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HVAC Question: Defrost is wierd..


1990lumina

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Hey guys and gals!!

 

Last winter I noticed the defrost on my 1990 Lumina is acting wierd..

 

Symptoms: When I have the blower cranked and the HVAC control set to Defrost and the temperature slider set to HOT, I get very little air blowing out of the defrost on the dash...

Now, if I slide the temperature slider to the COLD position, I get tons of air blowing out the defrost, but of course, it's fucking cold air and I don't want that!!

 

So is there something plugged in my HVAC system somewhere, or does something need to be flushed?? Dave's (C-BAD) thread reminded me about this issue, so I thought I'd ask and get it fixed before winter.

I don't know if it's a vacuum problem because my cruise control works fine, and when I have the HVAC set to blow out the vents, it does so, and when I click defrost, all the air is coming out the dash vent...so it is directing the air properly...just seems like it's plugged when in the Hot position...

 

any experiences with such an issue?? If I can't resolve it it'll go to a shop for this because driving around with a fogged up windshield is bullshit and isn't very safe either..

 

 

Another problem I have is when it's cold outside I don't have much heat...it's enough to take the chill off, but the heat just isn't very good compared to EVERY other car i've been in. However, right now the heat works amazing because it's warm outside. I don't know if it's because the engnine is running to cold in winter and it's not getting warm enough to warm the coolant through the heater core or what.....maybe the two problems are related?? Anyway if I get this issue resolved it'll be one check mark off my list of things to fix/replace before winter

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the air volume may be affected by a clogged heater core. how does the heat and flow volume work on vent or lower vent setting?

 

first, change your thermostat, it's cheap and simple on the 3.1

see if that gives you better heat.

 

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the air volume may be affected by a clogged heater core. how does the heat and flow volume work on vent or lower vent setting?

 

first, change your thermostat, it's cheap and simple on the 3.1

see if that gives you better heat.

 

 

thermostat is a 195*F IIIRC....but I guess it won't hur to check to make sure it's functioning correctly...

 

While in the Vent position, I believe the aur volume is the same no matter what temperature setting the HVAC is set to....I'll double check that today though

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