1979 l-82 ac
Thread Starter
Racer
Joined: Sep 2013
Posts: 254
Likes: 0
From: Charleston SC
1979 l-82 ac
I changed over my Ac yesterday and it blows cold air, but when i turn on the AC i get very little air at all coming out of the vents...
blower motor runs on all levels and you can hear it....i checked to make sure it was blocked
any one have any thoughts on this?
blower motor runs on all levels and you can hear it....i checked to make sure it was blocked
any one have any thoughts on this?
Instructor
Joined: Apr 2006
Posts: 108
Likes: 22
From: Duvall WA
C3 A/C Information:
Hello bbboy06,
C3 Air-Conditioning has a few questionable designs --->
1. The evaporator / under-dash plenum (box & ducts) have a bit larger volume (space) than needed.
2. The under dash board plenum & duct-work have several connections that are sealed with FOAM SEALS if these seals leak, you will have low to no air flow at your A/C dashboard outlets.
No matter how well your car has been preserved or stored, these seals are probably dust by now.
3. Even if your evaporator & duct work are in factory NEW condition the "VELOICITY" of the air flow (at any fan-speed) was weak when compaired to othe models of cars (IE: Camaro with A/C) thus the reason that some C3's have been up-graded to a LARGER C4 electric fan-wheel. The larger fan requires adding a 1-inch spacer between Heater - A/C box and the electric fan, located far right side engine compartment.
Start with sealing the system under the dash-board -
easier on a 1978-82 but still not a pleasant job.
C3 Air-Conditioning has a few questionable designs --->
1. The evaporator / under-dash plenum (box & ducts) have a bit larger volume (space) than needed.
2. The under dash board plenum & duct-work have several connections that are sealed with FOAM SEALS if these seals leak, you will have low to no air flow at your A/C dashboard outlets.
No matter how well your car has been preserved or stored, these seals are probably dust by now.
3. Even if your evaporator & duct work are in factory NEW condition the "VELOICITY" of the air flow (at any fan-speed) was weak when compaired to othe models of cars (IE: Camaro with A/C) thus the reason that some C3's have been up-graded to a LARGER C4 electric fan-wheel. The larger fan requires adding a 1-inch spacer between Heater - A/C box and the electric fan, located far right side engine compartment.
Start with sealing the system under the dash-board -
easier on a 1978-82 but still not a pleasant job.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
One of the major problems is also the white plastic connection on the main door that can break and not allow the correct movement. This can ONLY be identified with the main duct removed off of the heater box...OR possibly using a bore scope and going into the duct to see if it is still correctly attached.
AS for using the larger motor ( which I have done). I do not actually know if this truly helps due to the space is only backing out the motor so it will work...and the spacer is in an area where it is not providing any more air to be circulated....because it is outside of the area for are to be circulated. I have a very sensitive air flow gauge that I am going to test a car I am working on with all new A/C components and ducts sealed so I know what "brand new" would be in regards to air flow.
I have encountered that the leading face of the evaporator core can be seriously plugged up with debris which effects air flow considerably. I worked on a 1987 with a bad evaporator core that was 75% covered due to oil leaking from it...and I tested the air flow before it was replaced...and when the new evaporator core was installed...the air flow was considerably increased...so I know what a C4 should be if "like new"...in regards to air flow.
I do not know if I have the time to make a spacer and test the C4 motor on this car I am working on so I can actually see if it is beneficial or not. I wish I could stretch out time...at times. I really need to...but just do not seem to have the time for this test...maybe I can do it...just do not know.
As mentioned above...the duct seals do make a big difference.
You can remove the blower motor and go inside the hole with a bore scope and see how much is plugged up. YES...it is a pain...but sometimes it takes what it takes to find out a problem. Nothing is easy on these cars at times.
DUB
AS for using the larger motor ( which I have done). I do not actually know if this truly helps due to the space is only backing out the motor so it will work...and the spacer is in an area where it is not providing any more air to be circulated....because it is outside of the area for are to be circulated. I have a very sensitive air flow gauge that I am going to test a car I am working on with all new A/C components and ducts sealed so I know what "brand new" would be in regards to air flow.
I have encountered that the leading face of the evaporator core can be seriously plugged up with debris which effects air flow considerably. I worked on a 1987 with a bad evaporator core that was 75% covered due to oil leaking from it...and I tested the air flow before it was replaced...and when the new evaporator core was installed...the air flow was considerably increased...so I know what a C4 should be if "like new"...in regards to air flow.
I do not know if I have the time to make a spacer and test the C4 motor on this car I am working on so I can actually see if it is beneficial or not. I wish I could stretch out time...at times. I really need to...but just do not seem to have the time for this test...maybe I can do it...just do not know.
As mentioned above...the duct seals do make a big difference.
You can remove the blower motor and go inside the hole with a bore scope and see how much is plugged up. YES...it is a pain...but sometimes it takes what it takes to find out a problem. Nothing is easy on these cars at times.
DUB
