Did you post this here but in another thread too ?? Seems it's the second time I've seen it and the first time I let it pass but the second .......
I've seen engine problems where so much fuel is dumped into the exhaust the cat is glowing red and most likely melted or close to it and the engine would have kept running right up to the point of the cat substrate melting and plugging the exhaust. Bad plugs, shorting wires or acrhing inside or outside of the cap can all be problems that pour raw fuel into the exhaust. I don't think the Volvo's downstream o2 sensor will tell the computer to shut down.
I work on cars at home and it's common to start and move a car 20 feet and shut it off and them have to move it again in a couple minutes as I don't have much room. Never had the type of problem your post refers to including at work where all mechanics start and shuffle cars around daily.
Why do you think Mobil 1 synthetic oil is any thinner than any other synthetic oil of the same weight, straight or multi ?? The whole reason there are different weights is they are designed different. A 10 W 30 conventional oil of any brand should be the same viscosity (thinness) as a synthetic blended oil of any manufacturer as a pure synthetic of any manufacturer including Mobil 1. They are all the same thinness or thickness if the weight(s) is the same.
The lifters in our engines adjust themselves by using oil pressure to "pump up" (get physically longer) and automatically adjust. When the engine is shut down the oil pressure drops and the oil drains to the pan and the lifters can't expand to hold the valves open. Unless Volvo is drastically different under that valve cover all hydraulic lifters work the same way. Lifters can stick and in that case a valve could possibly be held open but it would be one that stuck affecting one cylinder and it would still start it would just be unbalanced when running due to the dead cylinder.
If the valve is stuck open how is oil squirted into the cylinder supposed to "seal" the valve against the compression built when the piston comes up to TDC??
It takes 20 minutes at 3,000 RPM for the oil to reach all the "places". Every oil change I do I've never run an engine on high idle( higher than high idle actually), sitting still to circulate the oil before driving. Has anyone actually done this ?? I pour oil into the filter before I screw the new one on just to make sure I get pressure as soon as I can and I'd never think of running an engine at that high RPM for 20 minutes right after an oil change. I wouldn't run it at at that RPM for any reason for 20 minutes.
Now the reason I passed it over the first time is I was recently burnt telling someone all cars have a high and low side service port to the AC systems and up till this Volvo I've always had both ports to hook up my manifold gauges to. Cars, pickups and large trucks but NOT on a Volvo, low side only when I went to look.
Soooo, I may have missed something in my research on Volvo's and I'm going off what I know from everything else but if you're going to post something to try and be helpful you should at least understand what you're posting. I could be wrong but I don't find anything I agree with here.