Hapy Heat Repeat (Part 1)

Ask anyone who has owned or simply driven an old air-cooled Volkswagen in not-Summer and 9 times out of 10 they will regale you with tales of being cold. These awesome vehicles were designed to have heat, its just that they were also designed to be owner-maintained, and maintaining the cabin climate control is not easy. With aftermarket replacements of J-tubes for heater boxes, cardboard pieces eventually failing over time and long channels under the car (where road salt, etc gets in), it's no wonder heat doesn't make it. Anyway, today's post documents another attempt to get some warmth into Hapy, specifically onto my feet and maybe even onto the windscreen.

Why the Obsession

By now, you must wonder why am I so focused on getting heat into the bus. And I get it. Put on a coat or something, right? Besides, it's not like we really get snow in the Northwestern Willamette Valley. This is all true. For folks who own these cars and busses in genuine snow country, I suspect either they are summer-only vehicles or you are far more brave than I, driving in moon boots or something. Around here, we really only have about 10 weeks of warm-to-hot weather out of the 52 in a year. For the rest of the year it is either cold or cold and raining. Driving around in the cold is not as fun when you're bundled up (ski-gear head to toe) and still cold. Regardless, the temperature is hovering around the dew point during those 42 weeks, and overnight for most of the 10 weeks of warm-to-hot season. In the mountains, it approaches the dew point earlier in the evening and remains later into the morning. So, having a means of getting the fog off the windscreen, and not adding to it, is super important.

The Plan

so it begins

Last November, I posted an update (see: Hapy Update) where I replaced Hapy's crappy glow plugs with a new set. I did not circle-back on that since, but he has started without a hitch all winter. Those plugs are fantastic. The real test will be how well they behave next winter. Anyway, in that post, I mentioned that I had acquired a Maradyne Fans heater unit and shut off the Vanagon rear-seat-heat unit because I believed it had started leaking again. We had a "break" in the weather (almost 10*C / 50*F and only occasional rain), so I took the unit out to Hapy. The think was to remove the old, and swap in the new. Ain't nuttin ever that easy, but it's in now.

Old Heat Exit

The Vanagon rear-seat-heat was suspended from beneath the belly of the bus just forward off the radiator. I had fab'd a custom plenum from the heater unit into the original 3" diameter air channel, run coolant lines along the driver side to feed it and run electrical from the dash to control the fan. I hadn't tried to control the valve, choosing to leave it on or off by setting the valve before a drive instead. I unplugged the electrical first, then the flashing/plenum that routed the air into the 3" channel. Then I set to removing the heater from the underside of the bus. Both of the nuts at the bottom of the threaded bolt supporting the unit had rusted so I had to encourage them with a hammer.

Last, the coolant lines needed to be removed. I held the lines closed with vice grips so I did not lose a bunch of coolant and then set a dishpan underneath so I didn't spread coolant all over the ground when I disconnected things. The lines removed easily enough and a small amount of coolant dribbled into the pan. From this I concluded that the unit had been the source of the leak in the cooling system or there would have been more than the few ounces that appeared. I set the unit aside and shifted to the new heater.

New Heater Hung

mounting angle

For installing the new unit, I started with placement thinks. I wanted it in essentially the same place, running air into the same 3" diameter hole. The force and size of this new unit dwarfs the Vanagon rear-seat-heat unit, however. The Vanagon unit is 6" tall and about 9" wide. The Maradyne unit is also 6" tall, but it is almost 18" wide. The Maradyne unit arrived with a cover that had 3 3" vent protrusions. The outer edges of those protrusions are 13" apart, so I decided I would retain the cover and enclose the vent protrusions inside my new plenum. I was unable to reuse any of the old piece.

After some failed attempts to place the heater straight/level with the ground, I shifted the mounting hardware so the new heater was at approximate 45* angle with the bus, pointing upwards. One would reasonably assume this would cause the unit to hang considerably lower, but because of the placement of the fans, the unit is only about an inch lower. How? Well, in this configuration, the top edge of the heater unit nearly touches the floor of the bus. Neither the Vanagon rear-seat-heat nor this unit could do that in the horizontal position because of all the various pipes running under the floor. In the picture on the right, here, the heater looks much lower than the radiator; that is probably caused by the angle I held the phone. In reality, the radiator is a hair lower. The mounting brackets have 2 holes, designed to be used with the enclosed screws. Yes, that's right, screws, and short ones at that. With this install design weakness in mind, I suspended the heater from a pair of metal tubes under the bus floor with.. wait for it... cable ties. Yeah, that is so RoadKill; I am not a fan of using cable ties this way. Having said that, I have not ever experienced a failure with cable ties, and if my 20-year history with Hapy is any guide I will be up under this bus fairly frequently. So, I will be able to monitor the health of these ties and resolve before any real issue arises.

