C3 AC blower
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Make sure your high speed circuit is working correctly, as it is on its own wire/fuse/relay.
This being said, it still will blow nothing like a modern car.
Pro
Joined: Oct 2009
Posts: 664
Likes: 89
From: Marysville Ohio
The c4 blower and spacer can help - the fan on the C4 blower is larger (longer, which is why you may need the spacer), and many think that is the difference.
I replaced mine and kept the stock 79 fan cage, and found that was much better. I suspect the C3 blower motors could move pretty decent air when new - but age does take a toll, in my opinion.
However - As AJROTM said, before you go to the trouble of R&Ring the motor, make sure you have a good ground connection on the blower motor with no corrosion, and that the high speed circuit is good - that may be a cheap fix and is at least worth checking.
My experience with weak air flow on my 79, just for reference - On my 79, I started with the ground, and that helped - but not enough to satisfy me. I found a replacing the 37 year old blower motor helped the most. I kept the stock fan and saw a noticeable difference in the motor alone. Keeping the stock fan allowed me to replace the motor without fabricating a spacer.
To get a blower motor, I went to autozone and bought a blower from a later 80s C4 (88 I think), then swapped fan cages after removing the old motor. The flange is slightly different, but close enough it bolts back up with no real problems.
I replaced mine and kept the stock 79 fan cage, and found that was much better. I suspect the C3 blower motors could move pretty decent air when new - but age does take a toll, in my opinion.
However - As AJROTM said, before you go to the trouble of R&Ring the motor, make sure you have a good ground connection on the blower motor with no corrosion, and that the high speed circuit is good - that may be a cheap fix and is at least worth checking.
My experience with weak air flow on my 79, just for reference - On my 79, I started with the ground, and that helped - but not enough to satisfy me. I found a replacing the 37 year old blower motor helped the most. I kept the stock fan and saw a noticeable difference in the motor alone. Keeping the stock fan allowed me to replace the motor without fabricating a spacer.
To get a blower motor, I went to autozone and bought a blower from a later 80s C4 (88 I think), then swapped fan cages after removing the old motor. The flange is slightly different, but close enough it bolts back up with no real problems.
Last edited by cooper9811; Jul 15, 2016 at 06:54 AM.
Le Mans Master
Joined: Jul 2000
Posts: 6,664
Likes: 162
From: columbia city in
The c4 blower and spacer can help - the fan on the C4 blower is larger (longer, which is why you may need the spacer), and many think that is the difference.
I replaced mine and kept the stock 79 fan cage, and found that was much better. I suspect the C3 blower motors could move pretty decent air when new - but age does take a toll, in my opinion.
However - As AJROTM said, before you go to the trouble of R&Ring the motor, make sure you have a good ground connection on the blower motor with no corrosion, and that the high speed circuit is good - that may be a cheap fix and is at least worth checking.
My experience with weak air flow on my 79, just for reference - On my 79, I started with the ground, and that helped - but not enough to satisfy me. I found a replacing the 37 year old blower motor helped the most. I kept the stock fan and saw a noticeable difference in the motor alone. Keeping the stock fan allowed me to replace the motor without fabricating a spacer.
To get a blower motor, I went to autozone and bought a blower from a later 80s C4 (88 I think), then swapped fan cages after removing the old motor. The flange is slightly different, but close enough it bolts back up with no real problems.
I replaced mine and kept the stock 79 fan cage, and found that was much better. I suspect the C3 blower motors could move pretty decent air when new - but age does take a toll, in my opinion.
However - As AJROTM said, before you go to the trouble of R&Ring the motor, make sure you have a good ground connection on the blower motor with no corrosion, and that the high speed circuit is good - that may be a cheap fix and is at least worth checking.
My experience with weak air flow on my 79, just for reference - On my 79, I started with the ground, and that helped - but not enough to satisfy me. I found a replacing the 37 year old blower motor helped the most. I kept the stock fan and saw a noticeable difference in the motor alone. Keeping the stock fan allowed me to replace the motor without fabricating a spacer.
To get a blower motor, I went to autozone and bought a blower from a later 80s C4 (88 I think), then swapped fan cages after removing the old motor. The flange is slightly different, but close enough it bolts back up with no real problems.
i changed my motor because it was making noise.I put a factory motor back in .I also added a thicker ground wire.check the outer case for leaks[look were the two parts come together] .you can also put in some kind of heat shield between motor and the ac box.water shut off helps the best.
