Heating System Explained

Type 2 (T2) Heating System Explained

My apologies in advance if this is a long scrolling page… it’s a long scrolling topic!

I refuse to drive anywhere wearing four pairs of socks, thermal undies, three jumpers and a woolly hat. That’s why one of my first priorities when we bought Daisy in 1998 was to get her heating sorted. None of it worked, so all of what follows is based on extensive personal experience. The reason why many people are so confused about this subject is that many vans are bought without an owner’s manual and neither the Haynes nor the Peter Russek VW Transporter manuals go anywhere near the amount of detail required for the average home mechanic to figure this out. In fact, most garages haven’t the faintest idea how the heating in an air-cooled beetle or van works – so be warned: you will be paying their hourly rate for them to teach themselves how!

In principle…

It works like this. Air is circulated around the heat exchangers which warm the air from heat off the exhaust manifolds. It is pushed towards the cab by both air pressure and at least one fan. That’s it! The diagram shows how…

Type 2 heating system
Type 2 heating system

However, please note that your van will be best served with an exhaust system that retains all of the above components, and performance of your van’s heating will be best improved using original equipment. I know that normally means ‘more expensive’, but the best things in life aren’t cheap but they’re worth it!

1This is the fan, situated either on top of your engine if you have a 1600 or at the back if you have a 2ltr. They both do the same thing – suck the cold air which enters the engine bay from the rear body air intake vents, and blow it via a pair of concertina tubes into your heat exchangers. If your fan is broken or has broken blades or if the shroud is poorly fitted not only will your engine not be properly cooled, but your heating will suffer.

2Heat exchanger - SchematicHeat exchanger schematicThe heat exchangers look like complicated exhaust boxes and when I bought some for my first beetle back in the early 80’s I hadn’t the faintest idea what these bloody expensive boxes were all about. Well they’re dead useful – the cool air from your fan is blown into them and circulates around an arrangement of fins heated via the red-hot exhaust manifolds. The air is then ejected out of the heat exchanger into the heater elbow. If your heat exchangers are rusted through anywhere, your heating will suffer.

3AirflowThe heater elbow is simply a mechanical valve which, when opened, allows the hot air from the heat exchangers to pass into your van. On the 2ltr engine the elbow is a separate part, on the 1600 it is integral to the heat exchanger. As illustrated in the diagram at right, when the valve is closed, the hot air simply escapes outside. The internal hinged flap is operated via a solid cable attached to the heater controls on your dashboard – more about them later. If the hinged flap in either heater elbow is rusted into position or just plain broken, your heating will suffer.

4When the hot air reaches the central collector it is sent two ways: to the front of the van and to the rear via three small rear-facing vents on the floor between the two bulkhead halves. To my knowledge there has never been any lever to manage the flow of hot air to these vents, so on my van I have simply blocked off the tube that feeds these vents as, when I am driving, I want all the hot air in the cab. However, if you regularly take passengers, especially children, you may find these vents useful, but be aware that they are largely ineffective as you would require an additional in-line fan (or something similar) between the heater elbows and the collector to generate the amount of air pressure to heat the rear of the van to any noticeable extent whilst also heating the cab.

5This is the wonderful bit, according to my wife! These are the two hot air vents located behind the kick panels (which should have pre-cut holes to fit around them) which keep our feet toasty warm even in the coldest weather. The vents are operated by a lever on the dashboard – more about that later. There’s also a manual slider on the heater tube that allows you to direct even more hot air into the cab floor. Remember, hot air rises, so if you have it all blowing onto your feet, it’ll eventually get to your face too!

6Finally, the rest of the hot air exits via two pairs of vents in the top of your dashboard. Yes, contrary to popular opinion, they really do work! They are excellent windscreen de-misters and cab heaters. My Daisy has done almost 110,000 miles and is 27 years old and the last 30,000 miles has kept me warm in the worst weather. I’ve also been in the fortunate position of being able to regulate the heat because all the controls are now working, so I don’t bake in the summer!

The dashboard heater controls

On your dashboard you have three levers, two with a red knob, one with a blue one.

1This blue lever is the cold air control to the windscreen and the fresh air ducts at the far left and right of your dashboard and has absolutely no effect on your heater controls. In fact with this control you can have cold air blowing on your face whilst having hot air blowing on your feet. If this control doesn’t work (top is closed, bottom is open), contact me and if there’s enough demand I’ll do a section on that.

2The left red lever pulls or pushes two solid cables (connected via a clamp under the dash) that control both heater elbows simultaneously. When you pull the lever down you receive progressively more hot air, which you can then further control using the right red lever.

3The right red lever pulls a short cable down to a flap set into the hot air riser tube down by your feet, allowing you to open or close the cab kick-panel vents (number 5 in the main diagram). Due to the way the levers are fitted, this one can only be moved down when the left one is also down, but if you think about it, this is perfectly logical Wolfsburg thinking!

