Heater Duct Repair
For years now, I have been driving this bus around, and made multple improvements toward getting better heat, but still, it has always been lacking greatly, and never even coming close to producing the heat my old 74 bus did, even though it uses the same engine that came out of my 74.
I always knew if I kept the bus, I would have to get into the heater duct underneath the floor, that runs from the engine toward the front of the bus.
Furthermore, I had been racking my brain, trying to figure out how and why it would lose so much heat, as I just knew the heat exchangers were in good shape, and I had made every attempt possible to seal off any leaks.
The only thing I could figure, was that somewhere in the heater duct, there must have been some kind of obstruction, or restriction to prevent the full flow of heat I should have been getting. I kept imaginig some kind of rats nest, or clog of matting of some sort, that I was going to have to remove, and which was most likely jammed up in the diverter valve flapper.
Well, finally, I got around to doing something about it. I had read on a website somewhere, about how a guy replaced his old heater duct with a piece of PVC. I never did know, as to why he replaced the ducting. Now I know.
When I went to remove the plastic jacket from off around the diverter valve that can switch the heat flow to the rear compartment, or toward the front, I discovered a gaping hole on top of the duct, that could not be seen from below, and it was so close to a cross member above it, that I never had felt it before, even though I had previously felt along most of the rest of the top of the duct, and concluded that it was sound. When I removed the plastic jacket, about a handful of rust and dirt fell down from beneath it. Only the bottom half of the metal hose clamp around the tubing remained.
Well this hole I discovered, was about 2 inches in diameter, and has rusted/corroded through the ducting, right about where the fiber heater tubing (covered with plastic jacket) connects to the rear of the diverter valve.
You cannot see the hole in these pictures, and all I have time for right now, is to temporarily patch it over, until I can get some ducting to replace it with, to be able to finish this project. If I ever get back to it, I'll take a picture of the hole, once I remove what is left of the duct. It has been deteriorating long enough, that some of it just crumbles when touched.
Fortunately, such corrossion is not common with most of the rest of the bus. For now though, I have determined to use part of the jacket I removed from around the valve body, to cover and seal the hole in the duct.
Incidently, in case you were wondering what is that stuff around where the cable connects to the valve body, it is some wadded up masking tape, from when I did the undercoating. I'll remove it, if I ever get a rubber boot to cover the cable sheath end.