Plumb It

With the heater relatively stable, I flipped to the driver side of the bus and started working on the coolant lines. As I mentioned in the referenced post from November, I picked up an old-skool control valve. Prior to installing, I noticed that the valve seemed to operate more like a shut-off valve than a gradual taper. When "closed", it was definitely closed, but it remained mostly shut through about half of it's travel, then opened up very quickly through the next 1/4 of it's travel and then that last 1/4 its no more open, in fact it almost seems to close a little bit. So, from closed to open the valve really only had to move a little over 1/4 of it's overall travel. I chose to drill out a little bit of material at the barely open part of the valve so that the first 1/2 of travel now actually opens a little bit near the end of that movement. Overall, I think the open-to-closed is closer to 1/2 the overall travel now.

Once modified, installing the coolant lines part was fairly easy. I cut a short stretch off of the return line, and added that to the return off the heater. To that I attached the valve, minding the indicated direction of coolant flow marked on the side. Last, I connected the supply and return lines and then removed the vice grips. I am not 100% thrilled with the routing of the hoses and will incorporate a 45* angle so they are not forced so route to low. After this picture was taken, I shortened the return line another inch or so to reduce the droop a little bit. I poured a bunch of water into the coolant bottle and called it a day as it was starting to get dark.

Plenum

I returned the following morning to complete the job. In a typical install of one of these Maradyne heaters, either the purchaser connects 3" hoses to the outlets or maybe some directional vents (neither are included). Remaining a-typical, I assembled a 4 sided plenum, like the one before it, held together with the higher-end flashy ducting tape.. The top is a 13" by 5" rectangle with 1" long drop-down sides, with a 45* angled rear tail and an up-turned front (image on the right). The bottom is 13" long by 4" (with 1" drop-sides along the shorter edge) and the plenum sides are right triangles with 4" long sides. Remaining ever cost-conscious, I cut material from the old furnace intake. Recall, it was 15" square, so I cut up one side and got 13" length with 1" for the drop-sides with one cut. I taped on the top and bottom first, then the sides, and closed up all the gaps. I get this is not exactly contours-quality... this is far from that. This is all about getting on the road with whatever heat I can extract from a TDI engine. Besides, the last taped-together plenum lasted a few years and would have continued had I not torn it apart for this install.

Electrical

Before I got started on the electrical, I looked back on the post I wrote about the Vanagon rear-seat-heat fans (See Defrosting - Part 4). I discovered that the fan switch that I bought for that install was the exact same as the one that delivered with the Maradyne fans, just with a different knob. So, while I could run new wires and replace the switch, I didn't need to. So, I didn't. Instead, I cut the 3-wire plug off the fan power wires and the ring terminal, leaving enough material so I could reuse it somewhere later. I added female spade connectors to the four wires. I could easily identify the ground wire and low-fan wire so I connected those and tested the fan. Success! And even on low, this fan is more powerful than the Vanagon rear-seat-heat unit on medium. It probably rivals that unit on high, in terms of airflow, but not fan noise. This is super quiet: no fan noise, only the sounds of the rush of air.

With a multi-meter, I confirmed which of the remaining 2 disconnected wires was the wire for medium. I decided that since I had a strong 12V signal, I would reuse the relays and simply wire up the fan. This was also much easier and it insurers that the wires won't melt when I turn the fan on one of the higher settings. The air flow on the "medium" setting is considerable. Boo and I have noticed that the heat in ToyoTruck is most effective on the not-highest setting, concluding that the air speed is so high on the highest setting, it is unable to pull heat out of the heater core as it passes through. As I wired up the high fan, I considered that we could have a similar issue in Hapy now, and may really only use the lower 2 speeds. Time will tell.

Any time the coolant system is open, there are a series of engine runs or test drives followed by adding water and coolant until it levels off. Since I did not need to drive Hapy during the week following this work, I didn't run the engine. Instead, I prepared for "part 2".

The inlets for the fans are drawing outside air and the control valve is still managed by rolling under the bus. I'll get to the valve eventually, but I don't want to wait too long. The drawing outside air, however, needs to be considered right away. As it is, a drive through one of our seemingly ever-present puddles and I've got warm fog blowing up on the windscreen. At least until I route the fan inlets to the bus interior. Since wet season will persist for another few months, I got after changing the air source shortly after I completed this post. I added the image on the right here to illustrate the first problem I encountered: the return coolant line runs straight through where an air inlet would go. Of course, the support bracket isn't helping either.

Thanks, as always, for following along-