Original temp. sending unit? I'm not sure if there is a difference from '70-'83.

 

step #1, find out what the real temp in the engine is.
there are several posts in archives about using a dial thromometer in the coolant.

 

hey me too , iam like that!

 

1/4....1/2...."On 'P' of Temp"

The stock gauge is useless unless you first determine where your temperature is with a real gauge!

 

1/4 like right by the 120... i think that's what you mean tony

 

I just rebuilt my engine and replaced the thermostat, housing, and temp sensor. Now it runs nice and cool. Which I think is a good thing?

 

Nope...

What I meant was:

"My Engine runs 1/4 on the temp gauge: How hot is my engine?"

"My Engine runs 1/2 on the temp gauge: How hot is my engine?"

"My Engine runs On 'P' of Temp on the temp gauge: How hot is my engine?"

The answer IN EVERY CASE above was "185 degrees +/- 5" when measured with an Infra Red Temperature gun at the upper radiator hose dump into the radiator, and then rechecked with a thermocouple installed in the coolant flow of the upper radiator hose while running.

Three cars, three different gauge readings, EXACT SAME TEMPERATURE IN EACH CASE.

What I am trying to tell you is (and let me be a bit more precise and punctuate a bit better) THE STOCK GUAGE IS USELESS WHEN TRYING TO DETERMINE WHAT TEMPREATURE AN EARLY Z-CAR IS OPERATING!!!!!!!!!!!!.

Are we clear now? Check it with a REAL gauge. Chances are you do not have a problem, it is an issue of "gauge drift".

First step in all troubleshooting (fault finding for our friends who speak the Queen's English) IS TO VERIFY the units instrumentation before proceeding further. Takes but a second, saves foolish expenditures later!

My .02: it's reading low.