dennisr

I've needed to address this problem for a while know. My 81 blows both hot are for the heat and cold for the AC. The problem is the volume of air is very weak. All four fan speeds seem to work ok, not just not strong enough. Any sugestions on where to start? I know the car should heat and cool better as I have a friend with an 80 and his fan blows much harder than mine.

Thanks,

Alwyn678

U probably have leaky duct work of a bad fan motor that is not producing the correct volume.....I pulle my dash out and resealed my air ducts and that helped a tremendous amount with the volume

81vette

Could also be the leaves, etc. that accumulate in the AC/Heater box over the years. Mine was 50% blocked when I tore it out.

john's '81 mouse

You already have the answers above:

1) Bad / no seals on duct work in and under dash.

2) Weak blower motor and or dirt build up on fan blades.

3) Lots of crud/leaves etc. in evaporator box. When I replaced my blower motor, I used my hand, vacuum cleaner and air hose to clean this area out, and got lots of stuff out of there. You should have black plastic screens at both ends of your cowel area, and the one on the passenger side is supposed to help prevent this junk from getting in there, but you'll see that they dont' fit too good even if you still have them attached. I took the passenger side screen off, and attached some aluminum door screen to the back side, of the plastic screen using small wire, and I cut the aluminum screen to fit the gaps left by the OEM plastic screen, then painted the entire assembly semi-flat black and re-installed. You really don't notice my modification unless you look closely, and it fills this gap much better than the OEM screen on it's own.

ScubaJKD

My vette had sat for years and I had the same problem. Only difference was that a family of mice had created a very nice nest in my heater box and chewed up the duct work. Small block suffers RAT attack :lol:

dennisr

Thanks for the reply's everyone. I was kind of hoping I wouldnt have to pull the blower motor but I guess I will. Sounds like a good project for this weekend.

Thanks again,
Dennis

Strike3

By the way Dennis, In a book called "Air Conditioning Strategies for 68 to 82 Corvettes", the author recommends the use of a 1984 fan rotor blade in place of the earlier original style. He claims that the later fan is the same diameter but has more blades and at a steeper angle all increasing air flow. I'v found that there are two 84 fans, one a press on, the other is held on by screw. I am in the process of trying to buy one and after looking at mine (1980), I think the one that is held on by screw or nut would probably be the correct one and sales for about $18.00.
I'm taking my box & ducts all apart and having the heater core cleaned and checked at my local radiator man. I'll be cleaning the A/C evaporater myself and reassembeling the whole thing with new seals and putty. I'm also checking out all the damper actuators and putting in a new vacuum hose kit. I've rebuilt the A/C heater controls on my consule so the system should be better than new when I finish.
Good luck!!


[Modified by Strike3, 1:46 PM 12/7/2001]

Dalannex

John's 81 mouse said it all again. :) Your blower will work just fine once you tear it all apart and clean up the heater core, evaporator, fan, ducts, and heater box. Taking the fan out won't clean it well enough to get adequate flow. You really need to do a complete heater box rebuild. It's a big job, but I think it's the only way to get it to work correctly again. A higher volume fan won't do any good if the heater box is restricting the air.

shawn_cake

In addition to all the other recommendations, ensure that the GROUND wire form the fan makes a GOOD connection to FRAME GROUND.