10w40 as a hydraulic fluid?

[cmlind]

Our 2 year old Terramite roller screed (concrete) at work has been foaming and puking out its oil. We have been using AW46 hydraulic oil - they even flushed out the system with it thinking it was contaminated.

I read the owners manual and it says to use 10w40 SF/CC/CD motor oil. There is the problem. This is an old spec from 1988. I figure I could use a modern sm/sn 10w40 or 15W40 CJ/SM.

Anyone have thoughts on whether to use 15w40? I would like to use 15w40 since we have it in bulk and do not have any 10w40 on hand. We only use the screed in warmer weather months (above 40), and it warms up fast with a small sump, so I don't think the thicker cold viscosity would matter.

 

[antonmnster]

How many quarts are we talking about?

We have stuff that uses either 10-30 or ATF. 15-40 seems like it's going to at least be very slow.

 

[cmlind]

The sump is about 4 gallons. It doesn't move very fast - has spinning rollers and crawls along slow anyway. I think we are going to try the 15w40 and see how it works.

 

[Sebastian]

As I know, multigrade oils don't foam almost and between a 15W40 and a 10W40 there is no big differece, so I think it will work ok.

Liebherr uses 15w40 in the hydraulics normally.