MIDNIGHT RIDER
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- Sep 29, 2005
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The wife's truck, 1991 Dodge/Cummins, had a properly operating vacuum-controlled heater-hose shut-off valve.
The vent temperatures on a 90-plus day would hover around 50*.
When I discovered that these factory-installed vacuum valves DO NOT CLOSE COMPLETELY, I dis-carded it and installed a manual ball-valve.
With just that one modification, the vent temperatures went from a mediocre 50* to a bone-chilling 29* .
From what I read and hear, the vacuum valves in most all makes of vehicles do not close completely.
The vent temperatures on a 90-plus day would hover around 50*.
When I discovered that these factory-installed vacuum valves DO NOT CLOSE COMPLETELY, I dis-carded it and installed a manual ball-valve.
With just that one modification, the vent temperatures went from a mediocre 50* to a bone-chilling 29* .
From what I read and hear, the vacuum valves in most all makes of vehicles do not close completely.
