[John2kx]

RM,

I've tried no less than 5 different water gages on my car and found differences in the way mechanical vs. electric work. Same goes for the cheap vs. higher priced electric gages.

This is what I have observed:

Cheap ($20) gage I purchased at my FLAPS electric read pretty close to 180F all the time once engine was up to operating temp. I used this one until my my recalibrated VDO came in from North Hollywood.

The high dollar VDO read higher than the $20 unit in similar conditions and did seem to change according to heat load produced by engine. Testing of the cheap gage in water with infared showed calibration to be off at 180 and very slow to respond as temperature was increased or decreased around 180F. That one was added to paper weight collection. I don't see any change in my electric VDO gage as accessories are turned on to include lights, radio, radiator fans and a/c. I'm running a 100 amp GM alternator and ALL grounds in electrical system very checked/cleaned during assembly of car.

A mechanical Auto Meter was added as a backup and found to show temperature changes immediately as compared to any electric gage I have used. The fast response is a little scarey to watch until you get used to it. I find this one to be the one I trust more so than any other measuring device on my car.

Veryifying calibration is a must but I'm in the air about response time between mechanical and electric gages.

John