My 16v was recalled back in 90 by VW for a bypass valve to the heater matrix. I'm restoring the car now and having taken the dash out will change the heater matrix as a matter of course. Do I need to put the bypass valve back in? or should I leave it out? Grateful, as ever, for any advice, thank you.
The original heater matrix was known to sometimes split under pressure and leak "hot coolant" !! over front seat pax legs. The pressure reducing bypass valves were VW's fix. Later heater cores were better quality.