thumping sound when heater/ ac turns on?

My car makes a thumbing sound when I turn on the heater/ air conditioner. If I press the max cold button, the thumping sound goes away. I checked the fan and there did not seem to be any obstructions. Is this a spring or something?

2003 Pontiac Vibe, 115,000 miles

2 Answers

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  • Anonymous
    1 decade ago
    Favorite Answer

    First check the a/c heater blend door for proper operation on fully closing and opening from a/c to heat.......

    Source(s): 316
  • sommer
    Lv 4
    4 years ago

    "Frozen Anti-Freeze? Are you specific?" In that Temp. in case you're working 60% anti-Freeze & 40% water, i've got under no circumstances heard of it Freezing at much less then fifty 5 under, Parked outdoors and blowing. Park it interior in case you may and/or conceal the warmth hood or engine with 2 heavy Blankets. The Thumbing mutually as warming up is "Air Trapped in the gadget". Drain & Fill with the 60%-40% blend, replace the thermostat & examine the Water Pump. Temp drop grow to be led to by using the Air in the gadget and would have led to an overheat you probably did no longer see on the gage.

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