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Defrost Question
Posted by: igottajob2 ()
Date: January 23, 2018 11:03AM

So my Defrost doesn't work well at all on my vair. The ducts aren't plugged. I think maybe the duct under the dash doesn't fit quite right and I am losing air. Is there anything else I can check for? Perhaps I need the high output heater motor? Let me know and thanks!


1965 500 Coupe

Built the 1st week of April of 65 at willow run.
500 coupe. The only factory accessory is a rear antenna.
White with a red interior.
Now black with black and red interior.

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Re: Defrost Question
Posted by: MattNall ()
Date: January 23, 2018 11:09AM

Make sure your Fan is CLEAN.... makes all the difference..

Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!

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Re: Defrost Question
Posted by: 65CrownV8 ()
Date: January 23, 2018 04:27PM

Install the fan on a relay. Shortens the amount of impedance the current sees.

George Jones - East Orlando, FL
'65 Monza V8 Convertible - 355/4-spd Posi - TT015
'66 Monza Coupe - 95/PG
'67 Monza Coupe 140/4-spd/Posi, A/C
COrvaiR Society of America (CORSA), Central Florida Corvair Club, Tidewater Corvair Club, V8 Registry

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Re: Defrost Question
Posted by: TerribleTed ()
Date: January 23, 2018 05:03PM

Make sure that the defroster door that actuates with the defroster lever is actually moving and diverting the airflow. How are the seals on it?


Avid Corvair hobbiest since 1984.
I have personally performed ground up restoration on over 20 Corvairs.
I currently work full time at restoring and repairing Corvairs.
Located in the Atlanta Georgia area.

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Re: Defrost Question
Posted by: Vin ()
Date: January 24, 2018 06:22AM

Probably no getting out of checking the system from one end to the other, from making sure lever is actuating the diverter, to verifying no clogs in dash ducts and the long heat duct, to making sure the fan isn't plugged up. I found a dead mouse and nest in my fan, nest material in the long duct, and after replacing the fan and cleaning thought I had it all but some nesting crap blew out of the dash pad where it was wedged in the dash duct.

Dayton, OH
1965 Corvair Monza Convertible (4 speed)

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Re: Defrost Question
Posted by: aircooled6 ()
Date: January 24, 2018 09:35AM

There are only a couple of places for air leaks in the ducting from engine forward. One is the big rubberized hose from the blower box. If that hose is torn or has slipped off either end, airflow will be reduced. The next one, as I recall, is under the back seat where it attaches to the rear heat vent. That can be a large leak if all the foam has failed at the joint. I believe (doing this from memory) there is another foamed joint at the front end of the duct, where it connects to the interior ducting.

Hi Speed Motor? That would be a double-plus good modification, although, even with that, the defrosters are still not the greatest. You'll get a canteloupe sized clear area where the air hits the windshield. That IS better than the baseball sized spots, though.

I concur with using a relay for the mod. Im lazy and simply used the main wire from the switch up front (Orange, I think) to energize the relay and ran a piece of 10 gage from the battery to the relay and then from the relay to the motor. That takes all of the load off the 50 year old switch and only gives you ON or OFF, but face it- in Minneapolis, do you really need anything other than full blast in the winter? Been there, done that and moved to Tejas!

Oh, I put the relay in the engine room, further reducing the length of the hi-power run.

Lastly, do yourself a favor and Peen the center hub of the squirrel cage at several spots around its circumference. It will save you from crawling back under there when it starts rattling due to the increased starting torque of the more powerful motor. Want to guess how I know this?

Do NOT use the plastic fans. They melt. If you cant find a decent old vair one, a substitute is available at the local parts store. Its not quite as tall, but boy does it move air! Its only about 1/4 inch shorter and it works fine. Siemens number BW9302, Four Seasons 35602. Simply adjust where you place it on the motor shaft and tighten the screw.

Everett Wilson
North Richland Hills TX
(Now, South of 820!!)
64 Greenbrier 110 with 95 heads/PG

Edited 1 time(s). Last edit at 01/24/2018 09:38AM by aircooled6.

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