Hot and Cold AIR blowing on off.

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luftvagon
Old School!
Location: Little Rock, AR
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Hot and Cold AIR blowing on off.

Post by luftvagon » Sun Oct 14, 2012 3:46 pm

When I move the flaps to cold, and turn off the fan, I still have the hot air blowing into the cabin through the bottom vents in the middle of the dashboard.
The cold air also blows, from the "defroster". Flaps not closing all the way?

On hot, I get cold air mixing with hot air, and de-froster vents are not as hot as they should be.

I'm replacing the master cylinder this weekend, and while I am there... I could fix this too. :thumbright:

81 Vanagon
1981 Volkswagen Vanagon Westfalia - air-cooled Type4 1970cc CV (hydraulic lifters, 42x36 valves, stock cam, microSquirt FI with wasted spark ignition)
1993 Ford F-250 XL LWB Extended Cab 7.3L IDI

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Amskeptic
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Re: Hot and Cold AIR blowing on off.

Post by Amskeptic » Tue Oct 16, 2012 7:33 am

luftvagon wrote:When I move the flaps to cold, and turn off the fan, I still have the hot air blowing into the cabin through the bottom vents in the middle of the dashboard.
The cold air also blows, from the "defroster". Flaps not closing all the way?
If you have the heat lever "off", you should not have any heat, period.
Check actual heat valves for dropped disks. There are two of them, held apart with a spring but tied together with a long "rivet".

The fan is *designed* to blow cold air with the defroster hot air to improve dispersion.
Colin
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 129,490 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 94,225 miles

reluctantartist
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Location: Bloomington, IN
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Re: Hot and Cold AIR blowing on off.

Post by reluctantartist » Tue Dec 25, 2012 12:28 pm

I know this is an old post but I just saw it. I have a vanagon too. I think our heat setup is a little different. We get heat via the fan on the alternator so essentially the heat is always on. Now the flapper boxes have silicon seals that dry out and start to disintegrate after many years which leads to a case of the heat always being on. You will need to remove the flapper boxes and inpsect them. You can get new ones or come up with something to fix the silicone seal. I had one that was missing half of the silicon seal so it was always blowing heat. I got some silicone discs and made a new seal so now when I have the flaps closed there is no heat. As far as the front defroster vents Collin may know more than I. Mine always blow a mix of cold and hot air when I have the heat on, but I do not have any issues with it since it always seems to work well. When you are doing the flapper boxes that would be a good time to look at the rest of the heating system as by this time there are a lot of leaky connections. Mine was barely together above the transmission at a junction point. Now when I turn on the heat there is an audible difference in sound coming from the heat vents. There is actually decent heat in these things last winter when it was 13f out it was ~75f inside.
82 Westy

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Amskeptic
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Re: Hot and Cold AIR blowing on off.

Post by Amskeptic » Thu Dec 27, 2012 4:31 pm

reluctantartist wrote:I know this is an old post but I just saw it. I have a vanagon too. I think our heat setup is a little different. We get heat via the fan on the alternator so essentially the heat is always on.
This is identical to every Volkswagen built since 1963. Whether the source of the air is the engine's own cooling fan, or an assist blower, or the alternator-driven blower, the air supply is "always on". The heat exchangers are designed to cool the exhaust pipes any time the engine is running. The heater valves merely deflect the output from the exchangers to the cabin (when you want heat) or to the outside undercar air flow (if you don't want heat).

If you are getting heat when you don't want it, check the heater valve flappers AFTER you have ascertained that the lever and cables are intact.

You Vanagon owners have a byzantine cable system with little cable sheath clamps that can slip, especially after someone gets all tough on the lever and accidentally kinks a cable.
Colin
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 129,490 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 94,225 miles

luftvagon
Old School!
Location: Little Rock, AR
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Re: Hot and Cold AIR blowing on off.

Post by luftvagon » Tue Feb 26, 2013 9:13 am

One of my cables just recently broke under the dash while I was replacing brake master cylinder. I saw the cable binding to something, and as I tried to move it, it snapped at the lever.. oh well. it looks like a pain to replace them. Servo controlled flaps anyone?
1981 Volkswagen Vanagon Westfalia - air-cooled Type4 1970cc CV (hydraulic lifters, 42x36 valves, stock cam, microSquirt FI with wasted spark ignition)
1993 Ford F-250 XL LWB Extended Cab 7.3L IDI

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Amskeptic
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Re: Hot and Cold AIR blowing on off.

Post by Amskeptic » Tue Feb 26, 2013 8:53 pm

luftvagon wrote:One of my cables just recently broke under the dash while I was replacing brake master cylinder. I saw the cable binding to something, and as I tried to move it, it snapped at the lever.. oh well. it looks like a pain to replace them. Servo controlled flaps anyone?
I think you would be very happy with my Lexus. It is servo-controlled everything . . . with memory sensors.
With 1125 pages in the service manual (two volume set), it has a 120 page diagnostic matrix flow diagram with electrical tests to keep the most restless mind occupied for thousands of enjoyable years.
Colin
BobD - 78 Bus . . . 112,660 miles
Chloe - 70 bus . . . 206,845 miles
Naranja - 77 Westy . . . 129,490 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 94,225 miles

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