2000 Pontiac Montana Heater only works at high rpms

2000 PONTIAC MONTANA
170,000 MILES • 6 CYL • FWD • AUTOMATIC
Avatar
JRING94
  • MEMBER
  • 6 POSTS
At idle the heater blows cold. Go down the road or just raise the rpms and the heater blows warm. Does anyone know what the little pump is for that is in line with the heater hoses and when it should be on??
Oct 19, 2010 at 8:39 PM
Advertisement
Avatar
SERVICE WRITER
  • CAR REPAIR CONTRIBUTOR
  • 9,123 POSTS
Post a pic regarding the pump

Check your antifreeze level, sounds like it is low or there is a restriction in the heater core.

If the fluid is low is will not circulate into the heater core until the water pump spins faster from the raised rpm..
Oct 20, 2010 at 7:49 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.