Sulphated Ash

Sulphated Ash laboratory evaluation method ASTM D 874 is used to determine the sulphated ash in unused lubricating oils containing additives and from additive concentrates used in compounding.

ACEA 2008 Specifications

The sulphated ash evaluation is part of ACEA 2008 Specifications:

ASTM D 874 Test Parameters

These additives usually contain one or more of the following metals:

• barium
• calcium
• magnesium
• zinc
• potassium
• sodium
• tin

These elements can be present in combined form:

• sulphur
• phosphorus
• chlorine

The sample is ignited and burned until only ash and carbon remain.

After cooling, the residue is treated with sulphuric acid and heated to 775C until carbon oxidation is complete. The ash is then cooled, retreated with sulphuric acid, and heated to 775C to constant weight. The sulphated ash can be used to indicate the concentration of known metal-containing additives in new oils. The result to the nearest 0.001 mass% for samples below 0.02 mass% and to the nearest 0.01 mass% for higher levels are reported as the sulphated ash.

Pass / Fail Criteria

The pass/fail criteria include maximum variation of characteristics after immersion for 7 days in fresh oil without pre-aging.

*Association des Constructeurs Européens d'Automobiles / European Automobile Manufacturers Association.