[nieuwhzn]

Most of the links mentioned about this on RennTech are broken or just give baby pictures.

This link has a pdf with the repair procedure at the beginning on the thread:
http://www.renntech.org/forums/index.php?/topic/11566-fixed-my-lack-of-heat-problem-here-is-the-procedure/page__p__111502__hl__++foam%20++heater%20+__fromse arch__1

or in case you can't get into RennTech:
http://www4.rcf.bnl.gov/~nieuwhzs/986%20Heater%20Flap%20Repair.pdf