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About the Letters of Conformance (LoC)

For lubricant marketers
Under the European Engine Lubricant Quality Management System (EELQMS), lubricant marketers or manufacturers making claims against the ACEA Oil Sequences are required by ACEA to submit a Letter of Conformance to ATIEL.

Submission of a Letter of Conformance implies a commitment to develop and manufacture engine lubricants in accordance with the guidelines described in the EELQMS. Currently, over 170 lubricant companies worldwide have signed a Letter of Conformance.

In addition, ACEA members have confirmed in writing that to the extent that they market lubricants under their own brands, their suppliers have all signed the Letter of Conformance, whether or not the ACEA members make claims against ACEA sequences for the lubricants marketed under their label.

The Marketers' Letter of Conformance template can be downloaded below, along with a list of signatories. Letters of Conformance are normally renewed every two years – see renewal process document below.

For base stock manufacturers
Base stock manufacturers, including partner groups, wishing to declare that they manufacture base stocks in accordance with the ATIEL Code of Practice (Base Stock Quality Assurance guidelines described in Appendix B) may also sign a Letter of Conformance.

The Base Stock Manufacturers’ Letter of Conformance is shown in Appendix E of the Code of Practice and the template can be downloaded below.

Signed Letters of Conformance should be submitted to:
ATIEL
Boulevard du Souverain 165
B-1160 Bruxelles
Belgium