Heater issues

Jiffy wrote:Hi Guys,
I have some newbie questions in regards to the heaters in my 70 beetle. (steel dash)

1) They seem to work intermittantly. One day it will be burning my feet, another day it seems to be pumping air at ambient temps.

Are you pulling up both levers or just the one?
if you keep the back outlets shut and have the front ones open they will burn your ankles.
Also it's rev dependant, the heaters suck idling at traffic lights but 100km/h down the highway they nuke everything within range.

2) I think there is a very slight amount of CO2 coming in... is there any way to test this with a meter (rather than relying on my sense of smell/taste?) I've done a quick inspection of the J pipes and they seem ok from the outside at least.

Check the condition of the donut seal and clamp where the heaterboxes meet the muffler.
As helbus said oil leaks from the rockers covers all over them and eventually finds its way in which stinks them out too.

3) I presume that by closing these vents, it pushes air (or should do) up into the demisters in the corner of the windscreen? What about the little black plastic vents in the middle, do they do anything?

Yep, keeping the back outlets closed (left lever down) and the front footwell flaps shuts forces all the air to the windscreen which is when it comes out all the vents.
The middle vent above the radio should be connected to the Y pipe as well.

4) There is a y pipe where the heater channels seem to come up under the bonnet and connect to the demisters. There is an extra connection that on mine, is just blocked off, what is that for? Is that related to the catcher under the air vent in the top of the bonnet that seems to do nothing other than catch water from the hole and push it down a hose to the ground?

Sounds like your fresh air ducting is missing.
That box has an outlet on either side that feeds fresh air to the vent outlets above the speedo and glovebox and the knobs below the radio shut these off.
the heater Y pipe also feeds into these as well which is probably the other missing hoses

Jiffy wrote:Hi Guys,
I have some newbie questions in regards to the heaters in my 70 beetle. (steel dash)

1) They seem to work intermittantly. One day it will be burning my feet, another day it seems to be pumping air at ambient temps.

2) I think there is a very slight amount of CO2 coming in... is there any way to test this with a meter (rather than relying on my sense of smell/taste?) I've done a quick inspection of the J pipes and they seem ok from the outside at least.

3) I presume that by closing these vents, it pushes air (or should do) up into the demisters in the corner of the windscreen? What about the little black plastic vents in the middle, do they do anything?

4) There is a y pipe where the heater channels seem to come up under the bonnet and connect to the demisters. There is an extra connection that on mine, is just blocked off, what is that for? Is that related to the catcher under the air vent in the top of the bonnet that seems to do nothing other than catch water from the hole and push it down a hose to the ground?

Please excuse my ignorance and I appreciate any help you can offer.

Jiffy wrote:Hi Guys,
I read this post a little while ago and it didn't click. I assumed that the left lever was the left side and the right lever was the right side.
I'll have to go and check that out now....

One thing I did notice though, when the window is open I get a lot more air flow coming out of the heater box. Without touching the heater, if I close the window, the air flow cuts in half.
Why is that?