Calibrate temp gauge/sender? - Third Generation F-Body Message Boards

Crazymidget01 · 09-22-2009, 11:16 AM

I installed a gauge cluster that I purchased off of ebay into my 1985 Camaro 2.8L. I believe it was a z28 cluster with the dual speedometer needle with mph and kph opposite each other. Anyway all the gauges worked except the coolant temp and oil pressure. I started by fixing a broken ground on the cluster, and then installing a new temperature sending unit. The gauge now works, but when I reach operating temperature it reads in the red, and I know my engine is not overheating. Is there a different resistance that I can compensate for in the cluster to calibrate the gauge to read properly. I plan on changing the oil pressure sending unit soon also...hopefully I won't have this problem with that. Thanks for any help...

Joe

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NINÅ · 09-22-2009, 03:01 PM

You didn’t state if it’s accurate on the cold end of the scale.

That could change the answer.

Anyway you can put a resistor in series with the gage.

Use a 2KΩ rheostat and put the knob in the center.

Get your water temp up to 160°.

Adjust the rheostat to read 160°.

You can disconnect your fan to Get your water temp up to 240°.

See if your gage reads 240°.

Compare the readings to a test instrument gage to make sure your newly calibrated gage is giving you reliable info.

Happy Racing!

If People Drove Any Slower They’d Be Going Backwards

Fog lights are not driving lights. They look dorky. Turn em off slow pokes.

How bout those dorks too scared to drive without headlights on in the daytime or if there is a little rain!

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Crazymidget01 · 09-22-2009, 06:08 PM

I'm actually not sure if the cold end is accurate, what is the easiest way of testing the actual water temperature?

NINÅ · 09-23-2009, 11:56 AM

Immerse the sender (except the electrical connections) in a vessel of water maintained at 100° monitored VIA a known good thermometer.

Now you can calibrate the low end of the gage.

Happy Racing!

If People Drove Any Slower They’d Be Going Backwards

Fog lights are not driving lights. They look dorky. Turn em off slow pokes.

How bout those dorks too scared to drive without headlights on in the daytime or if there is a little rain!

.
.

Mike M · 10-08-2009, 07:50 PM

Using a Rheostat or even a resistor in line with the sender will only let the gauge read accurately at one temperature once it is calibrated properly. The gauge is "calibrated" for use with the sender used on the vehicle from which it came and THAT is your fix. Contrary to popular belief the gauge CANNOT be recalibrated. It is designed to work within a specific resistance range which corresponds to the proper temps.