95 Astro engine temp reads low

[Paul09876]

Hi, my 95 Astro temp gauge reads about 160 under most operating conditions. I just pulled the thermostat and boiled it in water, opening at the correct 195 degrees. To check to make sure the temp sensor was working I drained some coolant and ran it until the gauge went all the way to the red zone. Still may be the sensor, don't have a ohm/temp chart to check it. Before I buy a new one could it be something else-gauge/wiring? The sensor only has one wire, was it later they went to the 5v reference sensor? Is the low gauge reading making it run rich? Thanks!

[ericn1300]

Originally Posted by Paul09876

To check to make sure the temp sensor was working I drained some coolant and ran it until the gauge went all the way to the red zone.

Ouch, that was kinda severe since a sender is under $10. replace the thermostat, temp sender and radiator cap all at once, probably around $25 total,and at that age they all need replacing any way, and see what happens. my bet is the rad cap isn't holding pressure anymore.

[old_master]

Your 95 Astro has 2 temp sensors: one for the computer, (intake manifold near the thermostat) and one for the gauge, (left cylinder head between plugs 3 & 5). I believe 98 was the first year that only one sensor was used for both PCM and gauge. Class 2 communications are used to send data to the temp gauge in the dash. If the engine is in fact running cold, the PCM will richen the fuel mixture and cause a drop in fuel mileage. Eric's suggestion will most likely take care of the problem.