Electric fan on the run

JL Rockies · **Posted:** Fri Dec 26, 2008 11:06 am

With appologies to Sir Paul. How easy should it be to turn the fan by hand (engine off)? I've been told that there should be resistance and if it spins freely, the bearings are shot. Mine spins very easily and I am wondering if it could be the cause of my highway heat problems.

NomadKJ · **Posted:** Sat Dec 27, 2008 6:07 am

In addition to using coolant temperature and battery temperature sensor to control cooling fan operation, the cooling fan will also be engaged when the, air conditioning system is activated. The relay is also energized when air conditioning is selected and coolant temperature is above 95° C ( 203° F), or, air conditioning is selected and battery temperature sensor is above 41° C (106°F). It will then de-energize when air conditioning is selected and coolant temperature is below 92° C (198° F), or air conditioning is selected and battery temperature is below 38° C (100° F).

LibertyFever · **Posted:** Sat Dec 27, 2008 10:55 am

What do you mean by "highway heat problems"? Is the engine running to hot or is there no heat in the vehicle?

I have some experience too with overheating but sort of the opposite, my Libby would overheat while idling or while wheeling slowly offroad in 4Lo. The clutch fan mounted on the front of the water pump would spin freely by hand with the engine hot. Once I had it replaced everything worked fine.

A general rule of thumb with clutch fans, they should spin freely when the engine is cold and have some resistance when the engine is hot.

JL Rockies · **Posted:** Sat Dec 27, 2008 11:28 am

Mine started running hot at highways speeds, perfectly fine around town. Thought that I had it licked today with a good rinsing of the radiator fins, no dice. If the AC is on it's far worse. I recently had the AC condenser fan replaced which solved the problem for a while.

I am about to drive to CO with all of my belongings in tow so it would make sense that this would be going on now.

KJ 119 · **Posted:** Sat Dec 27, 2008 11:36 am

May want to check with AZScout,I know he's had overheating problems with his CRD.
Don't know if he has solved em,but if CRD's are destined to have overheating problems,then
we should find out what others have done to cool down.

Bub

sleeve84028 · **Posted:** Sat Dec 27, 2008 12:07 pm

Stuck Thermostat?

JL Rockies · **Posted:** Sat Dec 27, 2008 1:48 pm

When I searched the CRD section for thermostat issues it seems on a diesel, the engine never warming up was an indicator that the thermo was bad.

Guest · **Posted:** Sat Dec 27, 2008 4:25 pm

NomadKJ wrote:

In addition to using coolant temperature and battery temperature sensor to control cooling fan operation, the cooling fan will also be engaged when the, air conditioning system is activated. The relay is also energized when air conditioning is selected and coolant temperature is above 95° C ( 203° F), or, air conditioning is selected and battery temperature sensor is above 41° C (106°F). It will then de-energize when air conditioning is selected and coolant temperature is below 92° C (198° F), or air conditioning is selected and battery temperature is below 38° C (100° F).

If you turn your AC on you should see the electric fan running. If not then either your fan is shot or your fan relay. That's what happened to my gaser. Now you have a crd so you might want to check if there are any differences.

Overheating at highway speeds is likely due to poor coolant circulation because there should be enough wind generated at speed without the electric fan to cool off the radiator. If you live in a cold climate your cooling fan may never need to come on. I did not even know my fan had died until the end of winter and first spring warm day. Ensure that you are not low on coolant. Also check your radiator hoses. You should be able to feel pressure in the hot input hose. If not then the coolant is not flowing and it is likely a stuck thermostat. Or if that does not fix it then it could be the water pump is faulty. Check your belts.

Guest · **Posted:** Sat Dec 27, 2008 4:32 pm

JL Rockies wrote:

When I searched the CRD section for thermostat issues it seems on a diesel, the engine never warming up was an indicator that the thermo was bad.

A thermostat just opens and closes based on temperature. If the engine does not warm up quickly then it is always open. This is not your problem since yours overheats. But if the thermostat does not open then poor circulation results and this causes overheating. I've had to replace a few on other vehicles i have owned.

JL Rockies · **Posted:** Sat Dec 27, 2008 4:45 pm

I never actually overheated, but it shoots past the 3/4 point with the AC on and just at it without. I have two fans and my radiator is behind the intercooler. The front fan is brand new and works and the bigger one behind the radiator works as well. Coolant flow may be a problem at the EGR, the hose extension I had to put it seems to be kinked.

