does your expansion tank have the hose #2 connected to the tank neck.
If so, it will work whether you have a double seal pressure cap or just a single seal cap
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.