goblinish15

So i drive around and my temp guage is always at 210. Then when i pull inot a driveway it starts going up. It get to about 240-250 when it idles for about 3 minutes. My seconday fan sensor is bad and doesnt turn on when it gets over heated. My radiator hoses have no leaks. my coolant is always a little bit under full. Never had this problem until that secondary fan sensor went out.......could the secondary fan be my only problem? HELP!

billfrank85

For starters, fix your fan. It's one of the best insurance policies you can have right now.

Is your mechanical fan even spinning? The only other thing I can think of is your thermostat is stuck closed or partially closed and you have been relying on your electric fan for all of your cooling needs and it finally shot craps.

Edit: try comparing the temperature of both of your radiator hoses when you reach 210 or so on your gauge. See if they are the same, or different.

goblinish15

my main fan is spinning yes. the temp of the hoses are the same. it overheatts 1-2 times out of 10 when ideling and stopped............so how does the thermostat work. i have yet to mess with messy heating problems!

cherokee90

this is simple FIX THE FAN! its there for low speeds and while sitting still.

HighRoller

+2 on fixing the elect. fan but I'd also check the fan clutch..... You can do that by CAREFULLY stopping it while the engine is running and holding it still for a few seconds. The clutch should catch and pull it out of your hand if it's working properly. If you can keep it from spinning for more than say 30 seconds then the fan clutch is bad and isn't circulating enough air. Also if your fluid level is always just a little low you probably have air in the system. Make sure it's parked on ramps or anywhere where the front is slightly elevated to help the air escape and bring it to operating temp with the radiator cap off and be patient filling it a little at the time until it stays full.

45shutr

Just wanted to add to this comment, don't use your hand, use a stick or better yet a rolled up newspaper, so if the fan comes around and whacks the newspaper it won't damage the fan blades.

tjwalker

1. Fix/replace your e-fan. Period.

2. The #1 cause of "temp creep" at idle is a bad fan clutch. Hard to troubleshoot them with great accuracy. If it is old, get it out of there. The part is cheap and it is easy to replace.

djb383

Please, please, please, don't stick whatever into the rotating blades (engine running) of the mechanical rad fan..........doing so is just......well.......just don't. Both fans need to be functioning properly but I think your over heating problem may go beyond a rad fan(s) issue. Overheating, this time of year, in Idaho????? Even if the efan was working, I can't imagine it coming on this time of year in your location, presuming all else was good with your cooling system.

Karvin

Not sure if the XJ's are an open or closed cooling system. With my rig I can pull off the radiator cap, reach over to the accelerator cable that is running from the pedal to the carb... and adjust engine speed while watching the coolant level in the radiator. If it doesn't move, then you can assume one of two things. 1) thermostat has failed in the closed position or 2) water pump is non-functional.

Replace the thermostat, they are inexpensive and it doesn't take much time. I might also add, purchase a fail safe thermostat... one that if it goes out will fail in the open position.

Fix the electric fan, but they are pretty simplistic... so check wires and fuses to it first. (cheap replacement electric fans can be found at your local wrecking yard)

If your clutch fan is not operational this might be a the time for an "upgrade" to an electric main fan. Easy to wire up, and operate with a toggle switch mounted on the dash. It will reduce the load on your engine freeing up a bit of horsepower. Belt driven fans are also dependent on your engines RPM... some will even tell you that they become ineffective at higher RPM's due to cavitation. Going with an electric fan that draws too much juice can be counter productive... you might find yourself having to throw on a larger alternator to make up for the extra draw in power. So you might NOT see any, even if it is just a slight, increase in horsepower.

Might want to think about a coolant flush while you are at it. If you are pretty new at tinkering with engines... purchase a Chilton's manual or check one out at your local library.

Aoneisdone

clutch fan weld it! chreck water pump

goblinish15

I have only had this dam overheating problem once since summer. but during summer it was over heating quite a bit. my uncle said that my fan wasnt working because the sensor that turns on the fan went bad. I went on a drive to boise. it is 100 miles away and 2 hours away. when i got to boise the temp had started climbing. so i pulled into a gas station and let it cool off. So i went to my uncles house (he is a mechanic) which is only 2 minutes from that gas station. So i pulled in and he told me that the sensor on the thermostat had stopped working. i dont know if he is right. i want to be sure on what to replace before i go taking a bunch of parts off of a donor jeep

djb383

The entire cooling system can be replaced with all new parts for less than $250 and your uncle could install all the parts in 2-3 hours. Again, if it's runnin' hot now, it's going to be runnin' really hot again this summer. Gonna cost way more than $250 to replace a burned up motor.

goblinish15

ok. Well for starters i am getting a good flow of coolant so thats good. So if its not a flowing problem then my guess is the coolant sensor or the thermostat and thermostat sensor. there is a donor jeep near me that has those parts. So it would be free. that jeep only has 100,000 miles and mine has 247,00. so should i just swap those two things?

djb383

My point is, this time of year and your location (COLD), the efan should never turn on. The belt driven fan should be more than adequate to keep coolant well below 240-250 in your COLD ambient temps. Next summer, yes, u will need the efan but something other than the lack of an efan is causing it to overheat now, in the dead of winter.

goblinish15

also my a/c does not blow cold air if that has anything to do with it