Wild temp gauge...

[Millsrocks]

Hi there.

i am new to the Bronco II (pretty much a newbie full stop really).
i recently bought mine off a guy on the south coast of England.
it's an ' 87 (i believe), shipped into the UK at the beginning of the '90s.

i am slowly working thru a list of faults i want to fix.

i just had some core plugs replaced in the cooling system as i had a leak.
seems to be holding coolant fine now...finger x'd,
however....for at least 10 minutes (until getting properly warmed up), the truck's temp gauge seems to creep back and forth between a third and two thirds within the 'normal' field.
why do you think this is?
dodgy temperature sensor/sender? thermostat?

any help greatly appreciated.
i'm sure i will be here quite a bit over the coming months as i roll out my list of things-to-do.

hope to hear from someone soon...

Mills.

 

[CarsonChris]

I would think thermostat. Might have one that sticking a little.

 

[Millsrocks]

thanks CarsonChris.
i am thinking of replacing the thermostat AND the sender.
can't hurt to try eh?

 

[wildbill23c]

At least yours kind of works LOL, both my temp gauge and oil pressure gauge sit at 0 all the time. Most likely your thermostat is on its way out, but the connection to the gauge itself or to the sensor may be corroded or lose, I'd replace the thermostat and the sensor both.

 

[adsm08]

Is the coolant full? Low coolant can cause erratic temp gauge operation.

 

[Millsrocks]

Thanks WildBill....i have ordered new Stat and Sensor from RockAuto.com

 

[Millsrocks]

Hey Adam08. Yep....coolant is full in rad....and half way up the reservoir. Just it replaced along with some leaky core plugs.

 

[Millsrocks]

So.

Replaced the thermostat and the Temperature Sender.
Hasn't really done that much to remedy the situation.
10 minutes of temperature gauge fluctuation, and now settles at just over the half way mark occasionally rising up to two-thirds and falling to just over half again.

very frustrating.

any more suggestions from anyone?

 

[adsm08]

Wiring or gauge. The temp sensor is a thermistor. As the temp at the sensor changes it's resistance changes and positions the gauge. If the wiring is screwy it may interfere with the loaded resistance of the circuit.

Or the gauge itself may just be shot.