Random loud popping & heat issues 2003 Buick Rendezvous

I’m buying this car from a good friend, but it has a couple strange issues…not sure if they’re related? The heat works great on the drivers side but blows cold on the passenger side. There is a loud popping sound that comes around every once in a while (no real rhyme or reason) sometimes before you even start driving. I’ve attached a video below so you can hear for yourself. Thanks for any help! Here’s a link to the video of the popping: https://imgur.com/gallery/58EY52N

First guess broken blend door or actuator.


The absolute best way to ruin a friendship is to buy from or sell to a friend.


Agree with Barky. It sounds like the actuator that opens and closes the blend door is overextending. The popping sound is probably the little plastic gears skipping a cog and begging for mercy. I think you can hear the actuator hum before you hear the “pop”. The door is probably in the fully open or closed position, and the actuator is still trying to move the door. Sometimes the actuators can be reset by pulling the battery cables.

As a test, if the temp is set all the way to cold or all the way to hot, change the temp setting and see if the popping stops or changes at all.

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Haha except that it’s a stupid good deal and she could care less about the car. But yeah $ and friwnds is usually a death sentence lol

Thank you for this! Will definitely look into it.

But it’s such an ugly car. Why would you want a 16 yr old car with a poor history of intake leaks and bad headgaskets? Is coolant level ok?