for the coil pack ignition

Ensure gap is at .035