engine temp light?

[jl1217]

hows everyone doin?
i got a question about my 91 ford e-350 7.3 idi
when i drive it for a little the engine temp light comes on in the instrument panel.
i changed the antifreeze and the oil.
what could be making that light come on is there a sensor somewhere that could of went bad?
my antifreeze gauge needle sits in the middle of the gauge
and my oil guage needle is almost at the hot reading
thanks for the help
justin

[jl1217]

also i replaced the thermostat forgot to mention that

[Plywood]

You can buy infra-red pointer thermometers cheap these days and see what temp it is really at.

The sender for that light is just an open/close switch. To test it you would actually have to heat an antifreeze/water mix since plain water won't get that hot.

[chuckster57]

Originally Posted by jl1217

also i replaced the thermostat forgot to mention that

What thermostat did you install?

The specified/required thermostat does not contain an internal bypass, since the bypass is located in the cylinder block. Whenever the thermostat is replaced, it is mandatory that only Motorcraft E5TZ-8575-C or Navistar 1807974C94 thermostat be installed.

[trampsdieseltruck]

like chuck said sounds like the thermostat.i replaced mine 2 months ago with the Navistar 1807974C94 thermostat and my truck temp needle does not go over the "N" on normal.how old is the antifreeze?

[jl1217]

not sure what type of thermostat but the antifreeze is only been in the truck for a day

[cdnsarguy]

I would try to find out if there is an airlock in the system......... engine off remove the coolant hose to the top of the water pump. try to fill it more.

When you had the thermostat out did you see a little check ball in the upper coolant manifold... see my pics. That little guy is for purging air from the system.... it should be there. One trick I use to find out if mine is working is on a cold engine, squeeze the upper hose fast and release.... do it a couple times and you should hear the ball rattle faintly.