Oil was changed at 5hrs 25hrs with straight oil then at 50hrs with
W80 then at 100hrs with Exxon then every 50hrs.
Then in the last 10 hrs, due to the small oil leak 1 ltr was being added every 2 hours.
Found after 140hrs on Exxon. Thinning not noticed as this oil is expected to be a little thinner, at lower temeratures and be a little blacker in operation. Due to the high detergent action.
Exxon Mobile had to withdraw full synthetic oil, AV1 fast due to engine damage. Did not carry the lead salts very well, due to the high piston blow by in aviation engines. Shell did warn them about this, but they ignored it. Thats why Shell never produced a full synthetic aviation oil.
Car engines have closer tolerances, better oil scrapper rings and run on unleaded fuel, so far lower lead salt load and Mobile 1 works very well. Not so good in older classic cars, its to thin.
Of course Exxon would say their oil is wonderfull, but they did ship a lot with very fine iron particles in it, from a pump impeller breaking up in the refinery, not great quality control.
So if you have a grey sludge left in the bottom of you oil containers, thats what it is. Supposed to be fixed now.
I believe they have only lab tested this oil with a minimum of field testing, not good. Even their supposed cam wear test is not a realworld situation, as most wear happens at startup not running.
I would monitor an engine very closely running on this oil, as several engine overhaulers are reporting higher wear and lower time to TBO, on engine cores being returned, that have run on semi-synthetics, but strangley no one mentions any oil companies. They don't want to be sued
Horizon Flyer