Guest · **Posted:** Sat Dec 27, 2008 4:58 pm

JL Rockies wrote:

I never actually overheated, but it shoots past the 3/4 point with the AC on and just at it without. I have two fans and my radiator is behind the intercooler. The front fan is brand new and works and the bigger one behind the radiator works as well. Coolant flow may be a problem at the EGR, the hose extension I had to put it seems to be kinked.

i'm no expert on the EGR but from what i read that does not have anything to do with coolant flow but redirects exhaust gases back into the combustion chamber to control combustion temperature. i don't see how that would cause overheating. Some people even disable their EGR claiming better performance. See here.

By the way i just noticed your kj will look similar to my silver sport once i get my used arb put on (currently being shipped). i would like to get some RL super sliders as well.

JL Rockies · **Posted:** Sat Dec 27, 2008 7:00 pm

The EGR valve on the CRD is water cooled. When I replaced it, I had to extend the in and out hoses with joiners. One has an agressive bend and the other I can not see. The valve was replaced long before this was going on and the hoses are only 5/8th and has not moved.
I'll have a looksey tomorrow, I spent the day reinstalling my interior after a deep water crossing earlier in the month.

JL Rockies · **Posted:** Mon Dec 29, 2008 10:48 pm

Out of desperation, I took it to the Den of Thieves to have them check it out. I knew in my heart that after the 1 hour diagnostic was up, they would still have no idea why my ride only runs hot on the highway and then take the path of least resistance. But with moving day close at hand and all the packing I have to do before I get there I can't spend anymore time on this.
I was right and after $260, my Jeep seems worse than before; it still gets just as hot but now it does it much faster. They said the source of the problem was a lot of mud packed in the condenser and they got a lot of it out but the only way to get it all out was to remove the condenser which of course require the ARB bumper to be removed. They said they got a lot of it out and after a test drive, they noticed no overheating issues.

I spent a good part of Sat under the Jeep with a hose cleaning in between the radiator and the condenser and I didn't think I missed anything. I took it out onto the highway (the same one they did) and the gauge shot up to 3/4 before I even got off the on ramp.

Very frustrating.

Jeepjeepster · **Posted:** Tue Dec 30, 2008 12:55 am

Could you take the piece off the top of the rad and look down between the condenser and rad? Ive never looked at a crd so idk if its similar to the 3.7 or not.

You never said which fan you were talking about. If its the electric fan then yes, it should spin freely. A bad fan typically will not cause the engine to over heat at hw speeds but the crd is a different beast. Usually they will heat up at idle with a bad fan.

If its heating up at hw speeds these things come to mind:

-Radiator
-Water pump
-tstat
-Could that viscous heater be messing up????

JL Rockies · **Posted:** Tue Dec 30, 2008 10:31 am

The problem is I went to "the experts" when I couldn't figure it out and neither could they.

It could be something as simple as a reflash to calibrate the needle to the actual temp.

There's a pretty big shroud over the whole area and I am not sure how it comes off. I have a feeling that I am going to have no choice but to take off to The Rockies on God's good humor. Maybe the fact that it will be cold and the heat running will counteract the 36 hr drive towing 6K lbs...... Maybe.

I left the service writer a voice mail last night..... No call back so far.

tulsa · **Posted:** Tue Dec 30, 2008 11:15 am

JL,
Is there someone near you who has a Scangauge? Might help with reading the actual temp. Also if the thermostat is not fully opening the lower flow would result in higher temps under load. You might also look for a radiator cap with a thermometer.

JL Rockies · **Posted:** Tue Dec 30, 2008 11:42 am

The problem is with that radiator cap is it will not work on a CRD because there isn't a radiator cap on the radiator. There is only on the big overflow jug and the sensor will not touch the coolant so I've been told. From what I've been told, a bad t stat on a diesel will actually prevent it from warming up not over heat.

JL Rockies · **Posted:** Wed Dec 31, 2008 10:52 pm

Today I pulled the ARB bumper, condenser fan and condenser for a good hosing. I cleaned everything out as best I could and took her for a drive. I drove down the highway with the AC on and the temp gauge never went beyond 1/2. HOWEVER, I did not have the bumper or any of the associated plates so there was also more airflow than usual.
If she over heats tomorrow after the bumper is back on, I might have to investigate a more powerful condenser fan.

sleeve84028 · **Posted:** Wed Dec 31, 2008 11:24 pm

I'd like to know what happens when you do get the front end all put together.

tjkj2002 · **Posted:** Thu Jan 01, 2009 12:52 am

JL Rockies wrote:

Today I pulled the ARB bumper, condenser fan and condenser for a good hosing. I cleaned everything out as best I could and took her for a drive. I drove down the highway with the AC on and the temp gauge never went beyond 1/2. HOWEVER, I did not have the bumper or any of the associated plates so there was also more airflow than usual.
If she over heats tomorrow after the bumper is back on, I might have to investigate a more powerful condenser fan.

Or a bad clutch on your mechanical fan.

Electric fan on the run

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