[Devildog]

I have a 86 Mustang 4 cil. 4 speed trans.100,000 miles.It satrted reading on the temp. gauge it hot as soon as i start the car cold.So i replaced with new thermostat,radiator cap,bottom radiator hose,radiator,water pump and two new hoses connecting to the heater core and i even put a new heater core in.And it still reads hot.so i took the thermostat out and still the same thing.i checked everything twice and no leaks.Could this be my cooling temp.sending unit,thats the last thing i can think of.Any help will do.

[OTreborO]

Originally Posted by Devildog I have a 86 Mustang 4 cil. 4 speed trans.100,000 miles.It satrted reading on the temp. gauge it hot as soon as i start the car cold.So i replaced with new thermostat,radiator cap,bottom radiator hose,radiator,water pump and two new hoses connecting to the heater core and i even put a new heater core in.And it still reads hot.so i took the thermostat out and still the same thing.i checked everything twice and no leaks.Could this be my cooling temp.sending unit,thats the last thing i can think of.Any help will do.

Sounds like you have replaced everything else.............

[Devildog]

I've replace everything so far and i'm getting mad couse i can't figure this out.So i replace the cooling tem.sending unit and checked the fuses all ok.And still the gauge reads hot but the car isn't over heating.do i need to buy a new gauge or gauge cluster?Or buy another cooling unit switch which is $40 something dollors.

[mdvaldosta]

It's either your sending unit or your gauge. Your car can't be hot when it starts cold.

[fakesaleen]

did you mtry an after market gauge and sending unit?

[GER2]

Hi, Just wanted to relate a overheating story. I have a 2001 Mustang with 191,000 miles (I put quite a bit of seat time in in the course of my work) and I have had very few problems with it. However about 2 years ago I started noticing that it would overheat when I got off the highway into stop and go city traffic. Car ran cool and the a/c ran fine at highway speed. It only happened on hot days when I was running my airconditoner. The temp gauge would start rising and the a/c would start blowing hot air. I replaced the t-stat and flushed it...that didn't fix it. It started getting worse, replaced the temp sensor...problem persisted. Put in a new high volume water pump and new t-stat, problem persisted. My mechanic then did a test on the a/c system. found a ridiculously high overpressure on the high pressure side of the system. He de-pressureized the system, and refilled it. Problem persisted. It looks like there are one or more parts in the a/c system that have failed, and need to be replaced.

[stang fanatic]

the wire from the sending unit is probaly grounding out. Is it going all the way up? Try turning the key to on but dont start and see what it does.