Hi. Anything I can do to the heat exchangers to clean/service them? And does 'lagging / insulating the long main tube under the bus help.?
You can blast them out with air, but not much else. You can have a look inside and see if you have original or repro the originals are better and have more fins ( 8 ) than the repro’s Then lag all the pipe work and check for leaks along the entire system before you do. Any leak will make the system poor. Get it right and the heating is very good.
Dismantling and doing a visual on all the parts they’re pretty straightforward to work out really. Both heat exchangers go into a Y piece the Y piece channels the air flow into the main pipe that runs the length of the bus to the front totem pole. The totem pole feeds the vents in the window and your feet if the blanking piece halfway up is operating properly. It’s easy to go through it bit by bit sealing leaks. At a push gaffer tape works as a temporary fix. if the Y piece is rotted through it’s a pig to change so try fixing any leaks in it in situ rather than replacing it. Ask me how I know!
I have same issue. First thing I was going to do was put a plastic food sandwich bag over the cab outlets and turn on the snail fan to see if I’m getting flow. If no flow then check for leaks. Sound reasonable?
I was just tackling my system. The metal casing around the heat exchangers can be uncrimped and there are 3 or 4 spot welds to remove. I've done this to repair a couple of holes in the casing and I want to reinsulate the insides. A bit of scraping and wire brushing later: I'll give these a coat of VHT primer and then VHT paint, inside and out. I'll just give these a going over with a wire brush: That's as far as I've got. Ordering the insulation for the H/exchangers tomorrow and some material to lag the pipes all the way to the front - yes that makes a huge difference.
Good job.. I don't have a 'snail fan' is that something you added on. Could I buy and use an in line fan? And put it at the begining of the long tube.
Your bus would have had one when it had the type 4 engine. Type 1 don’t have a snail fan. If you fit an in-line fan put it at the cab end; it could overheat if it’s close to the heat exchangers.
Mine was originally a minibus and had an outlet between the front seats. I have blanked it off as no longer required and to give more air flow to the screen/ footwells
While you’re overhauling the system check for fumes and the possibility of ingress into the warm air system resulting in an exhaust smell in the cab. The HX’s should be solid with no holes in the inner j tube ( exhaust ) Any oil leaks from rocker covers that drips onto the HX’s should be cleaned off and the leak remedied. The foam seal around the engine tin should be complete to seal lower exhaust emissions entering the upper engine bay. All breather pipes including the join piece behind the spare wheel well should be intact. All excess oil on engine above the tinwear should be cleaned up and the reason for the leak addressed. The cool air entering through the rear quarter panel fins supplies the fresh air through the heat system as well as cooling the engine oil.
I've yet to investigate properly, but I had smoke coming out of my cab vents recently when I pulled up in traffic. I'm thinking it might be coming from a leaking crank seal, which is right behind the fan on a T4.
Mine is a type 4 (South African) but had no snail fan fitted although the bracket was there. I bought one off Mr Davidoft and fitted it. Yes I'm fitting an online fan which I've bought: https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/181640261890 You need a specialist switch to adjust the speed as a normal variable resistor switch won't work. You need a constant 12v to make the motor spin so a variable pulse switch is needed, I can't find the link to the one I bought but something like this: https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/372632882198
