I'm having a problem with the airflow on a/c. The blower is running fast but the flow is weak. I've just replaced the evaporator core...it's a little better but still weak. I did notice that the foam gasket on both sides of the blend air door had deteriorated to where it wouldn't seal between heater core and evaporator core so I replaced it with some door gasket material from a hardware store. The ac is very cold down to 35 degrees and I dont have a metal clang sound when I fully move the temperature lever back and forth anymore but the airflow is still weak and I noticed that the defroster and heater vents are having some airflow on the face vent setting also...I might have to remove the air distribution housing because I'm afraid the gaskets around those doors have deteriorated also..if I do how do I get the housing out or is there another way?

 

Was the air flow low prior to replacing the evaporator?

 

Yes..when the weather is hot and sunny the ac doesn't keep up...the vent air is cold but the airflow isn't sufficient at all...especially to back seat passengers

 

Not sure there is a blend door as such. The car has coolant valve on the heater core to vary coolant flow which varies heat.

Is the blower getting enough air? Have you tried changing from outside to recirculate, etc to change the air source?

 

Yes..I do notice though there isn't any change in the sound of the airflow like other cars have when its from outside air to recirculating air. The airflow remains the same I did check the recirculating/ fresh air door and it is moving when I slide the lever back and forth. And I could feel the air drawing into the blower housing from the opening under the dash when on recirculating air

 

The output air is either blocked or going someplace else other then the dash vents. Check if there are outlet vents under the seats.

Might drop the blower motor (easy job) in case there is a mouse nest inside or such which has happened.

 

ok I'll check thanks

 

I checked and had some foam in the vent system..I cleaned it out and now airflow is good. I put a thermometer in the vent but its reading 60 degrees sometimes 55...but not lower than that when it's hot and sunny outside. I clamped off the heater hose but it didn't change the temperature. I installed a set of gauges on it and the high side reads 200psi and low side 32psi at engine idle...about 245 and 25 at 1500 rpm. The compressor cycles even at the idle readings more on than off possibly due to the temperature sensor in the evaporator case. Is there anything that might cause the higher temperature? Both radiator and condenser fans are running. I've evacuated the system and filled it with 2 12oz cans of r134a and 3 oz of pag oil. System spec is 26oz.

 

For starters look for a glass window on the top of A/C dryer which allows for looking directly at the Freon in the system.

The site glass should be clear when the A/C compressor is off. When the compressor starts there should be bubbles in the glass that disappear. When the compressor turns off bubbles should appear then disappear.

If you see bubbles that don't disappear or no bubbles at start up/shut down there is a problem.

Other items to check:
-Condenser coils for obstructions to airflow.
-Expansion valve. With gauges installed operate engine at 2000 RPM for 5 minutes. If valve is clogged low pressure side will drop to zero.
-Check temp thermister. Should be 1500 ohm at 77F.

You might try to drill a hole in the climate system housing right after the evaporator, then install your temp gauge here. Or two holes, one before and one after the evaporator to obtain its temperature drop.

One more thing is make sure debris is not plugging the evaporator.

 

I drilled a hole on the output side of the evaporator case close to the evaporator core and slid a thermometer in...the temperature went to 35 degrees and then the evaporator temperature sensor kicked the compressor off. But the vent temperature was at 55 even with the heater hose clamped. If I jump the case temperature sensor the vent temperature will eventually get down to 40. The sight glass is clear and when the compressor kicks off a few bubbles appear then clear...when it kicks on the bubbles reappear but then its clear again. The only thing I'm worried about is evaporator core icing because of the circuit jumped but the vent air gets down to around 39 and doesn't go any lower. Don't know whether I should leave it or pinpoint the exact problem..It seems something is wrong in the air distribution box that's causing the temperature problem. I bought a crimper tool made to crimp off heater hoses so I'm pretty sure there's no flow through the heater core and I felt where the heater core is located and it's not warm at all. I just replaced the evaporator core and expansion valve last week. The receiver dryer about a month ago.