radiator end cap plastic repair

[THOMAS TAUSKEY]

The "Snowqueen" - 1993 100CS - has developed a 1 inch long thin crack in the front/middle of the radiator left end cap.   It's easy to get at and the thought occurs to me that a small patch-job (essentially doubling the area around the crack) might hold if it was made out of the right plastic and adhesive.  Sure there's pressure behind it - but there is a relatively large (although curved) surface area to which the patch could adhere.

Any ideas as to what material the patch should be made out of (a scrap piece from another radiator should work, no?)- and what adhesive should be used (urethane based)? 

Thanks. 

tom tauskey
'93 100CS auto (pearl white "Snowqueen")
'94 S4 (garage queen)
'89 2KTQ (hydraulic queen)