The people to answer this should be the supplier/manufacturer of the machines.
Normally thinner hydraulic oil and possibly engine oil, higher concentration of antifreeze, but it really depends on what is the standard and what the manufacturer approves of. The list can be endless and depends on what is required.
If you post up the manufacturer, model and options (Cabin?) of the machines in question then you'll be more likely to get the response you need. Also are the machines stored outside or brought inside at night?
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