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Car running upside down

A relative gently turned over in a snowy ND ditch upside down. Left car idling, maybe 5-10 minutes. Does upside-down negate problem of no oil through pump?

Any knowledgeable idea of suspected engine damage at this point?

Nothing but engine off negates the problem of no oil through the pump. This is a gag post isn’t it?

The engine may continue to run with the vehicle upside down (I’ve seen it), but the oil will all run to what would normally be the top of the engine, and the oil pump would be starved, so the bearings would not be getting the proper lubrication.

No, the oil at the top of the engine does not eliminate the problem of no oil through the pump.

It would have been much better to shut the engine off.

Agree; airplanes with piston engines have dry sump lubrication so they can fly upside down. Running a car engine without a steady feed of oil to the bearings for 5 minutes is disastrous, in my opinion. Only the cylinders would be getting sufficient oil since part of the crankcase contents would sit inside the pistons. The valve gear would get some oil, but everything else would be starved. If the oil filler cap fell off, most oil would quickly drain from the engine.

Never seen a car that way running, but have seen the results of a tractor, just on it’s side. The motor was toast and had to be rebuilt. If it was the short side of 5 minutes…who knows. Living on a mountain, I was advised to get a TWO stroke mower for just that reason.

Very likely. The oil pump pulls the oil up through a “pickup tube” the end of which is immersed in the oil. It doesn’t pull all the way at the bottom of the pan, but it pulls from pretty low in the oil pool.

If the engine is a V-style or an Inline style, when flipped over the oil would go up into the cylinders and the open crankshaft area where the crank rotates and away from the pickup tube. It would also begin draining up into the valve cover spaces through the drains through which the oil normally drains down from the valvetran(s) to the crankcase. The oil would also likely get pulled past the rings via the vacuum ing the cylinders and the engine would burn some. Rings have gaps in them to enable the circumference to vary to compensate for thermal expansion and expansion and contraction as they go up and down cylinders which with wear become conical.

Here’s the “if” part. Normall the gearings are suspended in a pressurized oil barrier as the crank turns. Not having this barrier would definitely destroy the bearings if the engine were revved, however I’m unsure whether being drenched and possibly immersed in oil in an upside down engine would allow enough lubrication to protect the bearings st idle for a short time.

If the car is a Subie or a Porsche with horizontally opposed cylinders (“boxer” style") the problem would be similar but the oil might not be as inclined to disappear into the cylinders. It might far okay for a slightly longer period.

This is probably a prank post, probably not, but it’s an interesting theoretical question if you really think it through.

The bearings may be ok. It is surprising how long bearings can last without oil pressure in an idling engine. The bearings don’t go dry the second there is no oil pressure, capillary effect keeps a film of oil in the bearing clearance. The rpm is low and the pistons are compressing a vacuum. Ever see those oil ads where they “prove” how good their oil is by draining the crankcase and the engine survives several minutes of running? What they don’t tell you is that their competitor’s oil would have probably dont the same thing.

What you do need to be concerned about is the possibility of a hydraulic lock from oil leaking past the piston rings and filling the combustion chamber full of incompressible oil. Remove all the spark plugs and let the starter spin the engine for 10 or 15 seconds to let the engine blow out any oil that may be in the cylinders. Fail to do this and you may end up with a bent connecting rod.
This was a common problem in the bottom cylinders of aircraft radial engines.

You would get plenty of oil splashing around to prevent damage to vital things like cranh and rod bearings. There is no load on an idling engine so pure dumb luck will probably save the engine from zero oil pressure.

Thanks for varied comments but maybe more info needed:
It’s a hybrid (Ford Escape or similar), need to talk to her
again for details. (I thought this shut down automatically anyway ie.
at stop signs).
I can’t help but smile thinking of this other than she has limited income and this is very important to her. This would absolutely kill live with her and Click&Clack on air but I think she might want anonymity.
Hey, she was just following safe winter driving tips: don’t panic, stay warm and stay in the vehicle :slight_smile: (ok you can imagine her ‘reasonable’ explanation :slight_smile:

I suspect the crank bearings, the rod bearings, the cylinders, and the camshaft(s) saw plenty of lubrication to survive the ordeal without damage (see my earlier post). Once turned rightside-up the oil under the valvecovers will run to the galleys and drain back through the return passages into the crankcase.

The only real concern will be possible oil in the cylinders. It’s unlikely that enough would have gotten past the rings to hydrolock the engine IMHO, but there would be another path if the oil ran unto the valve cover areas and past the PCV valve. I’d definitely replace the sparkplugs, the air filter, and check the PCV valve and the oil level.

It’s also possible that if some got into the cylinders and got burned it contaminated the oxygen sensor and perhaps even the cat converter, but if that’s true she’ll get a CEL when she gets it running again. Keep these thoughts in mind should that happen.

The reality is that she’s unlikely to have sustained any internal engine damage.

You question on the engine shutting down is a good one. Perhaps somone here is familiar with inertial sensors that should shut the fuel pump down…??? Does this vehicle have one I wonder?