73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: Harmon on June 11, 2011, 11:45:56 pm
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When I turn my AC to the high setting it seems that there should be more air coming out. I have a 1986 c10 chevy and I bake on a 40 minute ride home because not very much cold air comes out of the vents.
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is an '86 air plenum controlled by vacuum or by cables? If vacuum, I'd look there. Perhaps vacuum reservoir or line isn't holding. If cable, perhaps some binding issues under dash. Blower motor going bad?
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Not quite understanding what the problem is. You say " it seems that there should be more air coming out. "
Then you say " because not very much cold air comes out of the vents. "
Is it the amount, or the temp. of air that you have a problem with?
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can you feel a difference when you change speed of the blower motor
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There is a difference when you change from low to high as far as speed. The air does blow cold as well.
The problem is it feels like more air should be blowing out of the vents.
My Dad who has a 77 Gmc pick up said, "It doesnt feel like there is much air blowing out of the vents." ===It was on Hi.
The air coming out is cold, but it feels like more should come out on Hi....
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I'd be looking for leaves blocking the air intake.
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There is a difference when you change from low to high as far as speed. The air does blow cold as well.
The problem is it feels like more air should be blowing out of the vents.
My Dad who has a 77 Gmc pick up said, "It doesnt feel like there is much air blowing out of the vents." ===It was on Hi.
The air coming out is cold, but it feels like more should come out on Hi....
Both my 82 and 90 Suburban are similar to what you describe. The fan just does not blow that much air. I'm not too surprised because Chevy has always been known for finding ways to save pennies. I wonder if there is an aftermarket fan that puts out a lot more output. Or possibly, maybe the electrical wire to the fan is undersized.
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Check all the duck work for holes
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If its the fan, replace it with a late model blower motor for even more flow.
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If its the fan, replace it with a late model blower motor for even more flow.
Good information here. Do you know how new of a blower motor to use? Could I use a blower motor out of a 2000 Chevy truck? I ask because the blower motor from my 1990 Suburban is just as weak as my 1982 Suburban
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Have you checked to see if any of your air is coming out under the dash on the floor? My A/C in my '84 blows cold, but when on "Hi', most of the air is actually coming out the floor vent. Ive never got a straight answer from anyone as to why its like this. Some people say check the blend door, some people say check the cables, some people just dont know, but its sucks!! I'd spend some decent $coin$ to have a good A/C in this truck.
***Id also like to know how late of a model blower motor we can use to maybe increase the air flow.
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If its the fan, replace it with a late model blower motor for even more flow.
Good information here. Do you know how new of a blower motor to use? Could I use a blower motor out of a 2000 Chevy truck? I ask because the blower motor from my 1990 Suburban is just as weak as my 1982 Suburban
I personally do not know. But a few other forum members have mentioned it and done it. Theyll probably fill us in when they see this post.
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Good info....thanks yall.
I have alot of air coming out on the floor vent as well.
It seems that even though it blows cold, I cannot cool my truck off enough in the texas sun to make driving the vehicle comfortable.
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Good info....thanks yall.
I have alot of air coming out on the floor vent as well.
It seems that even though it blows cold, I cannot cool my truck off enough in the texas sun to make driving the vehicle comfortable.
Sounds like you might need to add some more refrigerant. I refilled the A/C on my Suburban and it'll freeze you out of the vehicle even with the Texas heat.
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You shouldn't just add gas to the system. Each system is designed to take a certain weight of gas. To much it may blow cold, or it may not. But it will shorten the life of the components involved.
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You shouldn't just add gas to the system. Each system is designed to take a certain weight of gas. To much it may blow cold, or it may not. But it will shorten the life of the components involved.
Yes, best to be done by weight. It can also be done with pressure gauges but to a less degree of accuracy.
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Ive got 3 cans in the system..at 12 oz a can that is 36 oz which is what some people said to do on this website.
I live in Houston, and getting in my truck after work, I drive 20 miles....by the time I start driving I have to ditch the AC for both windows down or I start sweating.
It just seems that more air should be blowing out of vents.
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does it seam ok at first then get worse?
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Get a blower motor for a '94 Chevy truck. It works for the A/C trucks only, because there isn't enough depth to work on the non-A/C trucks. This motor has more windings and sounds like a hurricane on high-speed.
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^ yes. I use a 94 pickup motor and it works much better, but it sounds like you have a switching problem in the ductwork. Check for vacuum leaks and check the vacuum diaphragms for proper operation. A simple vacuum leak will prevent the gates from routing all of the cold air through your vents.
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I recently went through my heater box in my '77 because the core started leaking. I had a cracked and broken rubber hose that goes to the blend door vacuum pod and the internal foam seals were all shot! I had a similar feeling that it just didn't seem to control the airflow or put out much to the individual vents. Replacing the seal, fixing the vacuum leak and a new heater core made 100% difference! It still doesn't blow much velocity, but I can control where it goes and it does put out a little more volume.
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From what I have seen on the fourn here, the 94 blower motor pushes a lot more air than the stocker. I think Fitz is running this conversion. I am going to be doing the same shortly when I go through my system. I have no compressor on the truck right now and a hole in the heater core. Also the fan is pathetic, so it'll be almost a total system rebuild.
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Another bonus of the newer motor is that it comes with the plastic fan. My old one was brittle and missing some fins. The motor for my 82 was close to the same price but you have to re-use the old fan, and the one for the 94 came with a fancy new one.
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From what I have seen on the fourn here, the 94 blower motor pushes a lot more air than the stocker. I think Fitz is running this conversion. I am going to be doing the same shortly when I go through my system. I have no compressor on the truck right now and a hole in the heater core. Also the fan is pathetic, so it'll be almost a total system rebuild.
Thanks for the excellent information. I bet this might even prevent my A/C evaporator from freezing up. My A/C runs so cold that on a hot humid day, the evaporator freezes up and blocks the airflow and I have to turn the A/C off and let it warm back up every so often.
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I bet this might even prevent my A/C evaporator from freezing up. My A/C runs so cold that on a hot humid day, the evaporator freezes up and blocks the airflow and I have to turn the A/C off and let it warm back up every so often.
this is what i was getting to. even with the 94 fan you still will freeze up i bypassed a pressure switch on my 94 and it would freeze up no matter what temp or speed i was running the fan at
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Shouldn't the low pressure switch prevent it from freezing up, even with a marginal fan?
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On my '86 there were two doors that were controlled by vacuum and one door that was controlled by a cable. The problem was the one controlled by the cable--it was a plastic door on a metal rod and the plastic was worn such that the door was flopping back and forth.
I finally took the whole unit out of the truck, took it apart and just went through it. Made a tremendous difference. You can see this door if you partially disassemble while still in the truck--it is attached to the temperature control.
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The flex hose that goes to my passenger side vent fell off behind the dash last week. I had very little air coming out of the remaining vents though it was still just as cold as before. After pulling the glove box I saw the problem and used to duct tape to make sure it won't happen again.
While I was under there I found a seam between the two halves of the condenser box and air was leaking badly around that seam, so I taped that up too. Now the airflow is easily doubled, will part what little hair I have left when on high. :)
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Awesome...I have hope then...I am going to give a look into all this today!
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I posted this in another thread but was wondering if the fact that I do not have the vacuum canister thing behind the passenger kick panel plugged in then I am losing vacuum under the dash somwhere?
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Hook it up or plug the hose. It's for a vacuum diaphragm that opens a vent door.