Still overheating, but at idle only

Ive changed the thermostat and bled the coolant system. The car does fine when Im driving it, but its when Im at idle that it'll start to overheat.

The temp climbs and my secondary fan doesnt come on no matter how hot it gets. If im at a stop and its hot and I put the car in neutral and give it a bit of gas and raise the rpms to 1500 or so, it begins to cool down a bit.

Coolant is flowing through both upper and lower hoses, not seeing any seeping from the WP either. Any other ideas?

time to find out why the fan isnt working......maybe turn the a/c to see if it turns on then. if not, i would just hard wire it

hard wire it to what?

ninobrn99 said:

hard wire it to what?

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to a switch, or so that its always on when the ignition is on

well, it does come on with the a/c.

I take it your a/c doesn't work, right? I unpluged my a/c compressor to run the fan with the switch.. When i notice it is getting hot i flip the dash switch to max a/c.. poof, fan runs till i turn off.. HTH

the a/c does work. I just dont use it much.

so turn it on when she starts to get hot, while at a light.. this will keep it cool..When you get a chance, buy the sensor from a parts store.. i would test both relay and sensor first

i can do that for now, but I dont wanna band-aid it. I would like to fix the problem.

Sorry i posted before i finished.. My bad

don't band-aid the problem by hard-wiring...

my $$ is on a bad mechanical fan clutch.. with the engine off turn the fan by hand. the viscous clutch should let the fan turn but not spin freely.. if the clutch is bad the fan will spin with the engine but not fast enough to move air thru the radiator. revving the engine moves the fan faster and draws air thru and driving creates air flow..

The temp climbs and my secondary fan doesnt come on no matter how hot it gets.... I take it you didn't read the tread..

scottmcneal said:

The temp climbs and my secondary fan doesnt come on no matter how hot it gets.... I take it you didn't read the tread..

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i did.. mechanical fan should still keep it from climbing too high.

Ive spun the clutch. it doesn't spin a full rotation, but it is a bit easy to spin.

Mine is new, it still need the secondary when i idle alot.. But then again it is 98 right now.. 9:50 pm

Well I just replaced the fan clutch and its still overheating. Guess that's ruled out now.

How long has it been since you replaced the water pump? The impeller could be missing material from corrosion. Also have you ever put any of that radiator leak fix in it? It could have a low flow through the cores or elsewhere.

Not sure when the WP was last replaced. I havent ran anything through the radiator either. Ive been looking for leaks but dont see anything to be concerned about.

well lets try a experiment. Get your engine up to normal temp and shut it down. run a battery + and ground wire to the fan connector and use a bit of tape to temporarily hold the wires into the fan connector socket. ensure it is spinning the right way if not then reverse your connections. now get in and let it idle away while you watch the gauge. If you do not see it warming up to where you do when you sit at a light then I would assume the water pump fans and thermostat are all good and that you do not have trapped air in the system. Disconnect your temporary wires and put every thing back to normal.

Now step two is to find the aux fan relay in the relay box and just swap it out with another one from the box, I usually use the fuel pump relay since it is obvious if the relay is not working the jeep wont start. Now assuming the relay works in the new location and the jeep started you can count out that as the problem.

Next is the temperature sensor for the fan just buy one and replace it, I have found testing it can show it's condition but rarely is the test done with the engine in all temp ranges so the test is basically useless. If you do not know where this sensor is look it up in a haynes/chilton manual or fsm.

I deal with these types of issues all the time here in California. I also suggest as a preventive measure if you do not know when the last coolant flush was done do one and if you have not cleaned the radiator fins do so with some simple degreaser and a gentle stream of water from the engine side out.

scottmcneal said:

I take it your a/c doesn't work, right? I unpluged my a/c compressor to run the fan with the switch.. When i notice it is getting hot i flip the dash switch to max a/c.. poof, fan runs till i turn off.. HTH

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Hallo. I unplugged the A/C too and depressuride it also. Is that the reason why the elec. aux fan is not working anymore? Without pressure in the A/C it won't work imo.
If that is the reason I will fix it with a relay and a dashswitch. Bye