seven

Hi, I was wondering if anybody has run across this situation.. My brother picked up a 2001 cherokee sport with the 4.0 auto nice truck,. He already purchased it and I was going to meet him to tow it home. When I arrived their I opened the hood and saw the previous owner had done the head.. He claims he put a new head but I can see the 0331 casting on it and it is painted a high gloss almost powder coated red finish on it . He the po swears it is new or paid his mechanic to install a new head.. My question is has anybody ever run across this type of head and does anybody have any ideas on it (the red paint)?? I can see the head was def. replaced and it runs within the temp range but has a miss and is giving a cel code of p1391 camshaft sensor which I have replaced with a mopar product and as soon as it warms up the code returns?? The truck has high mileage and I can see that the po must have overheated it pretty good as the brown stains are all over the engine compartment..I guess my next step would be to do a compression check and see what kind of readings I get.. The head actually looks like it was professionally painted just wondering if anybody else has run across this.. Oh truck was purchased in the Bronx, N.Y. Thanks for your advice.. Bill

tjwalker

I can't help you with the origin of that head, but the P1391 is intermittent loss of either the cam OR crank sensor signal. So the crankshaft position sensor is still a possibility here for that code and symptom.

As for the replacing of that head, it was almost assuredly done because the original head cracked, not uncommon for the factory 0331 head on any of the 00-01 XJs. The signs of an overheat are probably what cracked the head.

Depending on how long that head was cracked, there could be some internal engine damage to bearings, etc. A compression test for a new-to-you vehicle is never a bad idea, but isn't always conclusive of some engine damage.

How is the oil pressure? Cracked head results in coolant mixing with oil which will result in lower oil pressure if it wasn't resolved quickly. Spec pressure for the 4.0 is as follows:

*Not less than 13 psi at HOT idle
*Between 37-75 psi OVER 1600 rpms

seven

Thanks for the reply, yes I am pretty sure it was replaced I am guessing the po painted it red why I don`t know and I have not been able to reach him?/ I have dealt with these before actually two of them I am a backyard /hobbist and both of them were my nephews trucks.. I installed a new head on one and the other I had the head rebuilt both are still running strong but at first sign of trouble I was able to diagnose it as a bad head and had it machined and I reinstalled it with new gaskets and bolts No damage to the berings. This engine has over 200,000 miles and you can see the brown overheat stains all over the engine compartment, when you first start it you can hear a faint knock and oil pressure is about 60 and drops to 35 -40 lbs when warmed up and missing becomes more noticeable It appears to be clean with no anti freeze mixed in that I can see.. My plan is I have a 1998 4.0 that runs great with about 80,000 miles .. If I can reuse the head that is on the 2001 coil pack motor I would like to put that on the 1998 block swap the dist out for the cam shaft sensor and install in truck using the 01 intake and manifold I am pretty sure the oil pressure sending unit from the 01 will have to be swapped over also. I am not sure about the head from the po?? I just read it could be a good reman. head from a 2002 gc and would have the 0331 id number but you have to remove the oil cap and look for the tupy stamp on head..