Engine oil Mobil or Shell

I've had my '88 GLI 16V for over 20 years and always used mobil 1 15W50 without issues.

Mobil 1 since day one (first oil change). 5w-30 (as per vehicle spec). 316k+ original owner miles. Virtually no carbon or varnish.

I will say after switching to mobil1 in one of my rigs it cleaned out a hell of a lot of shitty carbon deposits and crap in the valvetrain. Looked nearly new when I pulled the valve cover at 210 thousand miles.

On an old e36, 5w30 full synthetic no matter the brand would often cause some leaks. Switched to some thicker Rotella oil made for diesels and suddenly no more leaks.

I use Mobil 1 because it's the only oil that prevents VVt noise in my NB Miata

I've only used Mobil 1 5w-30 Full synthetic. I think it's the only oil I would ever use. This Mobil 1 oil has simply been the one that I used from the get go, mainly due to recommendations, and it does what it needs to do. I feel confident using the product.

The Toyota mechanic who has a YouTube channel (Car Care Nut) has previously said that Toyota OEM oil is Mobil 1 (with a few exceptions for collaboration cars).

Mobil1 15w-50 (red label) was always good to me, and readily available at wally world. Never had lifter tick in my S50US, on track or otherwise, and it went to 298k before the head gasket gave up. Absolutely could have resealed the engine and ran it another 100k+ (swapped an S54 instead).

I use M1 Extended HM with an stp premium filter. Go about 10-13k between changes.

I'm currently happy with Mobil 1, 15w50, except when it comes time to pay for it, yikes that stuff is pricey. First time I ran the Mobil 1, guess what happened?? Oil light flicker at hot idle. Replaced the low pressure switch, no more flicker. That switch didn't change characteristics just because I changed oil, the fresh oil was thinner, oil pressure decreased.