Engine cooling fan ISX

[Mattman]

Why is the belt slipping?? It should not be even with fan on. Is your fan clutch good and tight when you shake the blades?

Have you tried key on engine off to see when fan clutch releases if the fan clutch was leaking air? Mine would leak air when the air was supplied to clutch to release fan.


Just a maybe that the seals in your fan clutch are leaking and when fan clutch warms up it swells the seals to enough to stop the air leak and release the fan.

Is yours a two speed fan clutch?

Just a few thoughts.

Now it being a paccar truck they love to engage the cooling fan when the AC compressor comes on. First time of the day turning on my AC it is just about guaranteed to turn on the cooling fan.