pvdh286

While driving on a long trip my temp gauge all of a sudden went all the way down, I had very little heat blowing, then after 80 miles or so, the gauge went back to normal where it goes up and down-- as the fan kicks in and out. Could this be a sign the thermostat is taking a crap? thanks Pete 1995--cummins auto, 200,000 miles

dssimecek

Tstat would be a good bet. Prolly time for a clean, flush and refill the cooling system. How cold is it outside when the themp drops way down? Stop and get out and feel the outlet on the head or read the tempature with an infared tempature checker. At normal temp the outlet reads 180*F with the IR temp checker. It is a handy thing in the truck about $50.00