Overheating

[henry]

My car engine overheats with the A/C on for long time. Any suggestions? Thank you.

[divace73]

Does the radiator fan turn on when you turn on the AC?

[henry]

Yes, it does.

[divace73]

Apart from checking the obvious
no coolant leaks
system is topped up properly
Thermostat is working correcly

It may be worth getting your radiator cleaned and overhauled. The original fiat radiator were never that great to start off with.
I actually have a high flow unit in mine, although I don't have airconditioning we get 40 deg days here and providing the system is sealed propery and full of coolant I never have a problem.
You'd be suprised all the gunk that comes out of your radiator when cleaned properly.

[So Cal Mark]

does it overheat in traffic or hwy driving? Or both?

[henry]

Heavy traffic, the radiator was overhauled, thermostat works perfectly, thinking about, installing auxiliary electric fan.

[So Cal Mark]

if it gets hot at idle or slow speeds, generally it's an airflow issue

[henry]

Ok, what are these issues? and How can I fixed them?

[wikkid]

I would suggest wrapping yourself in protective leather clothing, including boots and gloves and a full face crash helmet, then sitting in traffic with a throbbing, air-cooled v-twin motorcycle engine between your legs, radiating heat in all directions.

Puts a Spider's air conditioning in perspective.

And I've lived in Houston, Virginia and North Carolina, as well as NYC and Chicago in summer, so I know a thing or two about heat and humidity.

As to the mechanics, I guess if you have it you want it to work. Sounds like a need for more cooling capacity, either more air flow over the existing radiator (fan), or an improved radiator, assuming what you have is, as stated above, clean and functioning normally.

[azruss]

many fiat guys convert to volvo or aftermarket radiator fans. they are narrow enough to center on the radiator and larger in diameter.

[henry]

Any suggestions on aftermarket radiator fan model for my 1983 Pininfarina?

[Zippy]

Here is a thread about aftermarket fans with links to sources.
http://fiatspider.com/f08/viewtopic.php?f=7&t=12370

You could also try jegs.com or summitracing.com

Is there a performance auto supply store in your town? They might have what you need.

[henry]

Ok, Today I bypass the thermostat, the meter is around 190 F all the time, but when I turned off the engine, fan on, the meter goes up to 240F shows overheated, but no boiling water in the reservoir......

So I think there is a problem with the sensor or the gauge.

Comments please.

[courtenay]

I've got an '80 FI and the gauge doesn't operate when the ignition is turned off.

[divace73]

That could be because the water in the bottom of the radiator is still hot and as the water pump is not working one the engine has been turn off ceasing water flow the head will be hotter.
You should also have the two temp sender on top of your head. the front one is for the temp reading of the gauge and the rear one is like a switch that switches to the hottest part once it reached a certain temp (I don't know what that is)
I think your gauge may be okay.
If you think it is suspect, try and swap a gauge (check all the earth paths are secure as well)
See if you can compare the sender values with another. Measure both voltage in circuit, then disconnect and measure the resistance. The voltage and resistance should be higher when colder and go lower the hotter the car gets. the rear switch should have high resitance and then go low once it reached its temp setting.
I measured mine recently but think I have the results at work and I have taken the week off (My wife has just had a baby No.2)
See if somebody on this forum has similar results.
It may sound that you may need a bigger fan as stated or get a switch that comes on earlier.
You could try Marks set up http://www.allisonsautomotive.com/products.html scroll down till you get to the adjustable thermostat.
If the ambient air is rather hot, it will be difficult to cool your car down.
Hope this helps