Freezing weather = low oil?

[jakesmith]

TUrned the 997 on today (didn't start the engine just turned the key to 'on') and oil reading was very low on the computer, despite being a 3.8 it doesn't usually use any oil. It was literally freezing today and car has not been used for a few days and it was -3 last night, could this be the reason? No oil on the driveway.

[Rockster]

jakesmith said:

TUrned the 997 on today (didn't start the engine just turned the key to 'on') and oil reading was very low on the computer, despite being a 3.8 it doesn't usually use any oil. It was literally freezing today and car has not been used for a few days and it was -3 last night, could this be the reason? No oil on the driveway.

Oh yeah, definitely.

My Boxster's oil level can vary by 2 or even 3 bars when checked cold vs. hot. The reading can be low by 3 bars, it depends upon how close the oil level is to being a bar low. If close, then the temperature drop can have the level down 3 bars. It doesn't have to be arctic cold either. The other night it got down to 38F and the oil level was down the 3 bars when I checked the Boxster oil level as is my routine before the 1st start of the day.

Also, be aware if the car is not level this can also affect the reading, too.

[anonymous-user]

Liquids do reduce in volume with low temps but, paradoxically, water starts to expand as it approaches freezing (under 4C). But differences are not that big.
One possibly cause of sudden drop in oil volume is when a car has been driven on lots of short journeys during which water from combustion condenses in oil which never gets warm enough to evaporate it off (tell tale sign is mayo under the filler cap) then taken on a long journey that does.
At least in theory....

[Markbarry1977]

I have a 987.1, I have on occasion done multiple tests in the morning prior to starting the car and got different oil level readings by a bar with the car sat no even started let alone moved. I really wish manufactures would put an old fashioned dip stick on cars. My old 123d had both an electronic gauge and a manual dip stick. For the few extra quid it costs per car I just can understand why both aren't incorporated.

[BertBert]

I thought the bars only worked with hot oil. Or did I dream that?

[Digga]

On the dry-sumped Mezgers, presumably as long as readings are not below 2 bars from max. then that should be plenty enough oil, right? My fear is, trying to 'brim' it, you could easily over-fill, taking expansion into account. Hydraulicing an engine is not good.

[jakesmith]

Just to update this, today is a lot warmer and oil level now reads higher, just above half on the digital scale. Before it was reading about a quarter. The car has been used for a few short runs recently which may explain it. I've had a look through recipts and it uses about a litre every 8,000 so no cause for concern when the handbook suggests up to 1l per 500 miles is ok(!)

[paralla]

The volumetric thermal coefficient of expansion for engine oil is 0.00070 per degree C.

[anonymous-user]

paralla said:

The volumetric thermal coefficient of expansion for engine oil is 0.00070 per degree C.

Bugger all in otherwords
Unreliable gauges then?

[WindyM]

BertBert said:

I thought the bars only worked with hot oil. Or did I dream that?

997 Gen 2 3.8 DFI oil level has to be hot to use digital gauge. You have to remember to check it *after* a hoon before you switch off!