Intermittent high temp reading - check gauge

[MINERALGSVT]

Just recently, my X has had a fluctuating temp gauge. Some days, it works just fine, and some days it will fluctuate between normal and extremely high (check gauge will come on).

There are no leaks and the coolant levels are normal.

With winter coming on, I just want to get out in front of it. I'm thinking maybe a loose connection? Or thermostat issue?

It's a '99 V-8 AWD.

Thanks

 

[koda2000]

Probably a sticking thermostat. You'd better replace it ASAP before you do serious damage to your engine (blown head gaskets, wrapper heads).

 

[gatzdon]

Use an OBDII reader to check the engine coolant temp as reported by the PCM.

The temperature sensor for the console gauge is separate from the sensor for the PCM.

If the PCM is reporting normal, steady temperature, then you know the issue is with your gauge and most likely a corrode temp sensor (the one wire sensor).

If the PCM is reporting the same temperature fluctuations, then it's real and as mentioned above, I would look at the thermostat (provided the coolant level in the radiator is normal).

 

[MINERALGSVT]

Thanks guys. 2 good thoughts, wish my OBD2 scanner would do live monitoring. I'll need to find one.

I'm kind of leaning on the thermostat issue because the gauge will never go high until the car has been warmed up. If it was a flaky sender, I would guess that it would / could go high at any time the key was on....

Probably a few days before I can get to it, so it's parked for now...

 

[MINERALGSVT]

Finally got around to looking at this. Went ahead and replaced the thermostat and the 2 bypass hoses / clamps.

I've only driven it a few times, but no issues so far.

Thanks for the help.