Temp Problem

[LittleD]

Yesterday i was driving home from danbury and i decided to stop and grab something to eat, then take back roads home. Im sitting at bk and i look at my temp gauge, and it's all the way at 260, pulled into a spot, look and everything seems to be in order. Get on rt 7, start driving and the temp goes down to around ~230, does the same thing at a stop light (i had the heat cranked all the way home). Im thinking that the electric fan isn't turning on and when not moving there is no air going through the radiator.

What should i check first, if i were to hard wire it to the battery, would it be on all the time or just when the jeep is running? and what are the pros/cons to using a switch to manually turn it on/off?

[WAD357]

Seems like more then your E fan to me. If your jeep is a renix first thing to check is that stupid coolant bottle. cap or bottle could be bad and building pressure. also check your thermostat to be sure its not sticking

[LittleD]

the thing is, the temp only goes up when im not moving, other than that it is where it should be. Thermostat was done in the fall so i don't think it's that and the i replaced the coolant top because i was blowing the upper coolant hose off from pressure.

Edit: the coolant top was a pain in the ass to get off just now, but when i put it back on and turned the ac on, the fan kicked on.

[OWEN]

Not really familiar with the older cherokee's but in the ones I have worked on, the mechanical fan does the primary cooling, electric fan does the secondary. Could be a bad fan clutch. When it gets hot, shut it off and immidiately see if you can turn the fan on the clutch.

[1cleantj]

if mech fan is working you may be low on coolant, air in system, bad radiator cap or failing head gasket

[crosbike]

http://www.jeepsunlimited.com/forums...d.php?t=364431

how old is your water pump?

[LittleD]

http://www.jeepsunlimited.com/forums...d.php?t=364431

how old is your water pump?

about 2 months old

[crosbike]

did you burp the system? sounds like you may have an air pocket. how new are all the other cooling system things?

[armadasx]

But if he had an air pocket the heat shouldn't work.....or shouldn't be as hot as normal....

[crosbike]

But if he had an air pocket the heat shouldn't work.....or shouldn't be as hot as normal....

why wouldn't the heat work? and he said he had the heat cranked but i dont know if it was just on full blast or was cooking him alive or both.

[LittleD]

why wouldn't the heat work? and he said he had the heat cranked but i dont know if it was just on full blast or was cooking him alive or both.

Heat seemed to work fine, no noticeable difference.

[armadasx]

An air pocket would prevent circulation of coolant.I'm not sure where the supply and the return are for the heater core but in theory no coolant being circulated would cause the heat not to work and the motor to overheat.

[LittleD]

Bump:
Shut the jeep off today when i got to school, temp was really high, and it puked a bunch of coolant out of the bottle. Turned the key on and didn't hear the fan kick on at all, is there a fuze or relay for the fan?

[OWEN]

Bump:
Shut the jeep off today when i got to school, temp was really high, and it puked a bunch of coolant out of the bottle. Turned the key on and didn't hear the fan kick on at all, is there a fuze or relay for the fan?

Probably both, I would go through your fuse panel and see if you have any that are blown. If they are all ok, check the relay, you can check it with a ohm meter on beep and a 12 volt supply. Or just replace it. Then, if it still doesn't come on, check the 12 volt source to the coil of the relay. If there is no 12 volts at the relay coil, then the relay is not getting energized for some reason (broken wire, sending unit, etc)

Another easy way to troubleshoot your fan and system is to take a 12 volt test light and check for 12 volts at the plug for the fan. The will tell you if the fan is bad or if its not getting power... Good luck

[armadasx]

How high is really high?Could be a head gasket also.....but im sure thats the last thing you want to hear.