joepenoso

Heater coolant return line to passenger side, near firewall intake manifold restriction.
The heater hose id fairly large running from the water pump to heater and back to the manifold. The part that threads into the Manifold has a 1/8th" inch hole restriction that necks down and I assume, slows flow. is that correct?........
I thought that the thermostat job was to slow flow?
Just leave it alone?
Curious minds want to know
Thanks
joepenoso

455man

If you are talking about the heater control valve that's normal. It stops the flow of coolant to the heater core when the heater is not on.

droldsmorland

The restrictor with or without A/C protects your heater core from full pressure flow from the pump.
With A/C its part of the vacuum control valve. W/O A/C its a fitting with a hose nipple threaded into the intake. Many have learned the hard way if you eliminate it chances are you will pop your heater core. Specifics depend on model year.

72 w29 all green

I did and with the 455 and A/C, it's a PITA of a job; twice in 10 years is too much .

joepenoso

Thanks
I will leave it alone
joepenoso