Three 0W-20 VOAs - Mobil 1 ESP X2, Motul Specific 508, and Ravenol VSE

[SureshR]

My understanding later in life, is the formulations of original synthetic oils were mostly esters, which led to problems, especially related to seal shrinkage. This wasn't limited to Mobil 1, but since it was the recommended oil for vettes, and no doubt Mobil 1 easily outsold Amsoil during this time frame, it was what I saw and came to believe... Mobil 1 isn't any good. Data now shows their oils, especially the ESP stuff, are some of the best, and readily available at unbelievable low prices where you can get a gallon jug at WallyWorld for $25-$28 dollars. One reason they can do this because they own the plants making the GTL base stock and also, in a partnership with Shell, own the major additive company Infineum.

Eh. More like synthetic oils are higher PAO content, which are absolutely neutral to seals. So if an oil seal is already sort of worn and cracked so that it sweats oil a bit, you can switch to a higher ester content oil (aka dino juice conventional) and that would cause the seals to soften and swell up, minimising the leak. Or pour in one of those Rislone, Bar's Leaks, STP type oil additives that are basically concentrated ester, at a quart to four or five quarts of oil, and get yourself an expensive way of converting your full synthetic to something closer to dino juice base stocks.

Of course, if your seals are already worn enough to leave pools of oil under the vehicle, you're better off disassembling the engine and replacing the seals and gaskets.