Heat blows cold air after ten seconds?

Tiny
JESSIE HUHTA
  • MEMBER
  • 2002 JEEP LIBERTY
  • 3.7L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 175,000 MILES
My heat when turned on will blow warm for a few seconds then turns cold. Replaced radiator, water pump, serpentine belt, all new hoses, flushed heater core, and replaced blower motor actuator resistor. Please help Upper Michigan is really cold this time of year! Thank you
Monday, December 19th, 2022 AT 9:42 AM

1 Reply

Tiny
STEVE W.
  • MECHANIC
  • 15,237 POSTS
Most common reason for that would be a thermostat that is stuck open and doesn't let the coolant get hot. It's a known issue with the modern Chrysler, Jeep, Dodge vehicles.
On the 3.7, the thermostat housing is down at the bottom of the engine block on the front. To replace it, you first drain the coolant. Then remove the two bolts that secure the housing to the cover. Then you clean the surfaces off and swap the thermostat. Make sure the bleed hole is installed with it to the top.
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Monday, December 19th, 2022 AT 10:21 AM

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