Thermostat

[Sport]

During my plenum job recently I did a full coolant flush, water pump, and thermostat. I noticed that my aftermarket 195 F thermostat had a small hole on the side that the stock one did not have. After installing the new t-stat my truck is running around 170-175 F fully warmed up, even when working the motor hard. I'm assuming this must be because of that small bypass hole?

My old t-stat doesn't work anymore so I'm thinking I will order an OEM t-stat. Any other ideas on what could be making the truck run cold? It seems like this cold running is causing it to shift down a lot more frequently on the freeway.

 

[pajeepman]

Little hole is probably there to help get air out if the system. I have drilled holes in t-stats before, seems many come with them already now. That tiny little hole will not let enough coolant pass to keep temps that low. Does the t-stats work? I ALWAYS test mine in boiling water on the stove first. Had 1 not work.

 

[Rustycowl69]

I agree with pajeepman.

 

[Sport]

I'll pull my T-stat today to test it out in boiling water, great idea. I may also replace the coolant temp sensor to see if that helps.

 

[Sport]

It ended up being the coolant temp sensor. Once I replaced it with a brand new sensor the truck is reading 195 F exactly. Definitely helped it run better as the computer isn't thinking it needs to warm up still probably.