The cap can be difficult to get as a DV part but you can also ask for an
80/81 VW Dasher radiator cap.

VW# of the Dasher cap is 321 121 321C

In any case it is a style commonly used on radiators so a similar cap
can be matched up, with a 14 psi or 1 bar pressure, more or less. Be
careful that any cap you use gets a even bite on the 2 tangs that hold
the cap down. Also look at your tank to make sure that both the upper
and lower sealing surfaces are flat. Old tanks are often deformed and
this can prevent a new cap from sealing for long.

Mark

Poppie Jagersand wrote:
> Update on the '82 Vanagon Diesel Westy hot running issue.
>..............
> Pressure cap is now the next suspect. (Since it opens and vents coolant
> into the overflow tank instead of building pressure)
>
> Will try to find a new one. Is the '82 Diesel pressure cap common across
> other VW's (will determine how easily I will find one)
>