Newbie questions on Simple 4.0 upgrades

Hey out there. Just found this site and love it. Got some basic qusetions here... first, what is an XJ exactly? I havent been able to find any model breakdowns anywhere, even on the net. I'm driving a '91 4.0L sport- is an XJ a reference to body size?
I love the truck and have been fixing up since I got it 2 years ago. I've read alot about the engine temp issues, and want to work on that. My mileage is bad and it runs really, really hot. I know they run hot, but mine is HOT. For simple mod's, what K & N filter is everyone talking about? When I go in to buy it, which is it and does it fit right in where the old one is? Also, does my Jeep have cat that may need replacing? Finally, if I put too much coolant solution in the plastic well, it soon bubbles out and overflows near the radiator until it is back down to marked level. Is this normal?
I've already replaced the water pump, muffler, radiator, o2 sensor, CPS sensor, Speedo, AIS motor, plugs, cap, wires, etc.

stuff to look at

No expert here - but here's a bunch of stuff to look at:

- is all of the air "burped" out of the coolant system
- is the fan clutch slipping
- is the thermostat working properly or is the housing gunked up
- is the aux fan (or sensor) working properly
- is the fan belt tight
- is the radiator or grill blocked

mostly common sense stuff - good luck!

'XJ' was Jeeps model code designation for the mid-size Cherokee (1984 thru 2001). They used other similar codes for other models, such as the ZJ for the Grand Cherokee (1993 thru 1998), WJ for the Grand Cherokee 1999-pres, and so on for other Jeep models.

Eagle said:

'XJ' was Jeeps model code designation for the mid-size Cherokee (1984 thru 2001). They used other similar codes for other models, such as the ZJ for the Grand Cherokee (1993 thru 1998), WJ for the Grand Cherokee 1999-pres, and so on for other Jeep models.

Click to expand...

Exactly, also YJ for 87-95 Wrangler (leaf sprung), TJ for 97-present Wrangler (coil sprung), KJ for Libertys, MJ for Comanches, then of course there's all the CJs... we won't go there

Check the Tech section from the main page for some simple engine mods. And search around on the forums here, there is an abundance of information about XJs/MJs here.

you guys for got the SJs....full size jeeps =)

shudder...

although there seems to be a stigma attached to this site as a result of some dummy's... there is a thread here that has some good basic info and FAQ's about XJ's for us XJ noobs...
http://www.jeepsunlimited.com/forums/showthread.php?s=&threadid=272033

NICE !

mengleff said:

although there seems to be a stigma attached to this site as a result of some dummy's... there is a thread here that has some good basic info and FAQ's about XJ's for us XJ noobs...
http://www.jeepsunlimited.com/forums/showthread.php?s=&threadid=272033

Click to expand...

stewed prunes - they should help you out there pal.....

But don't you have to be a Member to view the tech section? I'm a freeloader but not for long....

Depends on what you want to look at Centre. There's two tiers of the Tech Stuff, stuff just for members, and stuff for everybody (consider it a preview of our Tech Section )

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