Absolutely stumped with cooling

[Nut124]

Glad to hear you are making progress.

Are you running a low temp thermos with the low temp fan switch? If not you might want to consider doing so. If not, the fan will run a lot as the thermos wants the engine hotter than the fan switch.

[18Fiatsandcounting]

Update: everything is working perfectly! And I suppose it always was...

Great, thanks for letting us know, and happy motoring! Keep an eye on it, and I'm still perplexed as to why the bottom half of the radiator and the lower radiator hose were cold. But maybe it just wasn't fully warmed up at that point, and you had shut off the engine because of the high gauge reading caused by the goofy sending units?

-Bryan

[PilotInASpider]

Update: everything is working perfectly! And I suppose it always was...

Great, thanks for letting us know, and happy motoring! Keep an eye on it, and I'm still perplexed as to why the bottom half of the radiator and the lower radiator hose were cold. But maybe it just wasn't fully warmed up at that point, and you had shut off the engine because of the high gauge reading caused by the goofy sending units?

-Bryan

That’s exactly right Bryan. The gauge showed it going to 260F very fast and I would shut it off before the thermostat would even open. Once I unplugged one and realized that I ran it until the ‘stat opened and the fan started cycling. Neither of the temp senders seem to work that well so I’ll be replacing them. Yesterday I was idling it doing carb adjustments and it showed a high reading but the fan switch was going on and off like normal. Safe to say I trust my brand new fan switch over an old temp sender. Just got the timing and carb perfectly tuned, it runs like a dream. Also discovered I need a new alternator last night on my way home. I live in the mountains and she got me a mile away from my house before loosing battery power. Thanks for all the help!

[18Fiatsandcounting]

Excellent work, Pilot!

So it was the temperature senders all along and the radiator/pump/thermostat were actually fine. Good to know. Yes, if the temperature senders start getting flaky, you can get all sorts of erratic readings when the actual engine temperature is fine. Also, if the temperature senders happen to be sitting in an air bubble at the top of the cylinder head, the readings will be goofy as well.

I had an alternator go out one night while driving a long distance, and I kept wondering why the headlights were getting dimmer and dimmer, but everything else seemed fine. And the alternator light did not come on, so I guess my alternator was producing something, just not 12+ volts. It turns out that your battery can be pretty drained and still run the ignition system, just not anything that draws a lot of current like headlights or wipers or electric fan.

-Bryan

[TX82FIAT]

Glad this has been sorted out. You can buy a IR temp reader for $20. I've found it helpfull when gauges read hot to point the reader at the head, radiator and block to see just how hot things really are.