engine cooling fan

[spider76newbie]

My cooling fan doesn't ever turn on, and the engine will overheat if not moving while running. I tested the fan with a 9V battery and it works. I replaced what I believe was the cooling fan relay, but it still doesn't work. I'm still pretty new at all this stuff, so some advice on where to dig and what to look for to make it run would be great. I assume there is a thermostat I should look for somewhere. But where? I also contemplated wiring it into another system that is always on while the engine is running, but decided I would try to fix it without starting a messy rewiring cob-job quite yet.

[mdrburchette]

You may have an air pocket in the cooling system or the thermostat may be stuck closed, but it will usually overheat while driving if this is the case. The thermostat is the big thing at the end of the lower radiator hose with three hoses coming from it. I would check the fuse that powers that relay. It should be the same as on my car which is the "L" fuse.

[mbouse]

also, it may be possible that the t-stat is not properly installed, with three hoses connected to it, proper re-assembly can get confusing. Sorry, don't have a picture handy....but someone else should.

also, when burping the coolant system, be sure to have the heater core OPEN and don't forget to bleed the choke lines.

I have a written procedure available to send via email:
mbouse@chartermi.net

[manoa matt]

The fan should come on even with a bad thermostat. With a stuck closed thermostat the fan would be on all the time to prevent the car from overheating.

If you jumped the fan and it works then your problem is in the wiring or the switch.

Check the ground connection at the grounding pod located on the drivers side inner fender at the front of the engine. There should be a thicker black wire attached to the ground pod, "bottle cap". Make sure the female connector is secure to good wire, if not replace the female spade connector. Also make sure the ground pod is clean on the spade terminal and on the back mounting surface to the fender. All connections should be clean bright metal.

You mentioned that you changed what you thought was the fan relay. The fan does not have a relay in the wiring system. You might have changed the fan thermo switch.

The fan thermos switch is located at the lower drivers side corner of the radiator. Depending on design the switch will have two wire leads or two male spade terminals. If you take the two wires leading up to this switch and connect them the fan should come on even with the engine off and the key out of the ignition.

If it still doesn't work then the problem might be in the wiring. You will need a wiring diagram to trace the lines.

Also check all your fuses.

Matt

[mdrburchette]

Matt, I wonder what year they discontinued using a relay for the fan? My 72 has one that is linked to the fan and sender and gets it's juice from the fuse panel. Are you sure the fan will work with the t-stat stuck closed? The coolant cannot circulate through the radiator when the t-stat is closed so the sender will get a false signal.

[So Cal Mark]

76 should still have a fan relay, and the fan WON'T work if the tstat is stuck closed. The water in the radiator never gets hot enough to activate the fan. Just hook the two wires together at the fan switch in the rad. If the fan turns on then you know all of the wiring is okay. Then you have to look at whether you're getting circulation through the radiator. If the bottom of the rad is getting hot, then you have a faulty fan switch. If the bottom of the radiator isn't hot then you have a faulty stat or an air bubble in the system

[spider76newbie]

Thanks for all the advice. I haven't been back out to work on my car in a while, the weather has been really cold and I don't have a heater in the garage. It was a really nice day today so when I had a little free time I went out to do a little tinkering.
As far as having or not having a relay goes, I replaced the one in this picture based on the following wiring diagram I got online somewhere.

I tried shorting out these wires -

That were connected here on the radiator -


Is this the grounding location on the driver's sidewall of the engine compartment that was mentioned? I haven't tried to clean it up yet, it's a little hard to get to, but I'll get in there soon enough.


The radiator definitely gets hot and water is flowing through it, you can see it with the cap off when the car is running.

[So Cal Mark]

have you checked the fuse box? A common problem is loose, corroded fuses. Remove the fuses, wire brush the contacts and squeeze them together for tightness and reinstall the fuses

[mbouse]

disconnect the battery before attempting to clean the fuse box contacts. ESPECIALLY if you are gonna use steel wool, or are four thumbed like me.

[spider76newbie]

Ok, my problem is identified. Thanks for the help.
It is definitely the switch in the radiator. I had tried shorting it and nothing happened. Someone said it would then come on if the switch was bad even with the key off, so I never tried turning the key on. Today I went to start up the car which I haven't done in a while because it was trapped in the garage and I didn't want to fill the garage with exhaust. When I tried to start the car the fan came on, and it actually drew enough power that I couldn't start the car until disconnecting it. I'm planning on trying to order a new switch tomorrow from NAPA unless anyone has a suggestion of somewhere to get a better quality part or a better price.
As my technical skills are currently fairly limited I imagine that I'll need some help with the install of the new switch.

Can anyone suggest to me what the best hard copy or digital rebuild/repair manual for this car would be?

Thanks again.

[mdrburchette]

IAP has the fan switch for $9.75. I would check the Fiat vendors. You'll usually find they are more reasonable, even with shipping, than a lot of chain stores.

[rlux4]

The only manuals that I'm aware of are the wiring, carb, and FI diagrams from Brad Artigue. The repair manuals are only in book form. Like I say, that I'm aware of. Ebay, Amazon, and most of our regular vendors sell the repair manuals. You should get at least a couple as you go along, there's nothing that has everything in it, so sometimes you'll need to consult more that one for a particular piece of info.
Ron

[So Cal Mark]

after replacing the fan switch, you'll need to bleed the air from the cooling system in order for the thermostat to open

[FMO]

Hi!

I have an another problem. When I drive the car with an open heather core, the temp is ok . But when I close it, the temp raise immediately?? Why is this happening? I have bleed the care for ages, and everything looks ok.

regards

Fred Michel

[rlux4]

A heater core is basically a little radiator. When it is open the heat you get in the cabin is being taken out of the coolant water. If it's closed the radiator is the only way to dissipate heat. If your radiator is not functioning efficiently (clogged up, or has bypassed tubes) then you're not getting rid of enough heat with it alone. First step would be to check that your thermostat is opening. Does the bottom radiator hose get hot as your temp gauge approaches 190 deg. F? If your thermostat is OK, you may have a problem with the radiator.
Ron