What Hydraulic Fluid should I use with my MTS Machine?
For a full synopsis please see the attached article: The Importance of Hydraulic Fluid Selection
MTS previously used Mobil DTE 25 hydraulic fluid in-house for our servo hydraulic machines. This oil is no longer being made.
MTS now recommends the use of Mobil DTE 20 Ultra Series 24, 25, and 26.
1. Mobil DTE 20 Ultra series family of oils are high performance anti-wear hydraulic oils with extended oil life capabilities and have demonstrated up to two-times longer oil drain intervals versus Mobil DTE25 that it replaces.
2. Mobil DTE25 Ultra is compatible with the current Mobil DTE25 and the two fluids can be mixed.
o However, to gain the optimum product performance, it is recommended to minimize tank commingling for this product change.
o This assumes of course that the Fluid the customer is using is in acceptable condition. Proper FluidCare is best validated by performing periodic MTS FluidCare Oil Analysis.
o IF the As-Found fluid condition is FAILING, It should be immediately replaced before adding any new fluid such as Mobil DTE25 Ultra.
Mobil DTE 10 Excel Series is recommended as a Zinc-Free hydraulic fluid alternate to Mobil DTE 25 when a zinc free oil is required.
In addition, MTS recommends the use of Shell Tellus S4 ME (Extralong life) and Shell Tellus S3 M (Long life). MTS does not recommend the use of Shell Tellus S2.
The testing also examined for adverse effects when mixing Mobil DTE25 with Mobil DTE 10 EXCEL 46 (46 cSt viscosity)Mixing the DTEs showed no adverse performance effects other than the loss of being zinc-free..
Never mix other fluids or use an "equivalent" fluid. Other fluids have caused damage to MTS machines despite their equivalent claims.
You can also use Mobile SHC525 if available but it’s much more expensive because it has a higher flash point.
Note: Shell Tellus 46A was also an acceptable fluid to use but has since been discontinued by the manufacturer.
Notice: There is one exception. For the model 512.04 HPU the recommended oil to use is Mobile DTE 26 due to the higher operating temperature of that HPU.
When adding fluid always use a transfer pump such as the MTS model 590.01 (part number 005-149-201) that can provide 10 micron or better filtration. Most commercial hydraulic fluids, even when brand-new, exceed the maximum amount of contamination allowed in MTS hydraulic systems.
For Suppliers of Mobile Industrial Oils
Mobil Oil Industrial in the United States 1-800-662-4525
Exxon Mobile's counterpart in Europe 420-2-214-56426. Their email is
ExxonMobil Egypt (S.A.E.)
1097 Cornich El Nil St.
Telephone: +202 27916 200
Fax: + 202 27958 221