A simple bicycle hand pump and a length of hose securely attached to the
cap on the expansion tank (the one in the engine compartment, after
disconnecting the small hose) will work fine. You should be able to pump
the system up to nearly 15 psi.

Richard Golen wrote:
> Hi,
>
> Before I buy a new motor for my 87 Westy, I'd like to pressure test
> the cooling system to make sure the problem is, in fact, a cylinder
> head gasket/cracked head leak. I went to my local AutoZone store to
> borrow one of their pressure testers. Unfortunately, their kit is
> only works on US-type radiator caps, not the screw-on VW type. The
> kid at AutoZone said they couldn't order an adapter.
>
> So, does anyone know where I could find, borrow, or rent an adapter
> or a VW-type pressure tester?