What hydraulic oil in Melroe Bobcat?

What hydraulic oil are you using in your older Melroe Bobcats? I have a 743 and am considering going with NAPA Premium AW32 Hydraulic Oil. Thanks in advance.

I have always run plain 'ol engine oil, 15W40
It will also depend on your climate, my winters never get below freezing, summer gets to 40c, but no way i'm running my machine in that heat

Tazza said:

I have always run plain 'ol engine oil, 15W40
It will also depend on your climate, my winters never get below freezing, summer gets to 40c, but no way i'm running my machine in that heat

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743 and similar machines call for motor oil per the manual.

Wayne440 said:

743 and similar machines call for motor oil per the manual.

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A-mazing.I thought for sure there would be a hydraulic fluid of some sort which would be a step down from the expensive Bobcat hydraulic/hydrostatic fluid, (PN 6904026) and yet not quite the "in a pinch" 10w30 motor oil. My impression is that motor oil is engineered for one purpose and hydraulic fluid for a slightly different purpose. I'm not arguing, just amazed. Thanks for the responses.

portsample said:

A-mazing.I thought for sure there would be a hydraulic fluid of some sort which would be a step down from the expensive Bobcat hydraulic/hydrostatic fluid, (PN 6904026) and yet not quite the "in a pinch" 10w30 motor oil. My impression is that motor oil is engineered for one purpose and hydraulic fluid for a slightly different purpose. I'm not arguing, just amazed. Thanks for the responses.

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My 742 is many years old, and I figure if it has run with motor oil in the hydraulics for this long, it will run with motor oil for as long as I own it. No compelling reason to change something that is working.

Wayne440 said:

My 742 is many years old, and I figure if it has run with motor oil in the hydraulics for this long, it will run with motor oil for as long as I own it. No compelling reason to change something that is working.

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everyone has their own thoughts on the matter, the main point most make against engine oil is the additives the put in it. But then you get synthetic oils now that are meant to lubricate even better, so they perform even better than hydraulic oil.
With that said, I sold a machine to a guy 10+ years ago that only runs AW32 hydraulic oil as it's what he runs in his excavator and didn't want to buy different oil. He has put about 1,000 hours on it and it's still running just fine in Australian heat, so it does indeed work, I just wouldn't recommend it just in case.....

Tazza said:

everyone has their own thoughts on the matter, the main point most make against engine oil is the additives the put in it. But then you get synthetic oils now that are meant to lubricate even better, so they perform even better than hydraulic oil.
With that said, I sold a machine to a guy 10+ years ago that only runs AW32 hydraulic oil as it's what he runs in his excavator and didn't want to buy different oil. He has put about 1,000 hours on it and it's still running just fine in Australian heat, so it does indeed work, I just wouldn't recommend it just in case.....

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Getting ready to swap out the unknown hydraulic fluid in my 743b for 10w30 oil. Current fluid appears greenish-clear. Questions...Planning to pump out the reservoir, swap the old filter for a new one (prime the new one with fluid first) and then refill the reservoir with 10w30. Is there anything else, or can I safely ignore what old fluid remains?? I am thinking I will use generic NAPA 10w30 oil on this fill, then do an early fluid and filter change, this time perhaps with Rotella T4 10w30. That should workout most of my current mystery hydraulic fluid. Thoughts on this? is there a better strategy? Thanks in advance.

portsample said:

Getting ready to swap out the unknown hydraulic fluid in my 743b for 10w30 oil. Current fluid appears greenish-clear. Questions...Planning to pump out the reservoir, swap the old filter for a new one (prime the new one with fluid first) and then refill the reservoir with 10w30. Is there anything else, or can I safely ignore what old fluid remains?? I am thinking I will use generic NAPA 10w30 oil on this fill, then do an early fluid and filter change, this time perhaps with Rotella T4 10w30. That should workout most of my current mystery hydraulic fluid. Thoughts on this? is there a better strategy? Thanks in advance.

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You'll never get it all, oil is in the cylinders, pumps, hoses and motors.
I run the machine at idle and pump it out of the aux hydraulic line into a tank. When it starts to spit foamy oil, shut down, remove the filter or at least drain it. Replace the filter or re-install it and re0fill with oil.
There will be residue in the pumps, so they will not run dry.
If you're trying to remove all the old oil you can, I have done this with water contaminated systems by doing the above, but adding 10-20 litres to the reserve tank, drive around, lifting and tilting the cylinders to move the fresh oil around and repeat the above till the oil is how you want it.

portsample said:

Getting ready to swap out the unknown hydraulic fluid in my 743b for 10w30 oil. Current fluid appears greenish-clear. Questions...Planning to pump out the reservoir, swap the old filter for a new one (prime the new one with fluid first) and then refill the reservoir with 10w30. Is there anything else, or can I safely ignore what old fluid remains?? I am thinking I will use generic NAPA 10w30 oil on this fill, then do an early fluid and filter change, this time perhaps with Rotella T4 10w30. That should workout most of my current mystery hydraulic fluid. Thoughts on this? is there a better strategy? Thanks in advance.

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Universal hydraulic oil is 10w-30 and has addditives. Rural King has it for only $50 for 5 gallons.