Inadequate Heat In Air-Cooled Vanagon

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davebrossi
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Inadequate Heat In Air-Cooled Vanagon

Post by davebrossi » Mon Nov 03, 2014 12:10 pm

Hi All,

Fresh off a clutch replacement and a tune up my van is (other than a vampire draw in current likely tied to substandard wiring on my part) going well. The one exception is the heating system. I found the flapper valves needed the barrel nuts adjusted and did so, the valves themselves are in very good shape and don't stick. Yet when I leave it idling for 20 minutes on a day below freezing, I climb in to drive and the interior temperature can best be described as mid 40s. I know the system utilizes heat exchangers and is driven by a fan running off the alternator to transfer heat from the engine bay through the exchangers. But beyond the condition of the lines (I've checked them, they're all in good shape) where could the heat be going? I get hot air at idle (barely) but when I activate the squirrel cage my choice is between cold and cold. Something I've forgotten to check?

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Amskeptic
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Re: Inadequate Heat In Air-Cooled Vanagon

Post by Amskeptic » Mon Nov 03, 2014 3:45 pm

davebrossi wrote:Hi All,

Fresh off a clutch replacement and a tune up my van is (other than a vampire draw in current likely tied to substandard wiring on my part) going well. The one exception is the heating system. I found the flapper valves needed the barrel nuts adjusted and did so, the valves themselves are in very good shape and don't stick. Yet when I leave it idling for 20 minutes on a day below freezing, I climb in to drive and the interior temperature can best be described as mid 40s. I know the system utilizes heat exchangers and is driven by a fan running off the alternator to transfer heat from the engine bay through the exchangers. But beyond the condition of the lines (I've checked them, they're all in good shape) where could the heat be going? I get hot air at idle (barely) but when I activate the squirrel cage my choice is between cold and cold. Something I've forgotten to check?
Identify your vehicle somewhere in your post.

The squirrel cage fan does not take engine compartment heat, but it does take engine compartment air. It only takes on heat from the exhaust pipes inside the exchangers.

These cavernous interiors radiate heat rapidly through the glass area. There is no way you are going to heat the car at idle.

You absolutely must not leave your VW idling for twenty minutes ever, but especially not during cold weather. It is bad for the engine. The owner's manual says drive off immediately and gently for four or five minutes. We have to get the engine warmed up fully as quickly as possible. Having the engine working under load and at operating rpms will help. You need to thoroughly check the heater ducts for cleanliness and openness, you need to make sure that the distribution box under the center aisle is switching correctly, and you need to know that the air distribution lever will shut off heat to the cabin outlets and give it to the driver's compartment. Look for the double-down arrows and the single-down arrow. You want single-down arrow, to give heat to your feet, to heck with your passengers.

Please note that if any of the controls at the dash feel resistant, they may be suffering the famous Vanagon botched-up cable syndrome. They are poorly anchored at the "control head" and if they kink, they will not actuate your orders worth a damn.
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

davebrossi
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Re: Inadequate Heat In Air-Cooled Vanagon

Post by davebrossi » Tue Nov 04, 2014 9:42 am

Hi Collin,

Sorry about that! it's a 1981 Vanagon. This is what I get for getting the manuals botched up I guess. Easy fix on the starting and idling, so there's one bad habit kicked. I also didn't have the distribution lever set correctly, so yet more to learn here. The only cable that gives any resistance per say is the 'temperature' slider which hesitates right at the last half centimeter. When I pulled the dash this last summer everything appeared properly mounted to the control head, and so I left the cables alone.

That said I -have- adjusted the barrel nuts on the other end of the cables, so I should probably revisit those. Beyond the squirrel cage assembly at the top of the engine, in looking at the Ratwell guide to the 72-79 Bus Heating System (I imagine there are changes, but 79 was the closest to my year I could locate online) I noticed there are a set of flaps at the base of the fan shroud that prevent air that has passed through the heat exchangers from being sucked back into the engine area. Did that design carry over into the Vanagon refresh?

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Re: Inadequate Heat In Air-Cooled Vanagon

Post by davebrossi » Tue Nov 04, 2014 9:57 am

They're labeled "2. Control flaps (blue)" at http://www.ratwell.com/technical/Heating.html . Sorry for the linking, for my part nominal aphasia is a real problem sometimes :-)

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Re: Inadequate Heat In Air-Cooled Vanagon

Post by davebrossi » Tue Nov 04, 2014 12:38 pm

...it may also have something to do with the fact that I'm missing the passenger's side heat riser elbow :geek: and here I found myself wondering "Why does my engine have a line from the fan to nowere?" :compress: made me think of those roads the Irish government had built to nowhere during the potato famine! :study:

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Re: Inadequate Heat In Air-Cooled Vanagon

Post by Amskeptic » Wed Nov 05, 2014 6:00 pm

davebrossi wrote:...it may also have something to do with the fact that I'm missing the passenger's side heat riser elbow :geek: and here I found myself wondering "Why does my engine have a line from the fan to nowhere?" :compress: made me think of those roads the Irish government had built to nowhere during the potato famine! :study:
Let us know how much better the heat is.

At least the Irish were famished . . . our piggy Ted Stevens/Sarah Palin tried to build a 368 million dollar Bridge To Nowhere in Alaska, they ended up not building the bridge, but they did build the highway that would have led to the bridge for cool 25 million dollars. That would have paid for a nice auxiliary heater in your Vanagon.
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

davebrossi
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Re: Inadequate Heat In Air-Cooled Vanagon

Post by davebrossi » Thu Nov 06, 2014 10:30 am

I'll say o.o

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