Forum Discussion

maillemaker's avatar
maillemaker
Explorer
Jun 11, 2018

Can anyone tell me what this coolant line is for?

I have a 1990 Winnebago Warrior RV built on a Ford E350 van. There are, of course, two bypass lines that come off of the water pump and manifold. Normally, these would route to the heater core. O...
wnjj's avatar
wnjj
Explorer II
Jun 11, 2018
RLS7201 wrote:
That line is there to help keep the transmission fluid up to temperature. Note that it delivers hot coolant over the top of the transmission heat exchanger in the radiator end tank.

Richard

So I assume that line is connected to the pressure side of the heater core loop, effectively bypassing the thermostat? That would allow both cabin heating and transmission heating as a priority on a cold (t-stat closed) engine.

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