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Bug heater problems
shaihulud - July 16th, 2009 at 11:13 AM

I have a 1970 1500 Beetle.

I have just fitted a set of heater air tubes to the heat exchange boxes on the J pipes.

I'm now getting a good flow of heated air to the outlet holes under the rear seats and to the oultets on the side in the front but I cannot get demisting heat to the windscreen.

I've checked all of the demisting pipes in the front. There is an outlet pipe that divides into two on each side, with one pipe going to the demister and the other to the air vent.

The right hand side control lever moves the whole way, but the left hand only moves about half way.

What do I need to do to get demisting?

vw54 - July 16th, 2009 at 04:18 PM

the right turns the heater on check to see if its connected to the heater box lever

the left turns on the heaters under the back seat dont use this one as i lessons the flow to the front you should be able to see the flap vales open n close when pulling the lever

Joel - July 16th, 2009 at 07:25 PM

you gotta have the back outlets and the front foot outlets closed to divert what little heat there is to the windscreen

dont expect miracles from it unless your engines doing 3500rpm flying down the highway

Bookwus - July 17th, 2009 at 12:47 PM

Hiya Shai,

Down inside your A pillar you will find a paper/metal hose (basically the same thing as the heater hoses in your engine compartment) that connects the heater channel at the bottom to the divider cap (that leads to your demister vents) at the top. This hose is prone to failure (usually internal collapse) from moisture and old age. There is an excellent chance that you need to replace this hose.

Joel - July 17th, 2009 at 04:39 PM

no one said thats an easy job though :lol:

68AutoBug - July 17th, 2009 at 11:22 PM

Quote:
Originally posted by shaihulud
I have a 1970 1500 Beetle.

I have just fitted a set of heater air tubes to the heat exchange boxes on the J pipes.

I'm now getting a good flow of heated air to the outlet holes under the rear seats and to the oultets on the side in the front but I cannot get demisting heat to the windscreen.

I've checked all of the demisting pipes in the front. There is an outlet pipe that divides into two on each side, with one pipe going to the demister and the other to the air vent.

The right hand side control lever moves the whole way, but the left hand only moves about half way.

What do I need to do to get demisting?


push the left lever back down and all the hot air will go to the front... at the floor level there should be covers to cover the floor vents so all the air will go to the windscreen..

I have a 1500 beetle with heater boxes etc...
every thing is new though...
Putting Your hand down there to find the old hose
You will need a very small hand and long arm....

once you have pulled the old hose out...
get a piece of hose or PVC that will fit [same size]
and just push it down on to the hose connector at the bottom....

once the floor vents are closed the hot air has to go somewhere....

PS: Wipe the inside of Your windscreen with WD40
it will stop the frosting of the windscreen.[so i'm told]

cheers

LEE

shaihulud - July 22nd, 2009 at 06:26 PM

Thanks for all of the feedback.

I followed up on your suggestions, but I can't seem to get the demisters working. I don't even get a hint of warm air from them.

I've checked the tubes in the front that come up to the demisters and they seem to be OK.

I'm not going to follow this up anymore. I'm getting warm toasty heat in the cab, which is what really matters, so I'm going to leave it there.

Thanks again.

Bookwus - July 23rd, 2009 at 02:50 PM

Hiya Shai,

I realize that you are going to leave the situation as it is, but allow me to offer this as an FYI sort of thing........

The tubes that connect the heater channel to the divider cap are double walled construction. That means the inner wall can fail and collapse while the outer wall looks perfectly good. So, the hose can look good from the outside but be blocked up on the inside.