Electrical 92 5.0 5 speed thermostat issue

[Jvshouse]

Hey my 92 5.0 5 speed mustangs thermostat stopped working. Car blows heat and both radiator hoses get hot. I noticed after i turn car off the gauge starts raising to operating temp. It never has gone over 2nd bar even when it worked. Any idea what to check. Thanks!

 

[mikestang63]

if your thermostat stopped working, I would check that

 

[JD1964]

Thermostat may be stuck open. If I had a failed thermostat, I'd rather it be stuck open than stuck shut. Anyway, since you said it stopped working I assume you know that it was working previously. I mention that because sometimes people remove the thermostat entirely. I would never recommend that but that condition could also explain the symptoms you described.

 

[Jvshouse]

Thermostat may be stuck open. If I had a failed thermostat, I'd rather it be stuck open than stuck shut. Anyway, since you said it stopped working I assume you know that it was working previously. I mention that because sometimes people remove the thermostat entirely. I would never recommend that but that condition could also explain the symptoms you described.

 

[Jvshouse]

Yea just the gauge in car stopped working. When i turn car off after and remove key the gauge starts slowly going up to normal operating temp. Put key in and turn for power and gauge drops.

 

[Mustang5L5]

Temp guage sender is located on the driver's side front corner of the lower intake manifold. Simple single-wire slip on connection on top. The sender is pretty cheap, so i'd probably start by replacing it.

Bottom left in this picture

 

[JD1964]

Also, you can test the gauge and related wiring by this method. Unplug the wire from the temp sender. Ground it to the block. Turn the key to the run position and the gauge needle should peg all the way full hot.