[Loan Dog]

Hi Korijo, Just funnin' ya! Dave's right, the "heat exchanger" part of the heat exchanger, is simply a place that the hot air eminating from your header pipes is trapped and then flows into the cabin. Usually forced by the blower in the engine compartement. You hope there's nothing in the "tubes inside the heat exchangers" because those tubes are your exhaust headers. If there's anything in them, your engine will be constipated...sorry there I go again. I think you get the picture.
Don