Coolant temperature on a '67 DeVille

[Julien Abrahams]

Dear all,

Just a short question on the 'normal' coolant temperature on a '67 DeVille after the car has driven about 20 miles. Ever since I replaced the temperature sending unit(a couple of years back) the temp gauge goes to about the half way mark after the car has warmed up. That is also where it stays (with outside temperatures around 85 degrees).
I have measured the temperature with an infrared thermometer of the upper radiator hose right near the thermostat housing getting around 175-180. Lower radiator hose is around 160. (I just got the temp gun, so I was just curuous).
My guess is that the sending unit is a bit off. What do you think?
If the car is not overheating (which it isn't) I can live with that. Thanks in advance.

Julien.

[Big Fins]

Unless the sending unit in the block is calibrated to the gauge, you are going to experience incorrect and/or differing readings on the gauge in the dash. The temperatures that you are getting via the IR thermometer look correct, indicating you are getting flow through the radiator and the block itself.

Have you tried a mechanical gauge with a matching sending unit? I know parts aren't as easy to obtain where you are and threads may be different. Getting a new old stock original sending unit that is used with that dash gauge would be best, but probably difficult to find.

I would say that halfway on the gauge is acceptable. You can smell an overly hot engine and your IR temperatures are telling you what is real. I wouldn't be too nervous about it. Enjoy the car!

[Matti R]

Unless the sending unit in the block is calibrated to the gauge, you are going to experience incorrect and/or differing readings on the gauge in the dash.

How to calibrate the gauge? Or how to check that sensor is giving correct resistance? I have not found any data in Service manual.