They'll work, but could blow.
Usually theyre pretty weak, as low as 6W, 10W to 20W for factory.
10w-40, 20w-40 & 20w-50 are best grades, Brand which i preffer is "ZIC"
10w 40 or 20w 40 either one
-2w+14+10w=348w=20w=2.5
5W-30
As far as I know 10w -20 hydraulic would mean that it is a 10w that will protect to -20 degrees. So, yes it would be the same except for listing what temperature it would protect down to.
Users Manual recommends 10W-40 but anything up to 20W-50 will also work
Petrol engines cold climate 5W/30 moderate climate 10W/30 alternate grade 10W/40 hot climate 20W/40.
4 stroke oil 20W 50 or 10W 40 doesn't really matter
10W/30 ILSAC GF2 or use SG,SH,SJ 20W/50 or 15W/40
10w/30 10w/40 in -5 to 100 degree ambient temperature 10w/50 15w/40 15w/50 20w/40 20w/50 in 15 to over a 100 degrees ambient temperature 5w/20 5w/30 5w/40 below 0 degrees ambient temperature all stats come from original factory maintenance handbook for jaguar xj6
10W-40 normally or if the engine has any knocks or ticks you can quiet it down with 20W-50