ACEA E4-21
ACEA E4-21 oils are Ultra High Performance Diesel (UHPD) lubricants designed for use in severe duty, long-drain applications. Engines that recommend these types of lubricants are not typically fitted with advanced aftertreatment devices such as diesel particulate filters (DPFs).
The main physical and chemical requirements for ACEA E4-21 are shown below.
| Requirement | Method | Unit | Limit |
| HTHS viscosity | CEC L-36-A-90 | cP | ≥ 3.5 |
| Sulphated Ash | ASTM D874 | %wt | ≤ 2.0 |
| Phosphorus | ASTM D5185 | %wt | N/A |
| Sulphur | ASTM D5185 | %wt | N/A |
| Evaporation loss (NOACK) | CEC L-40-A-93 | % | ≤ 13 |
| Total Base Number | ASTM D2896 | mgKOH/g | ≥ 12 |
ACEA E4-21 is typically grouped with a range of other approvals which may vary depending on the viscosity grade. Some examples of approvals that can be targeted in conjunction with E4-21 are Daimler MB-Approval 228.5 and MAN 3277, MTU Oil Category 3 and Deutz DQC IV-18.
Changes
ACEA E4 was first introduced into the ACEA Oil Sequences in 1998. Although the testing requirements for ACEA E4 have been updated with each issue of the sequences it was not until 2008 that the severity was increased. This was due to the replacement of older engine tests with new engine tests.
A number of further changes to the requirements for ACEA E4-21 have been included in the ACEA 2021 issue of the oil sequences.
The changes for ACEA E4-21 are summarised below:
| Test | Change for ACEA 2021 |
| CEC L-101-08 (OM501LA) | Option included to use existing OM501LA data in place of OM471 engine test |
| CEC-XXXXXX (OM471) | New piston cleanliness test added, not required if OM501LA pass is available |