I have a '76 country squire and the A/C system is stock. The air flow out of the vents is really poor. I would imagine that getting a bigger blower would increase the airflow. Any recommendations for specific after market replacement blowers that will double or triple my air flow at max setting?
I worked in an a/c shop for seven years, and this question came up a lot. Short of going with something aftermarket under the dash, there is really no way to add a larger fan to a stock system. The factory designes the largest fans possible to fit in the case. Keep in mind the stock system is a maze of hoses and lines, and also blows through the a/c evaporator and heater core, so your #1 job should be seeing if you have leaks or blockages in the system. This is a common gripe/issue on old cars. Pull the fan and make sure when you put power too it, that it's spinning as fast as it should. Motors can wear out over time, and also make sure the blades are clean and not damaged. On some cars they used plastic squirrel-cage fans and those can crack and break over time. I also bet the evaporator is all clogged up with dust and debris from years of use. If you can open the case get to it, try to blow it out with air or use a vaccum or soft-bristle brush...just be careful, they're fragile. When you put the case back together seal it up with some tar-tape. The heater core can also get dirty with age, but the evaporator, which is contantly wet when the a/c is on, attracts dust like a sponge and over time can get BADLY restricted with dust/grime/muck in it's fins. Lastly check your vents. If you have paper-based vent hoses in the dash, they may be torn or leaking, and even if they are hard plastic, they may be leaking at joints and such. Finally, when the a/c is fully on, make sure the air is only coming out the dash vents, and not also coming out the defrost or floor vents too. If your blend door is not working correctly that can cause this and you will have very weak air pressure out of you vents. Vent door are normally controlled by vaccum so check for loose or broken rubber hoses and listen for hissing under the dash. Good luck! -Mike
thanks! You are the man! Will check into all those things. I understand most of what you are talking about there, since i design chemical scrubbers, biofilters, and carbon adsorbers for a living. I'll have the dash apart this winter as i go to customize several features in this car and i will track the ducting and vacuum lines on that 'side' of the car. The under-the-hood stuff may be a bit trickier for me and I'll let that go until spring. Georgia summers can get pretty hot. The AC itself works fine, just very low air flow to cool a very large volume of cabin air...
The only part of that system that is under the hood is the heater core. The rest is all in the dash. Do you have the ordinary A/C or the climate control system? The climate control system uses vacuum to adjust the temperature, and it is a pain in the neck! You should find that when all the duct work is clean that you have plenty of air flow out of the dash vents. These old Fords used a 'squirrel cage' fan, and they do tend to move a LOT of air. Enough that with all 4 dash vents open, you find your hair ruffled in the breeze.
This is standard -- not climate control. Should be pretty straightforward. Appreciate the tips. Now if only someone could help me figure out which universal weatherstripping will work best for my doors, windows, and tailgate -- i'd be in business.
