Fresh Air Hose Base Seals (or as VW refers to them - Fan Housing
to Heat Exchanger Pipe Grommets) are the rubber seals that fit
around the connection tubes that stick out through the rear
engine tin from the muffler. Their obvious importance is to
prevent hot air from the exhaust from getting into the engine
compartment, much like the engine seals. VW used them on all
fresh-air fan shroud equipped upright engines (1963 - on).
During this time these seals changed style twice though, to the
best of our knowledge, they are completely interchangeable. From
1963-1973 the 113119585A seal was used. During the early 1973
production (at least on US-export models) - most likely around
late 1972 / early 1973 - the new thinner 113119585B style was
introduced and used through the end of production. When the
113119585A seal was discontinued, VW superseded it with the
113119585B for all years.
If correctness is what you're looking for, the engine breaks for
the seals are listed below.
AE code engines - all
B code engines - all
F code engines - all
H code engines - all
AH code engines - through AH0075453
AK code engines - through AK0113790
40hp engines (starting with 3949223 or stale air converted to
fresh air) - all
AH code engines - from AH0075454
AK code engines - from AK0113791
AJ code engines - all
AM code engines - all*
* - AM engines were only used in the Things. Per VW's Thing
parts book only the later style seal was used, however it's
plausible that early 1973 production still used the earlier seal
and the parts book simply omitted this information.
1) If you're using an aftermarket exhaust system that forces you
to run an aluminum fresh air hose from the shroud to the heat
exchanger directly, you usually can't use the seals. The seals
are only made for the muffler connection tubes to fit through
and not for the hose itself. We would recommend in these
instances to tape up any gaps between the hose and the tin with
an aluminum heat-resistant tape (normally available at most
hardware stores in both black and silver colors near the
furnaces and hot water tanks).
2) Many vendors not only have the applications for the seals
wrong but also the part numbers on them. For some reason we keep
seeing 113119571 listed as a part number but this is actually
the earlier base seal for the smaller pre-heat hose.
3) When VW increased the size of the preheat hose in 1968 to
50mm, the fresh air hose base seals were used for this hose
also. They changed to the thinner style seal at the same time
the fresh air hose did.
Is our info wrong?