Is the Pentosin CHF 11S used in our cars sensitive to moisture? I have a bottle from when I added some fluid to my reservoir. I am hoping that I can keep this bottle around for a while and add fluid when needed. If the bottle says anything on it about this, let me just say that it is burried behind a bunch of stuff in the garage cupboards.

 

CHF 11s is a pentosin ( a hydraulic fluid ) and will keep indefinately as long as the cap is on tight. I wouldnt let it freeze in the garage however if your garage is not heated. other than that, you fine.

 

Why, what happens if it freezes in the car, as mine does every winter?

 

I'm sure it's freezing point is well below 0ºF

 

Maybe in Antarctica hydraulic fluid might freeze, but Pennsylvania? Al Gore would be horrified!
Oh, and btw, hydraulic fluid is not hygroscopic, so no moisture absorption, just very slow evaporation. Keep the lid on tight.
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So that is why my power steering was low even though there are no leaks.

 

Yeah, and it's in a hot part of the engine compartment. Good for toasting marshmallows, bad for fluids.
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