Thermostat in 1995 GT

[Brian D. Miller]

My 1995 Mustang GT has been approaching 230 degrees on the highway in our hot NC weather. The air dam is in place, a new Mishimoto radiator shows no hot/cool spots, and a high-performance water pump have not reduced this temperature. I had a 195 thermostat in it. With the thermostat completely removed, the temperature stays under 200. Is there any reason I can’t drive it without a thermostat (at least until winter)?

 

[ttocs]

you should test to see if the fan is going into high speed mode

 

[Wmac]

How are you measuring temperature?

Just for reference, low speed fan turns on at approx 208, off at around 198. Hi speed on about 223, off at approx 218.

 

[Brian D. Miller]

Aftermarket temperature gauge.

 

[Wmac]

Anyway to check its accuracy?
Is it a mechanical or elec gauge?

Had a very similar problem few years ago. Popular and expensive full swell elec gauge. Scan tool revealed that the aftermarket gauge was high by about 7%.

Now have different brand that are much more accurate.

 

[ttocs]

The temp gauge works by reading the voltage change across a thermistor, or a resistor that its resistance changes with temp. It is a very simple and can be an accurate system as long as all the connections along the way are still clean. If some corrosion developes, that will change the resistance reading and cause it to read incorrectly. The way the temp gauge just pops on the top like it does lends itself to building up some corrosion over time and it would not be a bad idea to remove the wire on the top and use a wire brush to clean the top of the sensor as well as inside the harness/connector as much as you can.

 

[Wmac]

^^ if he has an aftermarket electrical gauge. If its mechanical, it should be somewhat accurate.

A scan tool is the cats azz for checking accuracy.

Are both (2) lower shields/air deflectors in place?

Like you suggested in post #2, check hi speed fan operation. Also check the connector at the fan, its prone to melt-down. (maybe it has the "circuit breaker"?)

 

[HittingtheCurves]

My 1995 Mustang GT has been approaching 230 degrees on the highway in our hot NC weather. The air dam is in place, a new Mishimoto radiator shows no hot/cool spots, and a high-performance water pump have not reduced this temperature. I had a 195 thermostat in it. With the thermostat completely removed, the temperature stays under 200. Is there any reason I can’t drive it without a thermostat (at least until winter)?

You can run it without a thermostat but it is not necessarily the best idea. If the water flows to fast it will not be as efficient at heat transfer. If you want to stay without a t-stat gut one and leave the ring to add some resistance.