What causes Pontiac Montana temp gage stays at 160 while driving in winter Will move higher if ideling. Happens when the temperature is 30 or below. Causes the heater to not work properly.?

Answer 1

it sounds like your thermostat is stuck in the open position of possibly it has dissolved altogether, this is where i would start to look. or your radiator fluid is low had the same thing on my Montana, one way to tell if your thermostat is stuck open is to take the cap off the radiator only on a engine that is cool check to see if you can see fluid if not put a little water i till its up by filler neck then start engine up with cap off let it get warm if the fluid drop suddenly then the thermostat just opened up which means its prolly working fine, shut the car off fill the radiator up rest of way replace cap check radiator overflow make sure fluid is over the suction hose start car and run till warm should put allittle back in overflow and take allittle out