Just an update on the thread, original issue was a torn original monovalve seal. Went through two MTC repair kits with no result.

Found a new Bosch kit (in box) on ebay and it solved the heat at speed issue. Stay away from the MTC kits. One thing I noticed about the Bosch unit is that it had a lot more clearance going into the coil. Both MTC's were a very tight fit.

Always thought the screen was a flow passage.

__________________
2012 B Class

1981 300D - Now with greazzer