Anyone rebuilt their radiator fan before?

[MIGHTY 8]

Hello all,

It seems I've run into a somewhat usual issue with my Fiat. Recalcitrant cooling system! And like anything recalcitrant...sometimes it all works. And sometimes it don't!!

Upon initially having problems due to overheating, I recently replaced the thermostat. Drained, flushed, and bled the system. Now, it appears there may be something wrong with the radiator fan. It simply either works or not, depending on its mood. And yes, I have had the radiator "re-cored" within the past two years. Which by the way, makes it the second time, I've had it "re-cored" since I've owned the car within the past 20 years.

I thought about buying a new temp. sensor, since they're pretty cheap and easy to replace. I'm trying to remove/replace as many components as I can in trying to finally remedy this issue (If there ever is such a thing with Fiats!)

Assuming I now have replaced two of the three ingredients in this trifecta of Fiat cooling (Thermostat, temp. sensor, & radiator fan) Is there a common issue that may be affecting the fan that I'm missing here? I have, for the record, tried that grounding technique, and yes, the fan does come on at that point! Just not when the needle starts headin' north of 190F!

I suppose, I can buy a "new" one, or upgrade it to some fan from a newer car, but thought I would just pose the question here for you all..

Like always, Thank you all in advance,
G.

[Fiat88]

Doesn't sound like its the fan if you got it to come on when you manualy grounded it. I would suspect that its either air bubble in the system(have you checked that your thermostsat is opening) lower rad hose hot or its your rad fan sensor.

[MIGHTY 8]

Well,

To the best of my ability, I've religiously followed all the "tried-and-true" methods of bleeding out the air from the system. And in response to your question, yes...the lower hose is getting hot, indicating that the thermostat is opening. As it should, considering I just bought it!!

One thing my mechanic had mentioned that intriqued me was that while we were manually forcing the fan to come on (i.e. grounding it using the wires) he mentioned that said wires were getting unbearably hot in temp. indicating that the fan is drawing too much load, and is possibly getting hung up somewhere.

Like I said before, I suppose I can order/replace a new temp sensor and see where that leaves me. It just bugs me, because I've changed that part before (arguablly withing the past 5 years or so) and I would like to believe that it should last longer then that, no?

Keep em' comin'!

[majicwrench]

I would highly recommend testing parts before changing them.
How hot does it get?? I am not sure at what temp a fiat fan switch turns the fan "ON" but on a Gm with the same set-up it doesn't turn the fan on till 230deg F.

On my 72 fiat, not sure my fan has ever come on. OK it might when I am driving, maybe I wouldn't know. Mine runs just over the 190 mark on a warm day.

[seabeelt]

Its easy to test the fan - disconnect it from the thermal switch and run some jumper wires from a known voltage source and ground. The fan should start right awaw and turn quickly to high rpm. low rpm or slow start - bad fan. (Typically if the fan were bad you would get the above symptoms and probably be blowing fuses) If it works correctly go back to the thermal switch and check and clean the associated wiring grounds and connections.