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Injector cooling fan
In message <firstname.lastname@example.org> "Rob Winchell" writes:
> Silly question: do I have an injector cooling fan on my '91 200Q?
It's a 'turbo' feature, relevant to the 10V engines.
On the 10Vs, the inlet and exhaust are on the same side of the engine block.
On the turbos, our hot little friend is down that side too. The problem arises
when the vehicle stops - the flow of air into the front of the engine
compartment stops, and the heat remaining in the turbo subsystem (lot of cast
iron down there) rises up to just under the bonnet/hood. The German is
"Hitzestau" - heat jam.
The trick is to keep the heat in this area below the point at which fuel under
residual pressure (around 3 bar) will boil. There's a thermoswitch on the end
of the heat shield.
This is a non-issue on a non-turbo (there's no source of heat big enough to
be a problem) and on a 20V (inlet and exhaust are on opposite sides of the
The main feature of the injector cooling fan is a plastic shroud draped over
the cam cover.
UK Audi [ur-]quattro Owners Club