AC does not blow much air on High

[Edahall]

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.

[Harmon]

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.

[Irish_Alley]

does it seam ok at first then get worse?

[ehjorten]

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.

[Grim 82]

^ 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.

[ehjorten]

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.

[slammed79]

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.

[Grim 82]

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.

[Edahall]

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.

[Irish_Alley]

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

[jaredts]

Shouldn't the low pressure switch prevent it from freezing up, even with a marginal fan?

[DrDaryl]

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.

[rainman15]

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. 

[Harmon]

Awesome...I have hope then...I am going to give a look into all this today!

[Harmon]

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?