Itinerant Air-Cooled

'70 Karmann Ghia (Gretchen), stock dp, feeble heat, for no apparent reason that I can tell. Heater boxes are in good shape, bellows in place, cables dandy, but very little air making it to the cabin. My current reasoning has led to to think perhaps the heater channels of the car are blocked with rust and crud. Has anyone else had thoughts along this line?.

I thought I might disconnect the bellows and try blowing out the body's heater channels from the interior floor vents with compressed air.

Sound viable? Maybe a small plumber's snake?



neal

I've found some pretty crazy stuff in my heater channels. I use a cheapo plumbers snake. Normally it's mice or squirrel nests your knocking out. Also check the flaps on the heater boxes are opening properly. Good luck!

Not sure how the Ghia's heat is plumbed but in the Buses part of that tubing is a compressed, spiraled cardboard up front. When I did work on my heat I pulled that front tubing down and found that not only was it full of debris but that the spiral, glued part of the inner tube had started to give up and lay inside the tube blocking a lot of the air flow. Something to check if the Ghia has the same kind of plumbing. I have nice strong heat now.

I forgot about those cardboards, airflow is feeble at the window, too. And thanks Bajaman, I think I will be the plumber's snake route.


neal

Top ten reasons for no flow of heat/air to front of vehicle:

1) Mouse nest
2) Mouse nest
3) Mouse nest
4) Heater tubes disconnected at rear
5) Heater tubes disconnected somewhere up front (like in the door bulkhead)
6) Loose or bent heater control cable
7) Loose or bent heater cable control linkage at flapper box in rear
8 ) Rusted shut floor vent valve
9) Rusted out heater channels along floor

and finally,

10) Valve/plate/spring in flapper box in back has rusted, broken and is blocking airflow. This won't be obvious unless you remove the flapper box and take a look at the motion of the valve inside.

Happy hunting, Tim

ruckman101 wrote:'70 Karmann Ghia feeble heat, Maybe a small plumber's snake?

neal

Neal, my Squareback has some plastic ducts under the rear seat area that I don't think you have. When your heater box-to-car bellows attach to the car, can you see how they get to the rocker channels? Check for rust-outs. A plumber's snake might drill right through the wall, so I think I would first try compressed air. Does the Karmann Ghia have those pathetic little paper tubes leading up from the a-pillars to the defroster? My condolences. The good news is that the heat in these little VWs can be quite good.
Colin

Haven't explored the tubes business yet. I'll start slow, compressed air from the cabin back. Cables, flaps of the heater boxes, etc have been gone over a few times now. All seems good at the engine end.


neal

trace it from the boxes forward.

take the tubes off between the boxes and body, run engine, feel the airflow out of the boxes.
Good? reinstall tubes. run engine, check for flow at junctions under rear seat.
Good? Block off outlets under seat, check for flow at front floor vents.
Good? Check for flow at little tubes running up to the defrost.

Where ever the flow stops, check for leaks and blockages in that section.

Shop Vac. First suck, in case there is nasty in the tubes/channels. Then put the hose on the exhaust port and blow to simulate the air your fan/heater box would otherwise provide. Now you can trace the path and hear/feel any air leaks prior to where you want the air to escape (inside the car at the appropriate vent). By sucking first, you don't blow the debris into the car or further down the line making the problem worse.

dtrumbo wrote:Shop Vac. First suck, in case there is nasty in the tubes/channels. Then put the hose on the exhaust port and blow to simulate the air your fan/heater box would otherwise provide. Now you can trace the path and hear/feel any air leaks prior to where you want the air to escape (inside the car at the appropriate vent). By sucking first, you don't blow the debris into the car or further down the line making the problem worse.

Very important point there, Dick, for mouse nest infestations. Wear respirator filter, too.
ColinTraumatizedAtLanval'sVanagon

Took off the accordian pipes, stuck the shop vac onto the channel, pulling backwards, and if the sound of the vac motor is any indication, no blockage. Stymied. No flaps at the footwell, cables are opening the exchanger flaps. Going to button it back up and puzzle some more. Air flow certainly isn't robust at idle. But Gretchen goes back to work tomorrow for Cheryle's work week. Glad we have the studs, it's been snowing all day.


neal

ruckman101 wrote:Took off the accordian pipes, stuck the shop vac onto the channel, pulling backwards, and if the sound of the vac motor is any indication, no blockage. Stymied. No flaps at the footwell, cables are opening the exchanger flaps. Going to button it back up and puzzle some more. Air flow certainly isn't robust at idle. But Gretchen goes back to work tomorrow for Cheryle's work week. Glad we have the studs, it's been snowing all day.


neal

Airflow isn't robust out of the exchangers? Flaps opening in the control valves OK? Collars between front and rear exchangers are on and no leaks there?
Colin

Not all that robust at idle. Blowing pretty strong at driving rpms. Hopefully Cheryle will have to shut it down a bit tomorrow. Collars ok, flaps on exchangers are opening and closing. Not sure why it has been weak. Tomorrow will tell.


neal