Heat exchangers comprise a finned core which is contained within the body. Hot exhaust gasses passing through the core heat the fins which in turn heat the air which is forced through by the engine cooling fan. The heated air then passes through the heater channels to the interior of the car.
When replacing heat exchangers, as usual you have a choice between expensive original equipment components and spurious versions, Some of the latter may not have a large enough fin surface area, which reduces their efficiency at heating air considerably, so do bear this in mind when considering economies.
The exhaust is a low-cost item which is not really worth welded repair once it begins to blow (exhaust gasses escaping through a hole in the exhaust), because patches will be welded onto adjacent metal which will have thinned through rusting, and severe corrosion of these areas will usually occur very rapidly.
When replacing heat exchangers, as usual you have a choice between expensive original equipment components and spurious versions, Some of the latter may not have a large enough fin surface area, which reduces their efficiency at heating air considerably, so do bear this in mind when considering economies.
The exhaust is a low-cost item which is not really worth welded repair once it begins to blow (exhaust gasses escaping through a hole in the exhaust), because patches will be welded onto adjacent metal which will have thinned through rusting, and severe corrosion of these areas will usually occur very rapidly.
