Engine Operating Temperature

[wn6wtv]

I just had all of the fluids changed on my "99 4WD, and the tech said that he thought the thermostat was not opening all of the way since he could only get the engine up to 180-185 degrees. I have the trailer towing package, so I have lots of cooling. The tech said normal temp should be 206. I always kinda thought a cool engine was a happy engine, within limits....and it's not like the thermostat was stuck....Any ideas???

 

[MO Viet Vet]

Where was he getting his temp info? from the dash gauge? A scanner? Temp gun?

 

[wn6wtv]

Sorry, one tries to post all relevant info. He was measuring the coolant at the radiator where the cap fits (the neck?) using a thermometer and the engine at idle.

 

[MO Viet Vet]

He should measure with a laser temp gun at the thermostat housing area. More accurate reading. If the thermostat is old enough it is never a bad idea to change it when the system is drained.

 

[lesterl]

^x2

 

[wn6wtv]

Well, thanks one and all for the help. You've given me an idea, which is to jack into the ODB-II port and see what the truck itself thinks the coolant temp is. I'm being to suspect that I've got a stuck open thermostat, which i can monitor by comparing coolant temp to upper rad hose temp. Let you know what I find.......

 

[MO Viet Vet]

Great. Always want a closure to a thread to help others.

 

[lesterl]

Thermostat normally is 196*

Aftermarket "performance" thermostat could be a 180*, I bet this has been installed.

In my experience if the thermostat is stuck open, the needle on the temp gauge doesnt come up much... runs pretty cool.....

 

[MO Viet Vet]

^X2

 

[adam74]

I'm thinking a 180 stat too but the coolant in the radiator is gonna be cooler than whats in the motor. that is in fact the purpose of the radiator.

 

[MO Viet Vet]

Use the stock temp thermostat, 196 degrees. The radiator is where the hot coolant is transferred to from the engine to dissipate the heat before the cycle begins all over again and the next coolant from the hot engine changes places and starts to cool. Aluminum radiators dissipate heat better and faster than old style radiators.

Do this. Heat the oven with a pan in it and then touch the pan and it is hotter than Hades. Put a piece of aluminum foil in there and heat it and when you pull it out you can touch it with your hand within a minute or less.

 

[lesterl]

Use the stock temp thermostat, 196 degrees. The radiator is where the hot coolant is transferred to from the engine to dissipate the heat before the cycle begins all over again and the next coolant from the hot engine changes places and starts to cool. Aluminum radiators dissipate heat better and faster than old style radiators.

Do this. Heat the oven with a pan in it and then touch the pan and it is hotter than Hades. Put a piece of aluminum foil in there and heat it and when you pull it out you can touch it with your hand within a minute or less.

^DISCLAIMER, DONT DO THIS, you will burn yourself. This is an example not to be actually tried....