1990 Cherokee pre-heater function
11-29-2019, 11:27 AM
#1
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1990 Cherokee pre-heater function
How does the pre-heater valve on the air box function?
Does the valve open on cold start up to draw air from the side of the air box rather than the front until it reaches some pre-defined temperature?
The reason why I ask is if I delete the pre-heater ducting will the valve always be open drawing air from the side of the air box?
Does the valve open on cold start up to draw air from the side of the air box rather than the front until it reaches some pre-defined temperature?
The reason why I ask is if I delete the pre-heater ducting will the valve always be open drawing air from the side of the air box?
11-29-2019, 11:42 AM
#2
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Join Date: Oct 2019
Location: Current XJ is
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Year: 95
Model: Cherokee (XJ)
Engine: 4.0
It improves cold engine idle, winter weather running and quickens warm up. Deleting the duct deletes the heated air. I forget at what temperature the vacuum switch flips the air door from the side to the front.
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