Big D Squared

My 1994 Cherokee is over heating I just changed the water pump and after I changed it it hits 230 degrees to 250 when I sit at idle for 10 min or less could it be the thermostat? Plz help

nickxj94

possible i would chenge it out just to be safe there less than 10 bucks and get the 190 t stat... also is your aux fan kicking on it should when the temp hits 220 if not may look for a blown fuse and or power to the fan. the fus should be on pass side under hood,,mine is

stev-o

Could be your thermo but id be careful thats way to hot for an xj

jakbob

what you can do;

burp the air out of the system
check the mechanical fan clutch (with motor idling, take a rolled up newspaper and try to slow the fan down. if you can, the clutch is bad)
bad temp sender (for the gauge)

what were the symptoms before the water pump was changed? did you take off the rad cap and fill from there? what are your coolant levels like? need a lot more info....

jakbob

my bet is air in the system, and the fan clutch is toast. if there wasnt, the e fan would come on. either way, your aux fan shouldnt come on in idle with the AC off.

stev-o

So some reason my e fan is always on the previous owner must of hot wired it to always stay on or something

Big D Squared

How does the fan clutch go bad ......also the water pump was leaking and the pulley was shot and the belt was coming off and the fan ate it up and wrapped around the fan and the side fan turns on when the temp hits 220

Solomon7

Your fan clutch is bad. It just is.
Doesn't get warm moving does it?
Fan clutch.
YOu could go with replacing it with a stock one, or use a 94 ZJ's HD one.
A ton better at cooling, albeit with a little more whir since it locks up sooner and stronger, pulling more air.

If you go HD ONLY get Napa part# 272310. Do NOT get the "MaxKool" version as it won't fit.
Only get part 272310 and only from Napa. Others won't work.

If you wheel then go HD unless you plan on upgrading to all electric fans.

Either way, replace your fan clutch.
It's super easy. Just use a piece of cardboard against the radiator fins to spare your hands and avoid damaging the rad when r and r'ing the clutch. the HD clutch will be a tighter fit but IT WILL FIT, and you'll love it. XJ's cooling systems are barely keeping up when new at best and they need all the help they can get, especially as years go by.

Stock fan clutches go bad after 5 or 6 years at best and once the other components get older it's more and more importand the clutch locks up or you're hardly pulling air at a stop or low speeds.
I did the HD a few years ago and never get over 200 no matter what.

Do a "long flush" of your cooling system too. Rad, and Heater Core.
Keep your 195 thermostat. Doesn't matter what thermo you use, the engine will eventually reach the same temp regardless of flow.

jakbob

it works similar to a torque converter, except when the fluid inside heats up, more of the rotation from the pulley is transfered to the fan, making it spin faster.

jakbob

on as soon as you turn the key? the aux fan is a great bandaid to cover up underlying issues. like the mechanical fan clutch.

stev-o

YA comes on wen u turn the key

Big D Squared

Fan clutch worked put it in this morning and running like a champ

jakbob

Is your ac or defrosters on when you start? If not, sounds like a PO hardwired it.

Thanks for posting that so people in the future when searching can see.

VhoffXJ

Have same problem, then it wont start if you shut it off. My fan eletric fan kicks on at 250 though, its 2001.

stev-o

Man u better be careful gettin up to 250 is pushin wen that head is know for cracking at high heat