Originally Posted by
alloro
IMO don't install it period. Installing the tee creates a restriction in the heater hose due to the OD of the tee being equal to the ID of the hose. The end result is less coolant flow into the heater core and less heat output from the core.
I always disconnect a heater hose and connect the garden hose directly to it.
F150's and Expeditions already have a restrictor in the hose that's smaller than the Prestone kit's adapter. As sensitive as the heater cores are on these vehicles,it's not a bad thing to have an extra restrictor in the heater core inlet to help prevent leaky heater cores.
JL