Overheard a guy at the parts counter say he uses motor oil in his hydraulic system

I was picking up oil filters yesterday and this older guy next to me told the counter kid he's been running 15W-40 in his dump trailer's hydraulic tank for two years. He said it works fine and saves him $40 a change. Anyone ever try this or know what actually goes wrong besides the obvious viscosity differences?

2 comments

2 Comments

veramartin29d ago

My buddy ran ATF in his tractor hydraulics for almost a year because he got a good deal on a case of it. Said it worked fine until it got cold one morning and the fluid turned to sludge, blew a seal on the lift arm. Cost him way more to fix than what he saved on oil.

andrew69328d ago

Yeah, but I gotta push back a little on that one @veramartin. ATF has been used in old ag equipment for decades with no issues, sounds like your buddy got bad fluid or already had a seal going bad.