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Discussion Starter · #1 ·
My car is blowing hot air out on an irregular schedule. When I first turn the car on and turn the top middle and bottom vents on (along with the AC button) the face vents blow decently cold air while the top and bottom vents blow warm air. As I start to drive and especially when I get on a parkway/highway (70+ mph) the top and bottom vents begin to blast extremely hot air and the face vents turn to luke warm. When I turn the top and bottom vents off to keep the hot air from coming out it just comes out of the face vents. I have added refrigerant recently and also replaced the blower resistor final stage unit. Any help is appreciated!!
 

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Mine does the same thing I just put it on the middle and bottom and keep the fan low and it barely blows hot out the bottom. From the research I did it's actually the heater valve getting stuck open. This valve is right under the airbox I guess you can take it apart and clean it I haven't bothered to try it yet.
 

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Discussion Starter · #7 ·
alright thanks alot guys. I took the air filter box out and took apart the heater valve and it was completely decayed and crumbling within. This has got to be the problem i was looking for. hopefully. Thank yall for your assistance and time!
 

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I guess that's what happens when you don't use a proper coolant or do not maintain the cooling system properly... I don't even want to know what else is flowing in that circuit, I suggest using some chemical coolant flush to dissolve the crust from other parts while you're at it... cause the next thing will be the thermostat or worse.
 

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Wise words.
The coolant has lubricant and preservatives added. That's why fresh coolant helps to make your hoses last longer. The hoses rot from the inside out, so you won't see the damage until it's too late. That's why a squeeze is the best way to see if hoses are firm, rather than a visual inspection.
The lube is good for the WP bearing. That's why a bit out the weephole once in a while hurts nothing.
 

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lol ya for some reason I thought he was talking about the hoses and not the actually vavle. I better check mine I hope it's not decaying I change everything but this vavle on my cooling system.
That is funny.
Usually heater control valve lasts real long. Especially is you take care of your coolant.
Our cars will get to the age where it isn't silly to replace it if you can see it!
My car gets such easy duty that every time I PM a part, the old one comes out looking like it wasn't even at the halfway point. So I save the old parts. Better that than being stranded 1600 miles away from home. Getting ready to drive cross country again next week.

The hard part about replacing some of these smaller hoses is they run back into the engine in not so easy to get to places. And connecting to those pipes might reveal a weakness you don't want to know about. Like the two composite pipes under the intake manifold.
 
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