Why does my fan motor blow with less pressure when on heat vs cold?

2003 CHEVROLET IMPALA
186,000 MILES
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BAHO_15
  • MEMBER
  • 1 POST
At first I was getting very little heat from the car. I changed thermostat, radiator cap and added more coolant. Now I get heat, but it is very little pressure even on high. If I simply lower the temperature setting to cold it blows much faster and stronger. When on high heat and vent, it sounds like it should be blowing much more than it is. With most of that noise coming from the dash (even though I have it on vent and nothing is blowing out of dash).
Dec 2, 2011 at 3:34 AM
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JACOBANDNICKOLAS
  • ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
Check HVAC vent doors for operation. Check to make sure the fresh air vent is working properly. Also, make sure the heater core box isn't contaminated with leaves, dirt...
Dec 2, 2011 at 3:37 AM
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