intermittent

2000 DODGE TRUCK
1,200 MILES • 6 CYL • 2WD • MANUAL
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SOCCER14
  • MEMBER
  • 2 POSTS
My truck heats up to 250 degrees with no heat coming into the cap then cools down to 150 and then I get heat ,then rises up to 210 degrees then no heat, then climbs up to 250 degrees then it cools off and I get heat again,and I also changed the thermostat. Please give me help and advice.
Dec 9, 2010 at 6:02 PM
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CARADIODOC
  • CERTIFIED EXPERT
  • 34,308 POSTS
Check the thermostats for a tiny bleed hole with a weight dangling in it. If there is none, drill a 1/16" hole in it. When it is totally closed, it takes a while for the heat to get to the sensing element in the bottom of the thermostat. While waiting for that to happen, the gauge sending unit is already registering an increase in temperature because it is closer to the source of the heat. Once the thermostat finally opens and coolant circulates into the heater core, the cold coolant comes rushing in from the radiator and the thermostat closes again. Given enough time this will even out, but that little bleed hole will let just enough coolant sneak through to warm the thermostat and cause it to open sooner.

caradiodoc
Dec 9, 2010 at 6:24 PM