I have been advised that my 'heater box' ,or boxes, need changing. I didnt even have heater boxes in my last Bus. The problem is loud engine noise and backfiring (when taking foot off the gas)

What does a heater box do? Is it just for the heating system? Why is it so important to ensure they are functioning properly?

Thanks

[Edited on 20-9-2003 by 4 of 50]

Do you mean heat exchangers? If the bus is backfiring, it could be caused by a hole in the exhaust pipe which runs thru the centre of the heat exchanger. This means your heaters will be blowing exhaust gases into the cabin, 'nuff said:puke

loud engine noise is a stuffed exhaust (maybe heater box problems)
backfiring is caused by your timing, maybe its out or the dizzy needs an overhaul, or it a wrong dizzy for the engine.

Thanks very much for that. Indeed, there are fumes in the cabin when the heaters are on.

guaranteed the backfiring is the result of a leak in your exhaust system. Cold fresh air is dragged into the muffler when the air (fuel air mixture from engine) coming through (with foot off the pedal) is rich and reignites. Spectacular, or spectactularly annoying.
Fix up the leak and your backfiring will be no more.

My thoughts exactly Vassy.
FIX IT QUICK 4!! Exhaust fumes are VERY bad for you, especially in an enclosed space like a car (or kombi). Lots of CO, kills you and you don't even know it's there.

as a matter of fact that may be why my neighbours dog expired (after a long jaunt in the country with fumes aplenty) You reakon that was CO?