Castrol Alphasyn EP 150


CASTROL Alphasyn EP 150 Is a high quality synthetic lubricant


Synthetic heavy duty (PAO) EP gear oils




The Castrol Alphasyn EP gear oil range of high quality synthetic lubricants are based on polyalpha-olefin (PAO) fluids and sulpur phosphorus Extreme Pressure (EP) additive technology providing outstanding thermal stability and high load carrying capacity.
The Alphasyn EP range has been formulated for use in all types of enclosed gears including heavy loaded / shock-loaded gears and bearings where EP properties are required. They are suitable for use in gearboxes where micropitting resistance is required and for a wide range of applications in extreme environments. The use of a PAO basestock provides inherently high Viscosity Index (VI) and low pour points making these products suitable for use over a wide temperature range.
The Alphasyn EP range is fully compatible with nitrile, silicone and fluropolymer seal materials.



Heavily loaded gearboxes subjected to extremes of temperature.
Draw works transmissions on Mobile Offshore Drilling Units and Onshore sites.
Top Drives on Mobile Offshore Drilling Units and Onshore sites.

Approval Status


  • Alphasyn EP is classified as follows:
  • DIN Classification is CLP.


Alphasyn EP grades meets the requirements of:


  • DIN 51517 Part 3.
  • AGMA 9005 – D94.
  • US Steel 224.
  • David Brown Type E.
  • Hansen Transmissions.
  • Flender.
  • Lohmann & Stofferfoht.

Features and Benefits


  • Full EP performance gives maximum protection of gears against wear and shock loading, including protection against micropitting.
  • Good thermal and oxidative stability provides reliable operation and extended operating life when compared to mineral oil based products.
  • Inherently high Viscosity Index makes the product suitable for operations operating over a wide temperature range.
  • Rapid air release and good performance in the Flender Foam Test prevents foaming and bearing damage.
  • PAO based lubricant provides good compatibilty with seals, paints and mineral oil based lubricants.
  • Excellent thermal stability and oxidation resistance.