Auxiliary fans in front of the radiator?

[baca327]

Hmmm I guess there is a big benefit in being able to run at full speed even when the engine is only idling. Too bad it would probably be near impossible to find one of those Taurus fans here. I haven't even seen a Taurus on Maui. Everybody drives Tacomas an 4Runners... maybe there is a Toyota product that could be swapped in.

Still though, for $150 for a new fan + cost of plumbing the system for a thermostat + having someone properly mount it, it would get expensive.

Good point. The reason everyone likes the Taurus fans is the cfm the fan moves. It does add up fast.

 

[winkosmosis]

XJs have 2 fans....one is mechanical one electric. be sure the electric comes on when you turn on the AC or the defrost. If not get a new sensor. The mechanical has a viscous clutch.....that clutch can start failing w/o you knowing. Drive till you have the engine hot. turn off and see if you can spin the fan by hand....if so you need a new clutch. Replace w/ a grand cherokee clutch from a unit w/o the tow package and you will also gain cooling performance.:victory:

I checked the resistance of the fan at 222F. There was a little resistance but it was easy to move. So I guess that's the problem, the fan clutch is bad!! Thanks for suggesting this easy test.

 

[winkosmosis]

Here is a discussion on mechanical vs electrical fans http://ecomodder.com/forum/showthread.php/electric-vs-belt-driven-cooling-fan-3365.html

Starting at post #32 is discussion of the efficiency of the two types

 

[winkosmosis]

I just got the fan clutch replaced. It's STILL overheating. It got up to 227F while I stopped to open the gate. The intake air temp was about 140F. Then I parked, turned off the engine, put on my gloves, and popped the hood as fast as I could. The fan STILL spins easily when it's hot. ******??

The tech at Sears was saying if it still overheats then it would be the water pump. If the pump is bad, does that mean the radiator isn't getting as hot, so the fan clutch isn't getting as hot as it should? Is the rad what heats up the clutch?

Higher speed driving = more rpm for the pump = more effectiveness?

 

[bobDog]

I just got the fan clutch replaced. It's STILL overheating. It got up to 227F while I stopped to open the gate. The intake air temp was about 140F. Then I parked, turned off the engine, put on my gloves, and popped the hood as fast as I could. The fan STILL spins easily when it's hot. ******??

The tech at Sears was saying if it still overheats then it would be the water pump. If the pump is bad, does that mean the radiator isn't getting as hot, so the fan clutch isn't getting as hot as it should? Is the rad what heats up the clutch?

Higher speed driving = more rpm for the pump = more effectiveness?

Geez....The whole point to the viscous clutch is for it to slip when its cold out, there by heating the engine to normal temp especially in cold climates, and lock up when its hot so the fan spins at its max capability when things are hot. You might run this by the Sears guy and ask him or her why it is still hand movable when the engines hot! I have had quite a few new parts fail out of the box.
Also check this guy out! a virtual fountain of information on XJ's. Poke around in this site and you will not only spend hours and days of looking at great cool stuff from a dude in Australia but you will never run out of projects. You also will want to visit Australia.
http://go.jeep-xj.info/
:coffeedrink:

 

[winkosmosis]

Geez....The whole point to the viscous clutch is for it to slip when its cold out, there by heating the engine to normal temp especially in cold climates, and lock up when its hot so the fan spins at its max capability when things are hot. You might run this by the Sears guy and ask him or her why it is still hand movable when the engines hot! I have had quite a few new parts fail out of the box.
Also check this guy out! a virtual fountain of information on XJ's. Poke around in this site and you will not only spend hours and days of looking at great cool stuff from a dude in Australia but you will never run out of projects. You also will want to visit Australia.
http://go.jeep-xj.info/
:coffeedrink:

So if underhood temp is 140F and the coolant is at 230F, the clutch should be stiffening regardless of water flow through the rad?

I think this weekend I'll go upcountry and drive around the dirt roads. It's a lot cooler up there so there is less risk of overheating but I'll be able to look more closely at how rpm and speed affect temp, and see what happens in low range.