TheSamba.com :: View topic - Simple little question about the Heater Box

Sun Sep 28, 2003 5:37 pm

I am doing my first engine rebuild on my '82 westy and I just pulled the engine today and found that the heater boxes were rusted through in a couple spots. I am only going to be driving my van in the summer so heat really isnt a concern for me, and I was wondering if the heater boxes have anything to do with keeping the engine cool or if I am fine without buying new ones and hooking them up. It would be about $500 for me to replace these and I dont want to if I dont have to; I just didnt know if they had any part in keeping the engine cool. Also not hooking them up will in no way affect the Aux. Heater correct? Place let me hear any feedback you might have. Thanks much, this is my first VW and this board has helped me SO SO much :)

Sun Sep 28, 2003 5:55 pm

Rusty heater boxes can lead to carbon monoxide poisoning. They're air to exhaust to air (hopefully fresh) heat exchangers, and if they're holey, the exhaust has a path into the cabin. I'd recommend changing them, or if you really don't need them, you may be able to eliminate them using j tubes. I'm not sure what the ramifications are of j tubes though. Jeremy

Sun Sep 28, 2003 5:55 pm

Rusty heater boxes can lead to carbon monoxide poisoning. They're air to exhaust to air (hopefully fresh) heat exchangers, and if they're holey, the exhaust has a path into the cabin. I'd recommend changing them, or if you really don't need them, you may be able to eliminate them using j tubes. I'm not sure what the ramifications are of j tubes though. Jeremy

Sun Sep 28, 2003 6:49 pm

Just so we know that we are both talking about the same things, are the heater boxes at the back of the van that hook up to the exhaust pipes then it looks like they connect to a pipe that runs toward the front of the van? When I dropped the engine the exhaust was still hooked up and then there were these two things that I assume are the heater boxes on each side of the engine. I looked on the Bus Boys web site and it looks like they are called heater boxes. What do you mean about J pipes? Just regular pipes to take the place of the heater boxes or what? If I did that wouldn't I just be running the exhaust right in side the van? Thanks for the help.

Sun Sep 28, 2003 7:31 pm

Schmokey
If I can put my 2c worth in.
The heater boxes as far as I am aware are just a metal jackets ( one each side of the engine ) built around the exhaust manifolds, so that air in the jacket gets heated by the hot exhaust metal & can then be blown down to the the passenger compartment by the engine fan +/- the booster fan if you have one ( I'm talking 1973 Bus ).
What comes out the ( forward ) end of the HB is just hot air & will only have exhaust gases in it if there is a leak in the exhaust manifold inside the HB.
I'm fairly sure that the HBs have nothing to do with engine cooling ( unless under extremely hot conditions it may be a way of removing heat from the engine as a whole at the expense of cooking the humans up front )...but I will willingly accept correction on that point.
As far as I'm aware it doesn't matter if they are connected or not...except...if they are connected make sure there are no exhaust leaks ( I think you can take the jackets off tho' I've not done that ).
I'm not sure what J tubes are either.
When I last checked my heating system I noticed that when the heat control flap ( in the metal contraption that plugs into the HB ) is closed, air coming thru the HB is vented out before the control flap into the open air....so if you're not using the heater the warm air goes into the atmosphere , the same as if the HBs weren't connected forward.
Hope this isn't confusing.
Anyone out there, correct me if I'm wrong.
Terry

Sun Sep 28, 2003 9:00 pm

I was going to do some modifications to the heating/cooling in order to get some more heat, then I began to think about how air passes over the various components. I decided against any mods, including some insulation. I want air to pass over as much and as many of these components as is possible in order to dissipate as much heat as possible. Rich
'72 Westy

Mon Sep 29, 2003 12:04 am

Yeah, those are the heater boxes I was talking about. I didn't notice an outlet if the flap was closed though. but I wasn't looking that closely last time I was working in that area. To my knowledge you can get tubes that are basically just the inner part of the heater box, and they are shaped like a j, thus the name. The inportant part is, if there is a breach betwwen the two loops of air and exhaust in the heater box, the exhaust can enter the cabin. If you google it, you should be able to find a link, be sure to unclude type 4 in your search. Jeremy

Mon Sep 29, 2003 7:24 am

unfortunately, no one makes j-tubes for type 4 engines. carbon monoxide is normally not a problem with rusty heater boxes, UNLESS the exhaust is also leaking at the heads, in which case you will get some fume transfer.

Mon Sep 29, 2003 4:13 pm

The exhaust is all pretty new and all of it is solid. So does this mean that I should be fine without the heater boxes? Also the Aux Heater will work just as it always did right? Thanks for the help

Tue Sep 30, 2003 3:52 pm

Yup, the aux heater is a totally seperate system. Jeremy

Tue Sep 30, 2003 6:32 pm

the exhaust is carried through finned CAST ALUMINUM that is surroned by metal sheathing. if the metal sheathing is rusted or full of holes your going to get little to no heat and if your engine leaks oil some ugly smells but carbon monoxide poisoning, no. the exhaust is not carried within the outer chamber.

geoff

ps new ones are expensive and to my knowledge not as good as the original. a good shop can replace the flanges and weld up the heat exchangers. expensive either way.