ACEA A5/B5 oils are Upper Mainline lubricants. They are designed for use in high performance gasoline and light duty diesel engines that are specifically designed to use a low viscosity oil. These oils may be unsuitable for use in some engines.
ACEA A5/B5 oils are typically low HTHS (≤3.5cP) SAE 5W-30 based on API Group III base oils. The main physical and chemical requirements for ACEA A5/B5 are shown below:
|HTHS viscosity||CEC L-36-A-90||cP||≥ 2.9 and ≤ 3.5|
|Sulphated Ash||ASTM D874||%wt||≤ 1.6|
|Evaporation loss (NOACK)||CEC L-40-A-93||%||≤ 13|
|Total Base Number||ASTM D2896||mgKOH/g||≥ 8.0|
The low HTHS (≤3.5cP) required by ACEA A5/B5 limits the number of additional performance claims that can be coupled with ACEA A5/B5.
Prior to ACEA 2010, ACEA A5/B5 was not usually coupled any OEM specifications. However, Ford has issued a revision to WSS-M2C913-B which raises the minimum ACEA performance level from ACEA A1/B1 to ACEA A5/B5-010. Therefore, in future some ACEA A5/B5-08 engine oils may also meet the requirements of Ford WSS-M2C913-C.
ACEA A5/B5 was first introduced into the ACEA Oil Sequences in 2004, however, it is based upon the original ACEA A5 and ACEA B5 sequences that were introduced in 2002.
For ACEA 2010 a small number of changes to the requirements for ACEA A5/B5 have been made. These include the inclusion of the new OM646LA engine test, as a replacement for the OM602A, along with increases in sludge handling.
The changes for ACEA 2010 are summarised below:
|Test||Change for ACEA 2010|
|Total Base Number||A new limit of ≥ 8.0 mgKOH/g has been added|
|OM646LA||New test added|
|M111SL||Average engine sludge to requirement to increase from ≥ RL140 to ≥ RL140 +4 standard deviations or ≥ 9.0%|
The introduction of a minimum Total Base Number (TBN) of 8.0 mgKOH/g affects the number of ACEA sequences that can be combined with ACEA A5/B5-08. Prior to ACEA 2010, depending upon the performance of the engine oil, it was possible to combine ACEA A5/B5 with a number of other sequences including ACEA C1 and C2. However, as engine oils meeting the ACEA C Sequences are formulated to a lower sulphated ash level they tend to deliver a TBN of less than 8.0 mgKOH/g. Therefore, with the introduction of ACEA 2010 it is unlikely that engine oils meeting the ACEA C sequences will also be able to meet ACEA A5/B5.
The limits for an acceptable level of sludge handling in the M111SL engine test have been raised to the highest level seen within ACEA, with every sequences now required to provide the same level of performance. Some existing ACEA A5/B5 engine oils will be unable to deliver this performance without being reformulated.
The inclusion of the new OM646LA engine test raises the diesel wear protection performance demanded from ACEA A5/B5 oils.
The relative performance diagrams presented below compare Lubrizol's interpretation of the performance of requirements of the existing ACEA 2007 A5/B5-04 oil sequence with the ACEA 2010 version. As shown, ACEA 2010 A5/B5-10 represents an upgrade in wear protection and sludge handling.