My WJ has 215K miles on it with the original fan. It stays cool as long as I'm underway down the road, but as soon as I stop and idle for a minute or 2, it heats up to around 240*. It's running, but doesn't seem to put out the air blast it used to on high. Hotwiring it doesn't seem to make a difference. The radiator is new in the last 6 months and the fins on the A/C condenser are clear enough to see the engine thru with a droplight. The blades turn freely by hand but take a second to spool up. I think it's time for a new fan.

There have been many posts about this low speed overheating problem and I think I've stumbled onto a reason. Thoughts?

 

Dave1123, What's the status of the viscous fan clutch and the blades of the mechanical fan? Those simple things may also need attention. Do you have mesh screening behind your grill? Did you include other new stuff with the radiator (T-stat, full fluid replacement, water pump, etc.)? And yes, a slow-to-spool-up electric fan is a sure sign of an impending demise, but to be sure it is the fan then riddle me this. Was it slow-to-spool when hot-wired, when running via the control circuitry or both?

 

I have the 4.7. I have never bought a high mileage vehicle before, and I have owned plenty vehicles. This one came with 137,000 k on it. At approximately 149,000k my electric fan did me a huge favor and threw a blade into perfectly good radiator. Its nylon and subject to heat,and flexing and I thought the bearings or motor would give out first. I have never put 200,000+ miles on any vehicle, but I would never allow any of the external wearable parts to go that long without replacing them even if they work. I broke my own rule and I should have known better. I say you have done pretty well with this fan , if its the original I would change it regardless so you don't end up like I did..

 

What Motor?

4.0? , Do you have the electric fan only setup?
If so then yes change the fan...

Also you mentioned jumping the fan, was your relay not working?

Cooling systems are simple...
Radiator, Water Pump, T-Stat, Cap, & Fan...


Whenever, I start have cooling issues on a vehicle I always replace the Cap, T-Stat, and clean the radiator, because their easy to do, cheap, and good practice.

 

Just for information, the fan blades are glass filled high temperature nylon. Just about the most durable plastic in the industry. Yes, it's a 2000 4.0 without the tow package and just an pulse-width PCM controlled relay for a single electric fan. Once before, the relay crapped out and I jury-rigged a direct connection from the ignition circuit to make it run on high until I got a new relay. That sounded like a tornado trying to get thru a keyhole, but it kept the engine cool. Now it starts slow and doesn't quite move as much air. Just using the normal control, if I let it idle or drive slow, like on my newspaper route, it gets up it 240* quickly. driving normally to 40 or 50, it runs at about 200* like it's supposed to. Since I've wired it to a relay and switch, It'll stay below 220* if I idle or drive slow.

The entire cooling system is clean, radiator is new, water pump, thermostat, hoses are less than a year old. The A/C condenser is clear enough to see thru so there's no air blockage from that. I've never overheated it that wasn't related to the electric fan or it's controller. I used to brag about the fact that it always stayed between 195* and 210* regardless of outside temps.

I'd just like to add the overflow reservoir level has remained stable since I replaced the radiator. That's a miracle in itself!

I have to say something else for the guys with high mileage jeeps. I've had no problems with electrical connections until it crossed the 200K mark. Now I'm getting intermittent lighting problems. The radio refused to illuminate for a while and now has come back on. The shifter panel flashes on and off once in a while, and the courtesy lights don't always come on when I open the driver's door, but will once the key is turned on. These are just minor, but I can't wait until it's engine controls that are the problem. I guess it's time to separate and clean all the connectors. Oh Joy!

 

Dave: When I had my E Blade come apart, I became aware that there was a recall for our year Jeep for that very reason. Apparently, they started failing early in service/production. I contacted Jeep and even though mine was in the year and in the production period my VIN was not listed as part of the recall. It was tough for me to make a case and complain on a 17 year old car so I was stuck funding the new radiator and E Fan. So, who knows?

 

I know it's got to be the fan because today, the air temp only got to 67* this morning and my jeep stayed within normal temps without the switch. When I had the near-overheat, the air temp was 89*. When the air was 82*, the switch kept it at 220*. That proves to me that it's airflow that's the problem.

 

Time to swap in a Taurus fan lol. That thing will suck a cat through the radiator hahaha. Sounds like you got the problem narrowed down.

Max

 

i got tired of messing with my electrical fan and dropped a mechanical fan from a 4.0 explorer/ranger and it solved my over-heating problem, cost me $17 at the local junkyard.

 

If you're talking about a direct drive fan, I can see that working, but you're losing about 10 hp of engine output, don't ya know? The additional load on the alternator isn't that much.

 

its not direct drive its a thermostatic fan clutch and i very highly doubt its going to burn up 10 hp, plus its a 4.0 so im not as concerned about making hp as i am about keeping the engine cool more efficiently

 

Well whatever floats your boat, I guess. My electric fan has kept the engine within 195* and 210* for 200K miles without any problem in any kind of weather or temperature except when the relay died and now the fan motor finally wore out. I can't ask for more than that! My main concern for this post was to make people aware of a potential problem with the loss of air velocity caused by the motor loosing it's pulling power over time.

The clutchfan on my ZJ wasn't as good as this fan. In heavy traffic I sometimes had to slip it into neutral and rev it up to keep it cool. Or roast my butt with the heater on!

 

UPDATE: I just replaced the original fan with a Dorman and the temp needle doesn't move more than 1/2 needle-width either side of the 210* center mark. BTW, I had to replace the wire harness plug because it was not there since I got the jeep. Dealer-only item, $35. Out of 7 WJs in the junkyard, not a one had a plug. It only takes 5 seconds to disconnect it, but 1/2 second to cut it. No fans or radiators either.

I ordered a Stant rad cap from Rockauto. $2.17 and $5.99 shipping! I didn't need it right away and it saved me the gas and trouble of hunting one down locally. The one I replaced was a Stant with 100K miles on it and still holding pressure.

 

Any reason why you bought a Dorman? I always considered their stuff on the chepo side. I bought a 4 Seasons E Fan, when mine went out. I didn't know it at the time, but HAYDEN also offers one. If I had known. I would have gotten one of theirs.

 

I deal mostly with Rockauto and it was a medium priced unit and I've used Dorman stuff before without any problems. I spent a lot of money on next day delivery so I didn't buy Mopar or AC Delco.