Not as convenient but last summer before the drive to the left coast I simply looped the hose from the water pump to the manifold nipple bypassing the heater altogether. Looped the other hose between the two heater nipples to keep anything out.


Bruce
Old Toy: Ol' Betsy stock 59 Apache SB Stepside (Gone but not Forgotten)
New Toy: 1962 Impala SS Coupe
The Driver: 1990 Toyota truck