The air is cold driving in the city and turn hot when on the highway. When I turn the truck off I here a hissing sound. What could causes this?
Jul 26, 2011 at 1:13 PM
DOCFIXIT
✓Experienced Mechanic
18,828 POSTS
O.K. not expansion valve but fan clutch is the problem. When engine cold fan will turn easy at op temp fan should be hard to tuen by hand. check out and replace
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May 13, 2021 at 5:20 AM
DOCFIXIT
✓Experienced Mechanic
18,828 POSTS
P.S. if fan clutch checks out need guage readings
May 13, 2021 at 5:20 AM
DMACK1
MEMBER
2 POSTS
Fan clutch is easy to turn. It will not let me connect the gage, and freon comes out.