While synthetic oils tend to be molecules of the same length, density, or whatever crude oil is 'cracked' (separated by gravity) into groups of similar molecules that are a blend to some extent in each general category. Heavies become diesel grades, lighter are kero, gas, etc. (source: API)
I drained nasty old gas from a tractor into milk jugs and capped them for disposal. Just as the fizz can dissipate from a plastic soda bottle over time (months) there has been a smell of ether near the jug. I guess it's smaller moleculeswithin the 'blend' can seep thru' the HDPE just as CO2 seeps thru the clear stuff and alter the formula. So, what if the old diesel has lost some lighter components of its blend and rendered it to a lower grade, not thick 'bunker', but say '#3' or so over the years. I doubt sulphur would be the first to be lost, & apparently it's a non-issue here.(?) Sorry to mention fuel, again ...
Could there be something amiss with digital controls somewhere, as when an auto ECM/EEPROM is mismatched to the vehicle, or the install, and needs to be checked out on a high-end analyzer? (Wrong/defective chip, etc) I was taught in college that 'proper diagnosis is the direct way to the right fix'. There are just so many thinks to check out here and we seem to be spinning our wheels to this point. :mur:
Trying not to over-think the possibilities Fred, honest.
