Player0

A while back I posted that I was mysteriously loosing coolant. I did a pressure test and that came back good. Well I think I understand why now. I overheated today in a parking garage. I had just topped off the coolant too. I let it cool down, filled it with water, and drove home, and everything stayed remarkably cool. But I finally noticed that at stop lights, the temperature would climb.

So I started to suspect cooling fans. Got it home, parked in the driveway, sure enough, neither are spinning. Looked back in the cab, just idling there a few moments and the warning light came on. And sure enough, after shutting it down, after a few minutes, the overflow tube started spitting out coolant. Not a lot, but there's my 'slow leak'.

Both fan fuses were blown. I just changed the fan switch not too long ago. The relay 'clicks' when I plug a new fuse in. But the new fuses immediately blow. Both fans feel very 'stuck'.

Both fans worked last fall, did I really experience both fans failing at once?

cruise98

Here is a diagnostic for the cooling fans...

Cooling Fan Electrical System Diagnostics

The fans are controlled by the cooling fan relay which is in turn controlled by the thermo switch, and the a/c system. Whenever they are closed, both fans should run at the same speed at the same time. If only one is working or you only get high speed operation, there is a problem.

You should always have power available to the relay, so the fans can run at any time. Remove the cooling fan relay. It is the large rectangular silver relay in the back of the panel. Check the diagram on the fuse panel cover for the exact location. All of the following checks can be made at the fuse panel. You will need a bright light to see the markings on the fuse panel.

1. In the Bosch world, a terminal designation of “30” means it is un-switched battery voltage. Check for voltage at positions 30 M1 and 30 M2. You should get 12v + at both positions. If no voltage, check the fuses. If the fuses are good, you have serious issues and will need a wiring diagram to go further.

2. Check for continuity between ground and the temp switch positions "TS" and "TF" on the fuse panel. If you have continuity, the thermo switch is calling for fan operation. If the car is cold, the thermo switch is bad. Conversely, if the car is hot and there is no continuity, the thermo switch is bad. They generally fail safe and run the fans all the time until the battery is dead.

3. Fabricate a jumper wire with flat blade connectors on each end, and a 20a fuse in the middle.

4. Connect the jumper between M1 30 to M1, the drivers fan should run at high speed. If the fan does not run, check for voltage in the connector at the fan motor, if you have voltage but the fan does not run, replace the fan motor.

5. Check the passenger fan by connecting the jumper between M2 30 and M2, the passenger fan should run at high speed. If not, the same drill.

6. Next connect the jumper between M1 30 and V1, the drivers fan should run at low speed. If not the resistor or wiring is bad. Check for voltage at the radiator fan connector and then check the resistance across the resistor.

7. Next connect the jumper between M2 30 and V2, the passenger fan should run at low speed. If it does not run, check the wiring and resistor.

The other positions on the fan relay are:

X = battery power to the logic board in the relay
31 = Ground for the logic board in the relay
AC = AC freeze protection switch

If the car is still running hot and the fans are working properly, you have other issues, like a clogged radiator, water pump failing, air bubbles, bad thermostat, or a bad head gasket.

Player0

Thanks for the info. Granted, I haven't traced the electrics just yet. When I move the fans by hand, I really have to struggle to move both of them. They feel quite seized, almost like the fan shroud is somehow coming in contact with the fins or something. Unfortunately work dictates that I don't get to really take a good look yet, and I didn't see anything in the way of the blades when I was trying to spin them by hand.

Are the fan motors serviceable or anything?

Player0

Oh no

It really *is* binding on the fan shroud. The radiator support on the bottom got pressed up, the radiator bottom seems kind of bent, and the shroud is twisted, causing both fans to bind on the shroud.

This damage occurred over the weekend when lowering the car down off the jackstands after replacing the suspension. I made a rookie mistake, as a rookie, and lowered one side a bit too far causing the car to go unlevel, tipping the thing back off the stands.

I checked underneath for damage and I didn't see any, but I wasn't looking up front I guess and I missed where the front jack stand, usually under the front cross member, had tipped back and the legs landed under the radiator. I thought the car and slipped cleaning off of that one.

Ugh. Flame away.

It doesn't look 'too bad'. Nothing looks too bent. The radiator isn't leaking. I just need to unpinch the shroud. Or... maybe it will need a new radiator. Not entirely sure how the fan mounting works or how I'll be able to 'stretch' it back in to being straight.

Ben951S

Fix the block, get them spinning by hand, and replace the fuses. Might be okay. I had a stuck fan, WD40, broke it free, been good 6+months.

cruise98

That would make the fuses blow! Time for some quality/quantity time under the hood.

Player0

Well I loosened the top 3 fan shroud bolts and removed the bottom three and i was able to bend the plastic back in to shape enough to get one fan going. So the cars not over heating any more. I can't seem to get the right side fan to spin freely though and I'm not sure why as the plastic is all loose. I think the fan shroud bolts must really help to hold the shape of the shroud, or maybe the heat has warped it or something.

The radiator is bent up pretty good. I'd have to remove the radiator and the shroud to correct any of the damage I think. But I think I'm going to have to get a new radiator. I don't know if it will survive being bent a second time.

I need a lift!