having the temp read the water temp in the head or take the reading from the outlet water neck (intake)? just curious why the gauge and the outlet neck temp are so far apart. the guage reads 220 when a digital temp gauge says the the neck is 177 (180 thermostat). i think i would rather see the actual temp going to the radiator. any thoughts?

 

You want to know the temp in the engine, not the radiator. The radiator temps are always cooler. We don't care how hot the temp in the radiator gets, thats a $100 part to replace. Engine seizing due to heat is much more expensive.

 

right about not caring what the radiator temp is. i dont. i want to put the sensor in the manifold water outlet neck going to the radiator. why have a 180 thermo in the neck when the actual engine water temp is 220? what is the temp of the engine coolant where the cts is located? lot of temp differential between the two locations.

 

The driver cares about whether the engine is hot enough that the heads are about to warp, so the gauge sender is in the head. The ECM cares about whether the car is up to operating temperature and the thermostat is open, so the CTS is in the water neck.

 

So are you saying you think you have a bad thermostat (if it's not opening at 180)? Replace it.

 

no, just want to get an accurate engine temp is all. temp reads 177 (infared reading) at water neck, but the gauge will read 220 all day long. guage will fluctuate when the fan kicks on. now as to whether or not it is accurate, who knows. just seems to be a big diferrence in the two temps. why not read the temp coming out of the engine instead right at the head. the older cars used to read temps in the manifold and not the head. the temp sensor is new also. gauge could be the problem. might stick a mechanical gauge on it temperarily just to see.

 

Guess the most heat is in the head. That's the combustion chamber, the exhaust, the piston friction, etc all in one place.