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1324 Review
44 Karma

Review on Four Seasons 74603 Heater Valve by Keith Harris

Revainrating 4 out of 5

Super sensitive to vacuum, 1 lb closes the valve.

Very vacuum sensitive, my 69 GS has about a pound of vacuum, when fully hot the valve closes shutting off all flow. Hot-to-cold flow to see if there's a design flaw in the valve or a problem with my on-car thermal regulator.

Pros
  • Automotive
Cons
  • unreliable