Low Oil - Lasting Damage?

"TheScullster" gurgled happily, sounding much like they were saying:

It's not a low oil LEVEL light, it's a low oil PRESSURE light.

As in virtually zero oil pressure - the reason it comes on with low level is because the pickup and pump are sucking air...

Was that the oil pressure light, or oil level one? Some cars have both. If it were the pressure one it means no oil was getting to the bearings, etc, for a brief period.

Should be ok, then.

No effect on fuel economy. Air con does, though.

Both my SD1 and BMW have a low oil level warning light. As well as an oil pressure one.

I had an old Bentley once which obviously had some form of float sensor in the sump - press a button beside the fuel gauge and it read actual oil level, rather than just a warning when too low.

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "TheScullster" saying something like:

Briefly, no. It depends on how much stress was on the bearings at the time. Otoh, I had a mate who tended to only top up his bike engine when the light flashed - he thought it was a level warning, but his bike didn't have one. Amazingly, it kept running fine.

Don't bikes generally have roller bearings so a bit more tolerant of a short time without oil?

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Dave Plowman (News)" saying something like:

Many of them did (still do) at that time, but his didn't.

Roller bearing big ends and mains commonly run with 5psi oil pressure, and I believe a RB would have got away with it, for longer. Still a daft thing to do, of course.

Conversely, some of them rely almost 100% on oil for cooling.

Chris

I had an old air-cooled VW in the 70s, and I never checked the oil, just put some in when the oil light started to flash going round corners. I did that for 3 years, no probs.

The OP won't have hurt his engine, no oil pressure doesn't mean no oil in the bearings. Although prolonged use like that would not be a good idea.

Steve

There are other issues with running oil so low that it gets below the pickup level causing the pressure to drop and the light to flash. Most cars don't have an oil cooler, so the quantity of oil helps prevent overheating. A small amount of oil in circulation will also break down more quickly than the correct amount. May not be as much of a problem on an ancient design using modern oils - but may well be on a more recent one.

I know. But doing this once isn't likely to have caused lasting damage, which was the OP's question.

Steve

I got the impression it wasn't just once. ;-)

From the OP -

Does it do any lasting damage, running with a low oil level? Our Mazda 6 ran low enough on oil recently for the oil light to flash on once.

Steve

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "shazzbat" saying something like:

An old cooking VW lump likely has less load on the bearings.

It means the pressurised wedge of oil has gone. Metal-to-metal isn't far away.

Indeed. He'd been doing it for a while before I noticed.

They also rely on the same oil to lubricate the gearbox

Indeed, as do some cars of course.

Chris

I dont know of any car that also runs a wet clutch though

Interesting; I'd guess there is one though!

Chris

Anything with a BW dualtronic.

I'm guessing the OP meant a car with a wet clutch that also used engine oil to lubricate the transmission, like many motorcycles.

Chris