I've only skimmed the thread quickly. If you can drive at speed without issues but sitting idle causes it to overheat, your fan is have some sort of issue. It could be hitting the fan shroud (unlikely) or the fan clutch could be bad.
Overheated but not showing it
- Thread starter KingCarGuyZ
- Start date
I've only skimmed the thread quickly. If you can drive at speed without issues but sitting idle causes it to overheat, your fan is have some sort of issue. It could be hitting the fan shroud (unlikely) or the fan clutch could be bad.
Jakejeep2005
Member
OP
Replaced the fan clutch with a Hayden unit when I did the pump (read that they engage as hard and as early if not earlier then MOPAR, certainly hear the fan more than ever before.) No evidence of self clearanceing on the fan shroud. Maybe a new fan? Though the old one seemed ok, maybe a few dings here and there.
Jakejeep2005
Member
the fan only gets the hot air out of the engine area. i don’t think that’s your problem. what kind of coolant did you have put in it. was it pre mixed with water?
There shouldn't be a need to improve upon the Mopar cooling system with any aftermarket parts. The stock mopar parts are more than capable of any scenario a TJ will see. I'd get a scanner on the Jeep while driving you can better diagnose what causes it to overheat. The gauge is useless (as you know). If it takes an hour and a half to overheat, it sounds like something is intermittently not working versus something just being broken within the system. The most likely in my head would be the thermostat sticking.
OP
Shop put in a premixed HOAT (Orange) watched them do it when they did the coolant flush (didint want to spill more coolant on my driveway than I had to) plus I had distilled water And some Preston (drive flush) in the Jeep for about 2 days between doing the pump and getting her flushed. IDK what brand of coolant was used though.
John Scoggins
TJ Enthusiast
The fan draws air across the heat exchanger(s) when idling and at slow speeds, it is not really needed at other speeds that is why there is a fan clutch. It is not there to blow the hot air out of the engine compartment, if anything it adds the heat from the heat exchanger(s) to the engine compartment.
OP, Sounds like you need a new radiator, assuming that you have burped the air out of the system. Does it blow hot air when the heater is turned on when it is over heating? If it does not them you might have some trapped air and/or a plugged up heater core.
If it blows hot air and you have bleed the system of air it seems that your radiator has some plugged, or partially plugged passages and/or you have some gunk moving around in the system.
OP
just had it flushed so one would hope there is no gunk moving around in the system, but it is a possibility.
Ambient temperature to hot to check on the heater.
my theory (and I’ll be it not a good one) is that the fan Is sucking a bunch of air into the engine compartment. That air then had no escape to the back of the so gets blown out to the front under the bumper (evidence by how much hot air you can feel standing in front of the Jeep) so the fan then sucks in that air again (it’s in front of the Jeep) and this cycle continues until you have superheated air trying to cool the radiator which I can only assume is less effective than fresh air.
I will admit that while this theory is plausible, a stuck thermostat or dud rad. Is far more likely.
the system is burped and free of Any air pockets That I can find.
OP
Before we get all hastey, I may have found the problem,
is it just me or is my fan on backwards?
correct me if I’m wrong.
Engine spins clockwise (As seen standing at the front of the Jeep facing it) And therefore so does the water pump, that fan is set up where a clockwise rotation Would be pulling air from near the block and pushing it out the front. Which I’m guessing isint correct?
someone feel like walking out and taking a picture?
Even though the engine spins clockwise, the routing of the serpentine belt spins the water pump counter clockwise.
OP
Ahhh, cause gears. Got it. Welp there goes that theory. Guess I either need a new rad. Or a new thermostat. Yay
OP
I'm not convinced the flush was done properly. Block has to be clean for the coolant to work. There is no problem with plastic impellers on water pumps. The radiator also has to be clean to work right.
OP
Solid possibility, I did drive around with the Preston flush and distilled water for a few days before I took it to get flushed. They did hook up a pressure flusher and it looks clean. But that is still a solid possibility.
Only way I know to tell is to pull the thermostat housing and look in there.
OP
So I have been a bit busy working on other cars to get to the thermostat yet, but I have more info. I got a wireless code reader and a data logging app, so now I can give accurate responses and not just what I “think happened” so here is how it goes
took the Jeep on about a 40 min drive (20 stop another 20) she’s running 205-210 hwy and 210-215ish city. Neither of these number do I find terribly concerning however, after stopping and idleing for less than 5 min she climbed to 235. This I do find troublesome.
after the drive I tried to spin the fan clutch, it doesn’t spin freely, but it’s not to difficult to spin by hand, if I give it a solid push it will make it about .5-.75 of a rotation. Does this seem normal, low?
Also in the return trip the blower fan for the A/C kept cutting out.I’m guessing some sort of over temp protection.
I am now sceptical of my fan clutch, thermostat, rad, and somewhat of my coolant temp sensor (the one in the water jacket) as it’s an orileys unit and I’m wondering if it’s what’s telling the PCM the temp and needs to be replaced with MOPAR.
thoughts? Also if I can figure out how to upload the CSV files from my trip I’ll do so.
took the Jeep on about a 40 min drive (20 stop another 20) she’s running 205-210 hwy and 210-215ish city. Neither of these number do I find terribly concerning however, after stopping and idleing for less than 5 min she climbed to 235. This I do find troublesome.
after the drive I tried to spin the fan clutch, it doesn’t spin freely, but it’s not to difficult to spin by hand, if I give it a solid push it will make it about .5-.75 of a rotation. Does this seem normal, low?
Also in the return trip the blower fan for the A/C kept cutting out.I’m guessing some sort of over temp protection.
I am now sceptical of my fan clutch, thermostat, rad, and somewhat of my coolant temp sensor (the one in the water jacket) as it’s an orileys unit and I’m wondering if it’s what’s telling the PCM the temp and needs to be replaced with MOPAR.
thoughts? Also if I can figure out how to upload the CSV files from my trip I’ll do so.
Cold or when it should be easy to spin mine will rotate at the end of a blade less than 6" from where I stop pushing. 1/2-3/4 turn hot I'd say it's toast.