I just got my air conditioning fixed on my 71 cutlass s. The air is cold and the fan works on all speeds but it seems like it is not blowing enough air into the cabin of the car. I do notice that there is a little cold air blowing at my feet but wonder if that is supposed to happen when i have high ac selected. The fan motor sounds like it is moving at the right speed. Do fan motors wear down and slow down?

Thanks

 

Just an idea but maybe some of the ducting and flexible tubes are not properly sealed? I wonder if any knows what the CFM @ each vent is?

Pat

 

Another possibility is dirt on the evaporator preventing the air from blowing through it.

 

i did a quick check and nothing (air wise) around the duct work is blowing through as if it was nt sealed. it doesnt appear that anyone has ever touched the ducts. As far as the evaporator, i am assuming that sits infront of the fan, correct?

thanks for your replies

 

The evaporator is to the air conditioner,,,,what the heater core is to the heater. All air, no matter if it is heated or cooled, must pass through both. I have seen more than a few evaporators develop a tiny leak, which allows a tiny bit of oil to leak, which catches all the dust that goes by it, and make a big muddy spot through which no air can pass, so no circulation, which is what you described in the OP. That doesn't mean this IS the problem, just that it is one thing I have ran into. Something is stopping the air flow, maybe someone else will have more ideas. But ultimately I suspect the only way to find the problem is to tear it apart and find it and fix it. You'll know for sure what it is when you see it .
If you do find a big muddy spot on the evap core it needs replaced, can't be fixed.

Good luck,
Mike

 

Even a non-leaking core can dirty up over time. Condensation (water) on the core during normal operation can cause dirt to stick to it. Also, it is like a coarse air filter, trapping tree debris, hair, lint, deteriorated underdash insulation...

You can pull the ambient temperature switch or the resistor fromt he evap box, and with an inspection mirror and flashlight, lake a look inside.

A small amount of air from below would be expected, as the foam seals are likely deteriorated and gone. The good thing is that this cool air stays in the car, so no real worries.

In my heater box resto adventure I found the inner heater box has a bottle neck at the mode door that prevents a good flow of air through the dash vents. I could not find an easy way to modify this. The heater vents get a large flow.

When I restored the Evap box, I found that the box easily leaks around the fan as there are not enough bolts to hold it tight. I sealed that area with extra strip caulk when it was installed. One layer will not do it.

The next time Lady is out, I will try to develop an easy test for dash vent air flow. She has a new evap and everything was resealed the best I could get.

 

Just a guess, but maybe the vacuum operated flapper in the heater box has issues and not sending all the cold air to the dash ducts. Is the cold air at your feet coming out of the heater duct? Anything out of the defrost ducts? Chassis manual has diagrams and color coding for the vac lines.

 

thanks guys, i will take a look and let you know. thanks for the suggestions.

 

so a week after i get the remanufactured ac compressor, and other new parts of the ac installed, the clutch on the compressor starts to freeze up and smoke. i am awaiting another replacement remanufactured compressor from the parts store. the shop told me they would only charge me 100 bucks to replace, still 100 bucks lost. i did check under the dash with the fan running and when i select max ac the little door behind the passenger side foot well panel does do its thing and opens up. one thing i noticed was that some of the major ducts under the dash had what appeared to be factory installed holes about the size of a penny, i am assuming to cool the feet area. the mechanic did say they will use a camera to check out the evaporator once the part comes in. Again, thanks everyone for your responses.

 

Check all of the blower wiring and connectors also for burning, pitting, etc. If they are getting resistive, you will not get enough voltage to the motor and hot connections can lead to a fire.
Check at the fan switch, resistor, high speed relay, fuse holder under the hood, and all the wiring in between.