ExxonMobil officials say sediment found in a select number of quarts of Exxon Aviation Elite 20W-50 oil is harmless to aircraft engines, but the company will nonetheless replace unused quarts at no charge. An AOPA member alerted the association Wednesday afternoon when he noticed sediment in the bottom of a bottle of the oil. AOPA was expecting to receive a case of the contaminated oil Friday morning and will submit it to independent labs for testing; ExxonMobil will also examine the samples.
The company discovered in August that about 1,100 cases of the oil distributed in early summer had been contaminated with small amounts of fine metal particles from a wearing pump used in the manufacturing process. ExxonMobil alerted its distributors at that time and offered to take back any unsold oil. The metal particles settle out of the oil during shipment and adhere to the bottom of the bottles even when the oil is poured into the airplane, according to ExxonMobil. If the particles enter the engine, at sizes smaller than 5 microns, they pose no threat to the engine. Even with the contaminants, the oil is well within industry specifications, ExxonMobil reports, and causes no safety or maintenance issues.
Oil affected by the sediment is in quart bottles with the following lot number printed on the bottles: 002933K4132050 and Fill Code P020430B.
ExxonMobil officials say the metal in the oil will not affect results of oil analysis that some owners do as part of routine engine trend monitoring. To prevent any chance of future contamination, ExxonMobil has implemented changes to its manufacturing processes and has added an additional filtering step to all of its aviation oils.
Anyone owning the affected oil is asked to call AOPA's Technical Services department at 800/USA-AOPA. Those who do not wish to use the affected oil may return it to an ExxonMobil distributor. For a list of distributors, see ExxonMobil's Web site or call ExxonMobil Lubricants at 800/44-Exxon.