Let’s talk about the heater systems in these air cooled VWs. This is the only car made that you can get 3rd degree burns on your left foot and be frozen from the waist up. If you go through the whole system and fine tune it, the heater will work, just don’t leave any plastic shoes near the floor vents.
First thing to do here is to jack the car up, slide under the motor, and find your heater boxes. If you don’t have any heater boxes that’s probably a good reason why your defroster doesn’t work. You can either buy some or get an ice scraper. Now that you have found them, look for where your heater cables attach. Are they connected? Hell, does it even have cables? If your cables are there and hooked up, crawl back out and turn the heater on all the way. In other words pull the lever so the boxes open up. Do not start the car. Crawl back under the car and see if you can push the levers on the boxes farther forward towards the front of the car. If you can, then readjust the barrel bolts that are on the cable so that when the cables are in the full on position, the levers on the boxes are also full on. Now sometimes this means that when the heater is off that the box levers are not all the way off. Well in winter I’d rather have full heat, just readjust them in Spring if you want.
Second thing to do is to look at the hoses that go from the heater box to the body. Are they there? If not, your heater system will do a fair job at heating the trans but you won’t see any air in the cab. If the hoses are there, check to see that you have a nice tight fit to the body as well as the heater box. I have even used duct tape to insure a good seal here. These hoses from the factory were insulated, make sure yours are too. Early buses had metal hosing and most of the time the insulation is gone. Do something to insulate it. What ever you use make sure it is water proof or your tubing will just rust out.
Now to the inside of the cab. Find where the heater channels branch off. For instance, on a bug they have a vent under the rear seat. Are the flaps in that vent? Is the cable hooked up? If you don’t care about heating the back of the front seats and your flaps are gone, just plug that vent up. Make sure you don’t use anything that will melt. Also, while you’re under the back seat, that branch we were talking about should be insulated. On early bugs and ghias you will see a bulge in the piping. That is a silencer, a kind of muffler where the inside is insulated. On the later bugs, they did away with that and just had a “Y” there with a wrap over it. Make sure the wrap is still there or re-wrap it. Buses are a different story. One heater box goes to a vent under the rear-most seat and the other box went to the front. Again, on a bus follow your heater tube to the front and make sure there is some water proof insulation on it.
Now the fun one; Bugs, Ghias, and Type 3’s all have a hose that comes up from the floor heater channel up to the defroster vents on each side of the car. First, look at the hose that comes down from the defroster. Is it still connected? If so, you’re good to go; If not, you’re in for some work, those hoses are a bitch to replace. I have found that cutting an access panel with my dremel tool is the best method. This is done inside the car, down by where the heater channel is. I cut a tab and bend it back. This allows me to get what’s left of the old hose off and clean out the 40 plus years of crap that has accumulated as well. Don’t be surprised if you find tools, coins, bolts, etc. in there; This area is kinda of the abyss of these cars. When replacing these hoses, I like to use the german paper hose and not the silver aluminum looking hose. The fit is much better and tighter with the german hose. If you are fighting to get these hoses, on you’re doing it right. The early bugs just have one tube that comes up to the corner defroster vents, nice and simple. Starting in 1967 they started to put splitters on this hose that comes up from the floor and had more vents across the dash, more of a pain. The good news here is if you take the time to get them all hooked up with a nice seal on all the hoses, your defroster will defrost more of the front window. You can leave that rag in the glove box that you were wiping the window off with. On cars with a fresh air box, I usually take where the defroster vent goes into the box and make a temporary plug here so no cold air goes into my defroster vents. In the summer, you can pull the plugs back out so the air box can put outside air in the defroster vents. On buses there is not much to do in the front because most of that ducting doesn’t really go bad. The only thing I can say here is, on buses up to 1967 make sure your fresh air box has good seals in it. On the later buses, make sure the fresh air doors are closing all the way.
If you do all this the heater will work. Not as good as a water cooled car, but none the less you will be amazed at how well it works. Those of you who don’t have heater boxes or don’t want to do this all this work, I hear they’re having a sale on jackets and ice scrapers at Walmart.