Not a Water Leaker

The early Vanagon gets a pretty bad rap.  After years of service, their cooling systems start to break down and pop leaks.  Oftentimes, owners will perform "for now" changes that become permanent.  This increases the bad rap, when its really a case of owner abuse, and misguided group-think.  It was these kinds of things that awarded it the nickname "WaterLeaker".  Knowing what issues the Vanagon encounters gives perspective on my water-cooled bus.  I'm going to hit on that today, with an update on my cooling system testing.

Rad Placement

Vanagon cooling system '83-'86
pic from BusDepot

Consider first, the location of the radiator.  It sits on the front of the Vanagon like any other car or van.  Unlike any other car or van, however, the engine sits in the very back.  This creates a cooling circuit like none other in that the coolant moves 15 feet forward and another 15 feet back.  This distance is ripe for problems. Often, the pipes that run along the under-body are attacked by rust.  If the wrong kind of water is put in the system, the rust can attack from the inside as well!  Once it starts, it is hard to stop, and for a long time replacement pipes were unavailable.  They are now, but they are spendy.  More often than the main pipe rusting, the couplings fail.  These can be replaced a little more easily (but it still ain't easy!).

Rear Heat
The rear heater is most often the source of leaks.  Not the core, mind you, but the circuit to and from.  So, many owners turn off the rear heater by disconnecting the cable and shutting off the valve.  The owner is sitting in the front where there still is heat, but woe to the rear-seat occupant on a winter's drive.  It's like driving around in an old (ill-repaired) air-cooled bus back there.  Grab a blanket!  Usually, its the connecting rubber lines that fail, but by turning off the valve, no coolant tries to rush through the lines and it seems like the problem is solved.

Front Heat / Defrost
The front system (core) rarely is the leak cause.  This is fortunate, but it is one more location where the coolant goes.  Unlike the air-cooled bus where the long runs for the defroster are handled with an air-tube, the Vanagon leverages the front radiator to get coolant to the front of the cabin.  This poses junctions, more hoses and valves, and with each additional junction, there is opportunity for leaking.

Bus?

pressure testing cooling system

So, what does this have to do with the bus?  Great question; I was getting to that.  The implementation in the bus is a franken-system that is part air-cooled / part water-cooled.  With the Jetta radiator under the belly, I have some of the benefits of a more typical radiator system in that the circuit is not 30 feet long.  Its closer to 10 (still long).  My heater core (Vanagon rear-seat unit) sits in the engine compartment.  The distance from heat source to heater core is probably less than 2 feet, so it is more responsive than a Vanagon system.  I am leveraging the front third of the original air-ducting (this is the air-cooled part), so no coolant moves past the mid-point of the bus (the front edge of the radiator).  This means that when there is a leak in the bus, I have 1/2 the area to search for it.

Pressure Test Results
I did the pressure test using the Mity-Vac, but I was only able to get the air-pressure up to around 10psi (pounds per square inch).  Even that took lots of pumping.  If you look at the picture above, you can see that I attached through the overflow bottle.  When it was at 10psi, the coolant level was pushed down below the low-point on the fill indicator.  When I released the pressure, it popped back up to just under the completely full line.  I took that to mean that there was sufficient pressure to force a leak had there been one.  There wasn't.

I'll test drive this weekend around tax preparations, and a dash to the mountain on StuporBowl Sunday.  Don't get me wrong, I love football, but the SuperBowl has become a media circus where the ad's and the halftime show take center stage... and the game usually sucks.  The NFC and AFC Championship games (and the other playoff games), on the other hand, were fantastic.  More next time...