Viscosity of Monograde and Multigrade Oils - Amsoil

TSB: MO-2006-05-01Date: 05/01/2006Technical Service BulletinProduct Description: AMSOIL 10W-30/SAE30 Motor Oils (ACD and ASE)Subject: Viscosity of Monograde and Multigrade OilsSAE 20 and SAE 20W are two totally separate monogradeclassifications. SAE 20 describes the high temperatureviscosity of the oil and SAE 20W describesthe low temperature cranking capability of the oil.In order to allow engines to start at low temperatureswhile providing sufficient viscosity at high temperaturesto protect engines against wear, multigrade oilswere developed. An oil can be classified as a multigradeSAE 20W-20 if the oil can meet both the lowtemperature cranking viscosity of 4500 cP at –15 o Cand the 100 o C high temperature kinematic viscosityrequirement between 5.6 and 9.3 cSt.Typically, a type of additive called Viscosity Modifier(VM) or Viscosity Index Improver (VII) is added tothe base oil to achieve multigrade performance.These types of organic polymer additives thicken theoil at high temperatures while having a minimal thickeningeffect at low temperatures. The addition of aviscosity modifier allows for the use of lower viscositybase oils to achieve the cold temperature requirements.The use of light weight petroleum oils increasesoil volatility (burn-off), contributing to excessiveoil consumption and oil thickening.RECOMMENDATIONSAMSOIL ACD and ASE 10W-30/SAE 30 engine oilscan be used in any applications requiring a monogradeSAE 30 or multigrade SAE 10W-30 engine oil withthe performance specifications listed for each product.AMSOIL ACD has a performance emphasis on heavyduty on-road diesels with an API CI-4 Plus rating,while it is also applicable for gasoline engines with itsAPI SL rating.AMSOIL ASE has a performance emphasis on smallgasoline and diesel engines used for commercial serviceor by the homeowner. AMSOIL ASE carries theAPI SL rating for gasoline and API CF/CD rating foroff-road diesels.REFERENCES1. Society of Automotive Engineers, Publication J-300, December 1999.AMSOIL Heavy Duty Diesel Oil (ACD) and SmallEngine Oil (ASE) meet multigrade viscosity requirementswithout the use of viscosity modifiers. This isaccomplished through the use of naturally high viscosityindex, wax-free synthetic oils. These oils meetboth the low temperature requirements of SAE 10Wand the high temperature requirements of SAE 30.Thus the products are true SAE 10W-30 and SAE 30oils.Submitted By: DW/DY Reviewed By: DY Approved By: Alan Amatuzio Approval Date: 5/05/06Distribution: ___InternalX AllPage 2 of 2AMSOIL INC., AMSOIL Bldg., Superior, WI 54880 (715) 392-7101 © Copyright 2006