blackvmax07

hey guys im new to this whole jeep thing but 2 weeks ago i bought a 94 cherokee 4x4, 4.0l with 195k on the dash. The jeep was owned by an older man that has had it parked for the last 6 years, after changing a battery and addin some gas it got me home. So far iv changed the plugs, few gaskets, rear axel and fuel filter. My question is when i drive it for about 5 minutes it jumps up to about 230degrees, and after research i can tell its a common thing but i cant see any leaks and the radiator fluid looks brand new. Wat could this be? and the second thing is when i turn on the ac i get a loud screachin noice for about 8 seconds. Wat could that be? thanks for the help guys

tjwalker

Does it go to 230 at IDLE, on the HIGHWAY or both? The devil is in the details with overheating symptoms.

First thing is to verify belt tension. A marginally adjusted belt can affect both water pump operation and can give you the squeal you describe. Inspect belt. If it is glazed, excessively cracked or has more than 60k on it, replace it. I like the Goodyear Gatorback as a 4.0 replacement belt.

If it is still running hot, start with the basics. New 195 degree thermostat, new radiator cap, and see where you are at after that. Verify the operation of both the fan clutch and the electronic fan (which should come on when the temp reaches about 217 F)

blackvmax07

when it just idles its fine its just when i get goin that it heats up, but im sure this belt has never been changed so ima do that. The reason i bought this jeep is to pull my mowing trailor thats why i dont want it runnin hot cause its gonna be used in the heat of the summer. Would it be a good idea to run a 160degree thermostat? Thanks for the help though ima do the belt asap

fishtaconc

Stick with the 195 Tstat, get a infared temp gun, the laser point and shoot type, this wouldnt be the first XJ to have a bad temp gauge sender.
To test the mechanical fan, while the engine is cold open the hood (with engine off) and spin the fan, it should spin fairly freely, start the jeep, let it get to normal op temp, shut it down, now spin the fan it should be tight if not replace the fan clutch. You said the coolant looked new could be an air bubble.

tjwalker

Stay with 195 for the stat. Just putting in a lower spec'd stat doesn't mean that the engine will run cooler. Just means that the lower number stat opens sooner.

Get a new belt on there for starters as it needs it. But if you have trouble with engine overheating only at load (highway), then you most likely have marginal flow which means the water pump, radiator, or combination.

blackvmax07

ok thanks guys ima try this stuff out and post up the results