beach dude

ok so ive had this jeep for couple yrs now. i know and understand that the temp will rise and fall while i drive. ive seen it for a couple yrs now.
my problem is that the temp rises higher than it has ever in the past while sitting at idle and faster too. around 220-230*. as soon as i stop moving the temp starts to rise. something thats never happened before. when i start to drive it will fall again but it takes a while. something thats also never happened before. it would drop down rather fast. yeah i know 230 is "normal". but this truck has never ran that hot ever before "normally" so i would like to find out why that is. this is a newer motor with 14k on it. (jasper rebuild)

so after many hours of searching and reading ive seen a whole mess of things that it could possibly be.
things ive checked:
fan clutch; ok, did the spin test while at temp. and also saw a news paper test where you could stop the fan with 1 single sheet of paper rolled up.
fluid level; ok. no air in system. newer fluid less than 1 yr old. there should be no clogs.
e fan; runs when gets to temp (aprox 220*)
water pump; no sign of fluid leaking. sounds ok. pulley doesnt seem to be loose or wobbling. can the pump be checked w/o removing it??



things im unsure of:
temp sensor; (sending??) this is what causes the e fan to come on/off when temp goes up??
t stat; i have a infared temp gauge. (TIF7201) if aimed at the t stat housing it should read somewhere between 190-220* correct?

thanks guys. im no mechanic and far from a weekend wrench spinner also! i am trying to spend as little as possible on this. bad economy has got me trying to do a lot of my own repairs. anything that can be added to either check or consider would be appreciated!

Muaddib420

No 230 isn't normal it's high. You've got the beginnings of an overheat situation. If you're not leaking and fluid levels seem ok, something is failing in your cooling system. My guess would be bad water pump (impeller broken or not moving water well) or clogged up radiator.

Cheap DIY you can start with would be a radiator flush and see what comes out. I would buy a new water pump gasket, pull the pump and check the impeller. If its OK, reinstall with new gasket.

beach dude

sorry forgot to add. radiator is new as well.

djb383

The fan clutch "spin test" is weak/poor at best. Fan clutch performance degrades gradually with age/miles.....for that matter all cooling system components degrade with age/miles, owner neglect. If u've replaced the radiator, u've done the hard part, now replace the rest of the cooling system.

beach dude

thank you and yes im glad the hard part is out of the way. but thats what im trying to avoid here is shooting from the hip and not really knowing what is wrong. any other ways to test the fan clutch? the only thing ive seen so far is to spin it by hand or do the news paper thing. both i have done and imo it passed both of those test.

those of you who are more advanced at this may have to dumb it down just a touch and explain things just a bit more thoroughly. thanks for understanding.

mike mike

Heat issues at idle or very slow speed is a good indicator not enough air is moving thru the radiator. check condenser/ radiator for junk blocking the outside. If unsure of the condition of the fan clutch I'd replace it

EZEARL

Your XJ's gradual increase in hi temp over time is similar to mine. I kind of figured it was the fan clutch as I've dealt with the issue on other vehicles. If I shut my vehicle off when the engine temp is hi and watch the fan and it's pretty much free spinning if nothing else it's weak. I replaced mine Wed (NAPA #272310) and noticed on the front of the old fan clutch a build up of a dirty greasy material. Could be the fluid from the fan clutch. Might be a sign that it's shot.

beach dude

ok so i took the sensor out that is on the t stat housing. cleaned it off w a wire wheel and drill. took the truck for a test drive and so far so good. the temp stayed at around 210 while driving. fluctuated a little bit during stop and go driving. got home and let it idle for 20mins. it took a while but the temp did eventually kick on the e fan. i took the temp with the gauge and it read right at 210 despite what the dash gauge said. (that was slightly over 210 at the time) im going to take it for a ride on the beach later with some added strain and see if that get the temp to where it was last week (around 230* or so)

djb383

The factory fan clutch test procedure is quite drawn out and involves drillin a hole in the shroud, mounting a thermometer in the fan shroud, taking temp readings, revving the motor, blah, blah, blah. A new fan clutch costs $35 and can be installed in less time than it takes to do the factory test procedure.

Preventative maintenance is not shooting from the hip, +/-$150 in preventative maintenance (the cost of parts to replace the rest of the cooling system) is way cheaper than a $4000 motor. Preventative maintenance is what keeps u on the beach and out of the repair shop. Don't neglect the XJ cooling system, it's not the best design in the world and ALL components need to be in top notch condition. Unless your glove box is full of recent receipts indicating the cooling system components are new/just replaced, presume the previous owner did nothing regarding maintenance and now maintenance is all up to you.

Don't use the news paper to stick in the fan, use it to find a auto parts store that's running a sale on parts.

This fella's water water pump wasn't leaking.....but it wasn't working either.

beach dude

well just got back from test drive 2

driving on the street
while a/c is off, temp was normal. during stops it would rise to just over 210. e fan would come on and bring it down.
with a/c on temp rose to just over 210, maybe 215 and stayed there. stop and go didnt matter thats where it stayed.

driving on the beach
with a/c off. temp rose to just over 210, again maybe 215 and stayed there. thats just about what ive seen to be normal on the beach. you could hear the e fan come on and off and the temp barely moved.
with the a/c on. temp rose to close to 220. right about the 1st dash to the right of 210 mark.

i still feel like something is funny here. gonna loosen the serp belt and play around the the W/P pulley to see if its got play in it. its looking to me like a pump is in the near future. i'd rather narrow it down to a definite instead of buying parts just because and shoot from the hip, throwing $$ away. that is not preventative maintenance at all. its wasting $.