AC Blower

[minifridge1138]

Hey everyone,

My AC has been "upgraded" to 134A. There are no leaks, and the air comes out cold. But there isn't very much air. My fan works correctly (all 4 speed settings work) but the highest setting just isn't very powerful.

Is there any way to improve the amount of air that the fan blows? (blower from a newer car perhaps?) Just wondering if anyone has any experience with this.

Thanks!

 

[SIXFOOTER]

you can put in a C4 blower and it will move some more air, it will require fabbing a 1" spacer since the C4 fan is 1" longer. However, there are other things to do first. Remove the blower and see if the bearings are dry and tight, little lube will help with that. There is likely a quantity of mouse fur, dirt, leaves etc in the evap box on the evaporator, use a shop vac hose to get in there to get as much out as you can. Also make sure all the ducts under the dash are fot together correctly. There was a little strip of foam seal between the ducts that has probably dies some time ago. There is a gap between the center dash duct and the lower box, for some reason the General didn't see fit to fit them together!

 

[MikeMc71]

I agree with Sixfooter......I pulled a gob of 30+ year old residue out of my '71...the blower blows like a champ now! In fact the thing was frozen up, with a little lube and coaxing...I got it running again!!

 

[minifridge1138]

Thanks for the advice. I have another question, how hard is it to get to the blower motor? Is it behind the dashboard or in the engine compartment?
Thanks!

 

[wishuwerehere82]

You will be coming up from underneath the fender well and reaching up real far.
Sometimes it's better to go by feel than trying to see what you are looking for.

 

[SIXFOOTER]

There are 5 1/4 drive screws, a socket, 6" extention and rachet will get it, you can get a couple from on top and couple from the bottom, not all that hard.

 

[RMS73]

I installed a motor and fan for a 78 in my 73 last fall. It made a big difference and no alterations, ie spacer, was needed.

Used a PM105 motor from AutoZone - it is for a 1978 Corvette. I had to make a difference vent tube since this motor had a small hole for the vent tube to fit into. Went to the junkyard and got two and cut to fit.
Install a wheel for the 78 Corvette also. It came from Advance Auto P/N 35603. The wheel is metal and about a 1/8" too narrow, but it fit and moves much more air. I am checking with ZIP Product for a plastic wheel. They were out of stock last weekend.

With this combination installed I can feel air in my face while driving with the controls in the A/C- normal position. It is not enough to blow my hair, but much better than before. Before I had to hold my hand no further than 6" from the center ducts.

Also made certain the contacts were clean and the high speed relay was working.

Using this combination the wheel speed increased from 2920 rpm to 3358 rpm with just the battery voltage applied - the units were tested on the work bench not in the car. When installed the new unit ran at 2631 rpm with battery voltage of 12.1. With the car running and an alternator output of 14 amps the motor turned at 3318 rpm with the controls in the normal A/C position and 3691 rpm in the vent position.

Roger