Thermostat/Coolant temp

[Ktrimpe]

Was having inconsistent heat the last couple weeks. Watched YouTube decided I could change the thermostat. Installed a Napa with 203 temp. Replaced and let the truck run a few minutes. Took it for a drive and the temp got up to 235! Any thoughts? Could I have installed the thermostat wrong? I did open radiator cap thinking it would bleed any air out and closed before I drove it. Previous thermostat seemed to be 180 temp.

 

[Jason G Slabaugh]

4 of my thoughts of possibility:
1- You got a bad part
2- your gauge is off
3- trapped air wont spike your coolant temp, it'll make it read cooler than normal.
4- a normal tstat will usually ride around the 215- 220° mark

 

[Karlsweg]

You had air in the system. Run it until thermostat opens with rad cap off topping off as needed. Steam pockets form spiking the temperature .