Let me start off by introducing myself. My name is Matt, im from Minnesota, and recently purchased a 2001 Jeep Cherokee Sport aka an XJ. I must say it was love at first sight with this Jeep, found a guy who had a Solar yellow XJ with only 86k on it. Needless to say i snatched it up pretty quick. A day later i was driving and noticed my "check engine" light had come on. Low and behold i believe i am yet another victim of the "heat soak" issue as it only happens when i drive on the highway, park it, and come back soon and try and start it up again.

I did some searching on here and now have a better understanding of whats going on, and hopefully some fixes for it. Hopefully these XJ's can live up to their name, i was a HUGE fan of these and heard nothing but good things about them, go figures i finally find one i cant live with out and it may be a lemon. Anyways enough ranting.

Hope everything turns out okay. Yellow seems to be a pretty rare color, lets see some pics!

drain and flush the coolant, add a lower t-stat and work from there.

if it no the closed cooling sysem. change your radiator cap. if its bad and biulding up to much pessure the jeep will run hotter.

i appreciate the input guys, i'll definitely give them a try.
The check engine light went off and i haven't had any issues of it since *knock on wood*.

x2 the fuel in the fuel rails turns to vapor from the heat causing the hard starting misfires.

Hey Matt. Welcome to CF.

Welcome from Wisconsin. I keep reading about people with overheating problems. People putting in vents, or raising the hood corners. My XJ came with the winter insulation pkg. And I've never had a problem.

If you keep your cooling system in good shape it should cool fine. These are prone to problems, but many thousands of people are able to keep their jeeps cool just fine

Before you put in a cooler t-stat try the flush and fill as well as any other trouble shooting fist. swapping t-stats is a old wheeler trick to keep it cool, but the designers of the 4.0 intended the jeep to run at a specific temp. If you make it too low it wont be good for the jeep

Chuck

Welcome aboard. Moved over here to tech since it is really a tech post.

I believe this is the TB related to your heatsoak issue. The heatsoak issue relates to the #3 injector and vapor, and has nothing to do with the coolant, t-stat and such cooling system parts.

1803103 - 4.0L ROUGH ENGINE IDLE AFTER RESTART FOLLOWING A HOT SOAK
Date: 09/05/03 (supercedes 1802702 dated 09/06/02)
Model Year(s): 1999-2004

Description: NOTE: This bulletin applies to vehicles equipped with a 4.0L engine. This bulletin involves the installation of a fuel injector insulator sleeve.

Details: Customers may describe a 20 to 30 second rough idle following the restart of a heat soaked engine. This condition may be most noticeable when the engine is restarted following a prior 10 to 20 minute heat soak in hot ambient conditions of approximately 32 C (90ºF) or higher. This condition may be consistent with short city stop-and-go driving trips and can be aggravated by the use of fuel with a high ethanol content. Depending upon various conditions a MIL may occur due to DTC P0303 - Cylinder #3 Misfire.

This condition may be caused by heat from the exhaust manifold that following engine shut down migrates to the area around injector #3 and causes fuel vapor to form within the injector. This in turn may cause a momentary misfire of cylinder #3 until the fuel vapor is cleared of injector #3. The insulator sleeve lowers the injector #3 temperature to a point below which the fuel will not normally vaporize.

If vehicle exhibits a rough idle, and if a misfire of cylinder #3 is observed following a 10 to 20 minute hot soak, perform the Repair Procedure.

Parts required:
56028371AA Ignition Wire Shield

Repair procedure:
1. Cut insulator sleeve, p/n 56028371AA, to make two (2) insulator sleeves about 25-30 mm (1 in.) in length. See diagram.
2. Install one sleeve around injector #3, with the slit on the upward facing side of the injector. Install the other sleeve with the slit on the downward facing side of the injector.
3. Confirm sleeve is flush to intake manifold surface around injector.
4. Check injector #3 wire and ensure that the injector is rotated to a 2 o'clock position (from driver?s side of vehicle).

forgive me for highjacking but where is this info from? it seems very professional.

Do a google search for Jeep Cherokee TSB for your year model and you will find links to various sites like alldata and automd...TSB are published by the auto manufacturers. They are not recalls just since to be classified as a recall it must be a safety issue and so on.

I have 2001 with the same problem. I cured it by flushing the cooling system. New Thermostat. 2 bottles of Redline water treatment. New radiator hoses. Reflective insulation wrapped around fuel injectors. Reflective heat shield material sandwiched between intake and exhaust manifolds. No problem now.

Did you try doing the insulation first?

From the TSB it sounds like you didn't need to do anything but the insulation...