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C4 AC blower in an '81


Well-known member
Apr 5, 2004
Jacksonville, Fl
'81 dark blue
Okay, so I saw a thread on this subject on another forum and thought, Hmmm, C4 blower motor for better AC flow, sounds like a winner (I live in Florida where the AC needs all the help it can get). Then I go out to my car to go to work... no AC fan. Talk about timing! So I go to Autozone where a '96 Vette fan motor with fan blade is $30 with lifetime warranty, and I just so happened to have exactly $30 on my rewards card! Is this great or what!

Of course it could not last. I go to take out the old fan. After removing the side vent plate and twisting my hands into all kinds of contortions, I got all the screws, wires and vent hose loose. Not so bad.

Then I realize there is no possible way that fan will come out through any space available. So it looks like if I move the coolant overflow bottle it will come out. But to move it I first have to remove the side air intake snorkel tube (This is starting to become a tar baby). I unbolt the bottle and remove the snorkel tube, but the bottle will not move far enough out of the way. It looks like I may need to unbolt the AC compressor to move it and the refrigerant lines enough to move the coolant bottle (whew...).

My question is, am I going about this right, or is there an easier way to get that fan out (and the larger C4 fan in)? (This is on an '81)

Thanks and God bless, Sensei
Hello There,

I did the same (almost) conversion on my 1982 two weeks ago.
According to the service manual, you have to remove the coolant bottle and move the ac compressor to remove the fan.

I spent an hour trying to find another way and finally gave up. And my motor is pretty stripped down, so I have a lot less stuff in the way than a stock '81 or '82.

I replaced my blower motor with a stock 82 motor, but replaced the 82 fan with a '94 fan. I had to make a spacer because the fan is deeper.

Just the fan made a noticeable difference, but not a dramatic difference.

I didn't put in the new motor because it took a different wiring harness and I wasn't sure what would happen if the new motor drew more current (I'm always afraid I will rewire something and then something will melt).

Good luck and let me know if the motor makes a difference. I'd hate to tear all that apart again, but I've done it 3 times so I'm pretty good at it.

Good luck!!!
It seems to me, That I had to bring it down thru the fender to get it out.
this was a few years ago,though.

good luck!!!
I just did mine, I only replaced the motor as the fan was okay and I don't use the air much anyhow. Yes it is in a tight spot! After I removed all the screws via the side vent and pulled out the unit i disconnected the fan from the motor while still in the car, then the motor will drop down (wiggle it out from the bottom and the fan will follow. To re-connect I put the fan back up into position followed by the new motor and connectd the two and back in position it goes with new sealant! a little time consuming but not too bad and all I removed was the side vent. no removing coolant bottle or AC hoses etc..
Wish I had gotten this reply sooner. I took it all out (bottle, tube, compressor), then I had to take the fan off the motor anyway because the C4 fan/ motor combination would not go in as a unit. Oh well, it's all done and working fine now.

God bless, Sensei
It's not a big enough difference to be worth doing if your stock fan is working properly, but it's worth doing if you are replacing the thing anyway.

From what I understand, the motor itself is actually the same, it is just a different fan blade design, longer with a different blade pitch. (The motor does use a different electrical connector and I had to make an adapter)

While you have it out, be sure to vacuum all the leaves out of the evaporator core!

God bless, Sensei
This sound like a mod that I will not be doing on my car.....:eek:hnoes

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