The Stovebolt Site Forums The Shop Area General Truck Talk Which temperature gauge is right and ZIZ is bad.

1946 1/2 ton Chevrolet.

I have noticed some 41-46 trucks have the little red 'overheat symbol' for the temperature gauge. Mine does not and I've seen about the same amount of trucks with and without the red overheat bar.

Any ideas which one is correct? Maybe both and different factories made both? Maybe a question for the ages.

As my friends say about my truck, getting close to ZIZ is bad (rhymes with fizz, meaning 212).

See pics here. Mine is the one in the lower left corner, the gauge itself is from Jim Carter (which includes red warning bar), the other is a random example I found on the net. A picture is worth a thousand words to explain what I meant.

Temp gauge examples

Thanks Stovebolters!

I thought maybe one was for the passenger car or other model but I looked here GM Parts Manual and couldn't figure it out. Someone will happen along with the answer. Now I'm interested too!

Does this mean Stovebolters have been stumped?

The "212" represents "too hot" on a zero pressure cooling system. If a pressure cap is used, the boiling point increases 3 degrees for each pound of pressure, so a 4 lb. system boils at 224 degrees, a 7# system boils at 233, etc. All the above temps represent the boiling point at sea level- - - - -coolant boils at lower temps as altitude increases.
Jerry

Thanks Jerry and great information, however, I still do not know why some gauges have the 'red warning line' on the temperature gauge and others do not.

Hi guys I just had a look at my temp gauge on my 42 1 1/2 ton truck and it has the hi temp red line, my truck was built in Detroit and it is a R/H drive truck for lend lease program here in Australia. good question Big Tee
Cheers Justin

Don't forget these trucks are over 70 years old. It's entirely possible if it was red that it would have faded away by now.