Erratic temperature gauge on 1990 Spirit w/ 2.5

I am have not tried that yet. If the gauge does climb, and the fan does
not turn on, Is it most likely the sensor or a relay?

If this occurs, can I then disconnect the sensor which will hopefully
cause the fan to come on, and the guage to drop? If I turn it off in
this state, will the fan stay on, and potentially drain the battery?

Thanks,

-KM

 

If the fan does not turn on the gauge will climb!!! Try it first.

when the key is turned off the fan will turn off too.

I have a golf trip all next week and will not be able to get back with you
so if you want me to try and help do it now.

 

sometimesd bacflushing will work and watch the pressure it can and will blow a
weak heater core i have used snow bowl toiletbowl cleaner to help remove some of
the deposits in the core but it should only stay in about 10 minutes and make
sure you reflush it after both directions

 

Okay Glenn, I gave it a try this evening. It was about 45 degrees
outside. I let it idle until the gauge got to just past the 2/3 point
in the *normal* range. The fan did not come on.

I let it set a few more minutes, and the gauge climbed a little
further, but not outside the *normal* range. The fan still did not come
on. I then disconnected the wires from the sensor on the thermostat
housing. At this point, the *check engine* light came on, along with
the fan, just like you said it would. Once the fan came on, the guage
moved down to the 1/2 point in the range.

My questions are:
How much higher would the gauge have to reach before the fan should
come on? Is the sensor not working correctly?

I then took it for a drive on the interstate, and the guage remained at
the 1/3 point in the range, so it seems to stay cool so long as it is
moving.

Thanks for all your help. I hope you enjoy trip.

-KM

 

I don't know how accurate your gauge is. It may not have gotten hot enough
to turn the fan on. In order to check it properly you would need to have a
scan tool connected to the vehicle and monitor the coolant temp sensor. When
the coolant temp sensor hits 212 degrees the fan is supposed to turn on. At
least you know your fan circuit is working. I don't think you let it sit
long enough to tell if the fan came on. My guess is that the fan works and
your heater core is stopped up.

Good luck, im on my way out

Glenn

 

I replaced upper and lower radiator hoses late this summer when I had it
flushed, and refilled with fresh anti freeze.
New hoses have made no difference in this weird little problem.

D

 

This is long after the fact, but I just saw this posting and thought it
was interesting - is this still even viable to reply? I had an '89
Dodge Spirit with 2.5 Turbo and would be driving down the highway and
the temperature gauge would suddenly pin to HOT and maintain that
position for about 15 seconds and then return to NORMAL, which was
about 2 needle-widths short of half-scale. After a while I noticed two
things: 1) ALL of the gauges were doing this funny thing, not just the
temperature gauge (fuel & oil pressure too). 2) The engine never
changed tone or ran any different while this was happening. Are you
sure this isn't the issue with your '90 Spirit? Also, around 1972, I
was driving a 1 ton Dodge truck for my company and noticed the same
thing with all the gauges (except ammeter) would suddenly swing way
past full scale, stay there for 10 seconds and then return to normal.
Seemed to happen most often while driving down the highway, but also
sometimes parked at a stoplight (whenever you might notice it). I
always thought it was just junky Chrysler instrumentation....