Still overheating...could this be anything besides thermo

[majicwrench]

If it is opening it is likely fine, you are not going to be able to tell at exactly what temp it is coming open. In your OP, what do you mean by "STILL not cooling properly"?? Does fan cycle on and off? Are you having a particulair problem?? Were you having a problem BEFORE the repairs?
Keith

[beachspider]

If it is opening it is likely fine, you are not going to be able to tell at exactly what temp it is coming open. In your OP, what do you mean by "STILL not cooling properly"?? Does fan cycle on and off? Are you having a particulair problem?? Were you having a problem BEFORE the repairs?
Keith

My stovetop test was repeated five or six times with similar results. Is it really possible that the test could be that much off?

The fan is working fine. I have let the temperature gauge get half way or so between 190 and the red zone before shutting of the engine. At this point, the lower hose is still cold. I believe the gauge to be accurate as while it was on the shop I watched mechanic read the temperature. With the gauge just a bit above 190, it read 198 at that time. Once I turn the engine off, if I feel the upper part of the lower hose it begins to feel warm. I'm thinking that once the water isn't circulating it's getting just hot enough to finally trip the thermo but obviously way too hot for proper operation. Does this logic make any sense?

[majicwrench]

Does the fan cycle ON and OFF??

Did you have an issue before all these repairs?? You said "still" in your OP.

A mechanic was checking the temp?? What did he have to say about your issue??

What make you think your test of tstat is "off"? IF repeated 5 or 6 times and t stat opened each time it is likely fine.

Keith

[courtenay]

Have you tried disconnecting the wire to the temp sender in the block that "spikes" the needle? On my '80, it's the one closest to the fan. When I disconnected that one on my car, all my "overheating" problems went away.

[beachspider]

Does the fan cycle ON and OFF??

Did you have an issue before all these repairs?? You said "still" in your OP.

A mechanic was checking the temp?? What did he have to say about your issue??

What make you think your test of tstat is "off"? IF repeated 5 or 6 times and t stat opened each time it is likely fine.

Keith

Fan does cycle on and off...did have a similar issue before...mechanic didn't have any ideas really but Fiats new to him...was thinking thermostat was off because of temp it opens...

[beachspider]

Have you tried disconnecting the wire to the temp sender in the block that "spikes" the needle? On my '80, it's the one closest to the fan. When I disconnected that one on my car, all my "overheating" problems went away.

So this could all be a faulty wiring issue?

[beachspider]

The fact that thermal temp indicated 198 degrees when gauge showed just past 190 degrees leads me to believe there's more to it than that. Right or wrong, that's the basis for me trusting the gauge.

[majicwrench]

If fan cycling on and off hot water is getting to the radiator and getting cooled enough to shut off the fan. I'm not sure you have a problem...
Keith

[beachspider]

On rethinking this, I don't think the fan cycled on and off. It came on, but, because temp was rising and higher and higher and lower hose staying cold, I shut off engine while fan still running. Sorry for the misinformation.

[azruss]

the sensor for turning on the fan is in the bottom of the radiator. If the stadt isnt opening then you are getting no flow out of the bottom of the radiator and it should be too cold to turn on the fan. If the stadt checks out ok, you need to make sure the orientation is correct. This is easy to screw up. the valve should be in the section going to the bottom of the radiator. If you are convinced that this is all proper, then maybe you've got a water pump issue.

[4uall]

like this

[beachspider]

The radiator isn't stock. It is one of Mark's aluminum radiators. The shop installed the fan sensor in the upper radiator house per the fan manufacturer's instructions.

[beachspider]

The stat was installed correctly and water pump is new.

[beachspider]

Got a second new thermostat and tested it. In pan of water, started opening up at 175-180, fully open by 190. A 25-30 degree difference in that same pot of water for the two thermostats. Installed and car is cooling as it should. Thanks for all the advice.

[4uall]

Glad to hear it all worked out for you