Summer Operating Temperature

[BiminiBlueLX]

Yesterday I changed the thermostat in my '91 5.0 lx from the stock 195* to a 180*. I live in Tucson, AZ and the high got to around 100* give or take and with 30-45mins of run time the car stayed around the R and M of NORMAL. I'm guessing that would be 200*-210* roughly. What my main question is, however, is this the correct operating temperature with those conditions listed? Am i still running too hot, or is it just from the outside temp that's causing it?

From what i heard the 180* t-stat doesn't open until about 200* anyways. So, would this be a normal summer operating temperature here in AZ?

Thanks in advance!

 

[Mustang5L5]

Well I am not in arizona, but my car runs 188* on an auto meter mech temp gauge all the time no matter how hot.

Imalso have a 180 stat, so it def opens before 200 as my car only hits 200 if I forget to turn the e fan on and let it idle for a few mins

 

[HISSIN50]

Not sure on interpolating the stock gauge - it's way too inaccurate to be useful. Get an aftermarket gauge if you can. If not, use an IR thermometer or other means of determining temps.

I'd also recommend a balanced 180* t-stat for the climate.

You will probably find that you run about 100* over ambient temps (when ambient is triple digits).

 

[BiminiBlueLX]

Fixed! I ran the car later with the rad cap off, to make sure all the air bubbles had a chance to get out, bleeding it thoroughly. The heater was on full blast for about 15 minutes during this too, since I've seen that helps. I noticed after starting the car that the coolant level was really low, so I filled it up to the rim while the car was on, put the rad cap back on and went for a test drive. She held up perfectly and stayed around 180* the whole drive.