Le Mans Master
Joined: Aug 2010
Posts: 5,339
Likes: 546
From: Central Texas
I did the heavier ground wire first. That helped speed up the fan. I then did the blower fan mod. I just got my a/c fixed. The blower blows much more air through the vents now. I highly recommend both modifications.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,852
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
First I'd make sure the air door is being pulled all the way open..
There is a plastic retainer on the door that can fail. It's a pain to get to and you'll need to pull the main duct out to check it. But if this flapper retainer is broken or if the pod is not working that pulls this door you'll not get full air blowing from the ducts.
Then I would check the function of the vacuum select switch in the heater control.
You didn't say what year the car is but I have vacuum select diagnostic charts at this link.
Once you get there, select the year of your car and then search the word "heater"
http://repairs.willcoxcorvette.com/?yt=&s=air+con
Here is an example of this chart.
If you feel all these things are working fine then I'd upgrade the blower motor. But remember, if the air door is not being pulled fully closed, upgrading the blower motor will only increase the air flow a minimal amount. If the door is working correctly then you'll gain about 20 percent more air flow.
Willcox
There is a plastic retainer on the door that can fail. It's a pain to get to and you'll need to pull the main duct out to check it. But if this flapper retainer is broken or if the pod is not working that pulls this door you'll not get full air blowing from the ducts.
Then I would check the function of the vacuum select switch in the heater control.
You didn't say what year the car is but I have vacuum select diagnostic charts at this link.
Once you get there, select the year of your car and then search the word "heater"
http://repairs.willcoxcorvette.com/?yt=&s=air+con
Here is an example of this chart.
If you feel all these things are working fine then I'd upgrade the blower motor. But remember, if the air door is not being pulled fully closed, upgrading the blower motor will only increase the air flow a minimal amount. If the door is working correctly then you'll gain about 20 percent more air flow.
Willcox
Last edited by Willcox Corvette; Jul 17, 2016 at 09:20 PM.
Burning Brakes
Joined: Oct 2015
Posts: 781
Likes: 113
Might be the damper doors are not properly opening which may make a difference 77-82 has a cable beneath r/s of console that needs to be properly adjusted With a turnbuckle affair to fully close the transition flap in duct system to allow good air flow from A/C etc. Cable connects to a bypass solenoid valve which is accessed if you pull the glove box interior out and take a peek to see IF the bypass is truly functioning with temp set to cold, blower on high and max air switched on..Cable adjustment is accessed by removing R/S of console carpeted panel.Glove box interior is held in place by 6 phillips head screws.Jim here's a good diagram of 77-82 system..
http://www.c3vr.com/member_uploads/1...l-system-2.jpg
Last edited by jim in oregon; Jul 17, 2016 at 09:27 PM.
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Racer
Joined: Aug 2007
Posts: 278
Likes: 0
From: New Rochelle New York
First I'd make sure the air door is being pulled all the way open..
There is a plastic retainer on the door that can fail. It's a pain to get to and you'll need to pull the main duct out to check it. But if this flapper retainer is broken or if the pod is not working that pulls this door you'll not get full air blowing from the ducts.
Then I would check the function of the vacuum select switch in the heater control.
You didn't say what year the car is but I have vacuum select diagnostic charts at this link.
Once you get there, select the year of your car and then search the word "heater"
http://repairs.willcoxcorvette.com/?yt=&s=air+con
Here is an example of this chart.
If you feel all these things are working fine then I'd upgrade the blower motor. But remember, if the air door is not being pulled fully closed, upgrading the blower motor will only increase the air flow a minimal amount. If the door is working correctly then you'll gain about 20 percent more air flow.
Willcox
There is a plastic retainer on the door that can fail. It's a pain to get to and you'll need to pull the main duct out to check it. But if this flapper retainer is broken or if the pod is not working that pulls this door you'll not get full air blowing from the ducts.
Then I would check the function of the vacuum select switch in the heater control.
You didn't say what year the car is but I have vacuum select diagnostic charts at this link.
Once you get there, select the year of your car and then search the word "heater"
http://repairs.willcoxcorvette.com/?yt=&s=air+con
Here is an example of this chart.
If you feel all these things are working fine then I'd upgrade the blower motor. But remember, if the air door is not being pulled fully closed, upgrading the blower motor will only increase the air flow a minimal amount. If the door is working correctly then you'll gain about 20 percent more air flow.
Willcox
Where is the air door located and how do you get access to it so you can visually inspect it and confirm that is working properly with the systems controls on? Also on high fan spped should the air door be fully opened or fully closed/ Thanks
