I have an autometer water temp gauge. My truck normally runs around 180*. Sometimes when I'm just driving easy it spikes up to 220*. Not for long and when I notice it I back off and it comes back down. It doesn't matter what the temp is outside either. Last week I did a lot of heavy towing. Pulling the grades my egts hit 1200* and the water temp never went over 205*. It seems wierd that empty it will spike to 220* but towing it barely went over 200*. I don't know if my thermostat is sticking or the gauge or sending unit is wacky. Any thoughts? Thanks.

 

I would boil water and put it in a pot, take the gauge probe and put that in the water. Use another temperature gauge and see if they both read the same. If not then your have a faulty autometer.

 

First i would try and check the gauge if possible but...

I would spend 10-15 bucks and just change the thermostat since its a 10-15 minute job anyway. Cheap, easy, and preventative maintenance. I bought a Motorad 2033-192 high flow 192*f from amazon for that price and it works great. Tested it in water like bannerd said and it was spot on. I used a 180*f gates from Geno's first and it was way too cold.

 

Thanks for the replys. I'll start with testing the gauge and sending unit. I'm sure it wouldn't hurt to change the thermostat. The truck has 316k on it and all I know is the water pump was replaced at 255k. I've read here before that people claimed the stock thermostat was better than aftermartket. Is that true? JBradley, what do you mean the 180* thermostat was too cold? Thanks again.