The heater cables

Heating cableHeater cable…The heater cables are a bugger to get to underneath the dash, especially if you are 6’1″ and 18 stone and no good at Houdini impressions! However, I did it, so I guess you can too. The cable inners are connected to the heater control levers via the loop in the top of the cable (see diagram) and a circlip to hold them in place. When fitting these cables do not put any kinks in them – they are solid cable, not braided, and any kinks will make them difficult to operate once fitted!

All three cable outers are clamped to a bracket under the dashboard. If this clamp is missing you can almost forget your heater controls. It is imperative that under normal operation the cables are securely clamped in place. I tried various methods (mostly unsuccessful) until I was able to source a clamp from a VW breaker’s yard which, 12 months later, is still in place.

It really is best to do the rest of this job with the van up on blocks or axle stands as, unless you have a radically raised baja van, there simply isn’t enough ground clearance to get all of these jobs done properly. If, however, you are 4′ tall and weight 6 stone, you could do it without the above (but how you got that driving licence, junior, is beyond me)!

When fitting new cables, note the precise route the originals took behind the kick panels and through the cab floor as this will make it far easier for you to fit the new ones. You will have to remove the stone guard underneath the cab to get to the main cable guides. These carry the cables to the rear of the van right to the heater elbow operator levers, and this bit is a doddle.

Cable end with clamp screw shownOnce the ends of the cables have been fed through the guides, you have to feed the end of the cable through the heater elbow lever. It is best to do this with the concertina heater tube removed (see main diagram – just forward of the elbow) as this will allow you to determine where, eventually, to clamp the cable. It is easier to do this with two of you, but I did it on me own just to be awkward! Pull the left-hand heater control all the way to the bottom, i.e. in the full on position. Then get back underneath the van. Insert the clamp screw into the end of the heater elbow lever and feed the end of the cable through the clamp screw. Now, with one hand, pull the heater elbow lever until the flap inside the elbow is in the fully open position, and with the other hand (obviously grasping the appropriate screwdriver/spanner) tighten the screw clamp, making sure that the cable is fully pulled through and straight.

Cable end with molding snipped offNote: some people have mentioned that their newly supplied cables weren’t the right length. I found this to be the case as well, although the part numbers were definitely correct for my year. In my case I just snipped off the metal moulding at the end of the cable and tightened the clamp screw around the cable itself. The most important thing is that, with the other end of the cable firmly clamped at the dashboard end, the cable outer cap at this end is between the end of the cable guide and the furthest forward movement of the elbow lever. Make the clamp screws part of your routine checks – you’ll thank me for mentioning it!

Now return to the cab and move the lever fully into the up position and, underneath the van again, check that the flap is in the closed position. Depending upon the snug fit of the cable, there may be a slight gap, and this will mean that there may be a trickle of warm air into the cab when the lever is up. This is where you play around with small adjustments to get it just right. Now do the other side and that’s your heater controls set up. The only way to test it is to run the van (or fit a reverse blow vacuum cleaner to the system to blow air through).

Finally, there is the short cable that controls the footwell heater vents. This is going to be difficult, not because it’s a pain to fit, but because it’s going to be nigh-on impossible to source a new cable. I still haven’t managed to get hold of one two years later, so don’t hold your breath. However, I have simply locked the flap inside the heater tube in the up position so that whenever I turn my hot air on it hits my feet first (this suits both me and Dannie just fine). The cable itself, if you manage to get hold of one, appears to be simple to fit – nothing as complicated as the other two, so at least that’s a relief!

Common Problems resulting in poor or no heating

I have either experienced the following problems myself or have helped friends discover them in their own vans. They can result in poor or no heating at all in your van – get them sorted and you’ll have a much warmer journey:

  • Non-standard exhaust set-up
  • After-market, ‘cheap’ heat exchangers
  • Broken fan or fan blades (will also affect engine cooling – sort it now!)
  • Poorly fitting fan shroud (will also affect engine cooling – sort it now!)
  • Rusty heat exchangers
  • Faulty/rusted heater elbows
  • Punctured, broken or clogged heater tubes
  • Heater cables not attached to control levers
  • Heater cable clamp under dashboard faulty or simply missing
  • Heater cables seized in chassis guides
  • Heater cable clamp screw loose or missing
  • Heater cable snapped
  • Type 2 heating system

I hope this article helps some of you prevent frostbite this winter!

Frank Wognum

Original location:
http://myweb.tiscali.co.uk/freemefromthishell/vw/Type 2 Heating original.htm

This webpage was posted at the link above by Frank Wognum but the website is no longer online and I was unable to track Frank down. I did find a statement saying he was no longer going to be running his webpage and I felt this it was too good to disappear.

Learn more about my Revival project, any questions let me know.