Fan Speed

[cmillsap]

Hi Al,

Interesting that both issues are related in that the Hayden cools the hydraulic fluid that drives the coolant fan.

On your LXi, I think there is no temperature gage that monitors the hydraulic fluid. So I would be checking to see if the 2 fans attached to the Hayden radiator are operating properly. This can be done by simply jumping the two wires located on the bottom of the blue hydraulic fluid tank at the Aquastat. Also there is a 30A fuse for those Hayden fans located in the remote engine start cabinet in the engine compartment. On my 2000 LXi (the same as yours) that fuse was in line to both fans.

If (for whatever reason) the coolant fan is running constantly at full speed, it may be possible to overheat the hydraulic fluid if the Hayden fans are not operating to cool it off. This in turn could cause excessive expansion of the brass Hayden components and break a seam or weld.

If you find the PWM valve is defective, I have a used one that I believe to be working properly which you can have. Last I heard a while back, they are normally not stocked and are built to order but that may have changed by now.

Chuck