dgjks6

We have 2 Porsches. A 997 and a Macan. Every time I change the oil I put in the recommended amount and every time the computer may or may not read full. Put in 7.9 quarts on the 997, like always, and now reading at minimum level. Last time did the same and read full.

Just venting. The one advantage of the 996 was a dipstick and cold read in the morning.

jhbrennan

Not sure year and model of your 997 but 997.1 manual says capacity for 997S with filter is 9 quarts - how did you arrive at 7.9 quarts?

cosm3os

You cant get the whole 9 quarts out of the car when you drain.

Bruce In Philly

I get variable results after I fill in my 997.2 S and yes, it bothers me. If I do a really aggressive drain, I can get 9 quarts into the car. By that I mean I jack the car up with two jacks in the rear..... drain.... lower the car... drains some more... tilt the car to the right (or left can't remember) and one tilt will drain more...... after about two hours of canting the car all different ways, you get a heck of alot of oil out of there. I asked the Porsche tech about this when I bumped into him when I was buying a part.....he said if he lets a hot engine drain overnight, he can get 8.5 to 9 quarts into a 997.2 S. Even so, I measure the oil out and always put maybe a half quart less back in (if it was above half full to start). Then drive the car until hot.... then remeasure. Even then I don;t add if it tells me..... next day after another drive I measure..... then I measur again until I get a consistent read. I wonder if my measuring sender is bad..... easy to replace from the oil pan on a 997.2, but that is another story.

Said again, I get variable reads immediately after an oil change. I asked the tech about this also.... he said after a change, start the car and let it idle... go get some coffee.... 5 to 10 minutes of idling... then measure. Sounds pretty stupid to me but that is what he said.

Peace
Bruce in Philly

Big Swole

I don't own a 997 (yet) but why would this be seem stupid? For any car for that matter?
Once filled, let idle to help get oil up to somewhere decent temp and worked throughout the engine, and then check level after sitting turned off for a bit.

dgjks6

Can't check a 997 like that

And my manual says 7.9 quarts. And I put that in before and get a full reading

evo9

2010 C2S here.

Just did an oil change recently, and after letting car sit/drain for 1.5 hours with rear tires driven up on 2x4's, It took 8.5QT for oil level gauge to read full.

Regards,

wm

wc11

For what it's worth I put about a 1/2 litre in the oil filter can as well before screwing back on.
Total is about 8.0 litres or 9 US quarts

jhbrennan

997.1 - oil level checked with engine off
997.2 - oil level checked with engine at idle

Bruce In Philly

Here is why I think it is stupid. Actually, I will be honest and say I don;t understand why.... but it is more entertaining to say "stupid".

The oil pump in our cars is pumping a mass amount of oil fast. In the vid below, it circulates the full amount of oil "4 times a minute at normal speed". While our Porsche engines may not be pumping at that rate, more or less is possible, it still illistrates that a big amount of oil is circulating. I have trouble believing that it takes 5 to 10 minutes to have oil "worked throughout the engine". By that time, something would have blowed up real good. I suspect a few seconds of idling gets the oil everywhere it needs to go. The vid also said another interesting fact: the oil pump will fill a bathtub in three minutes.

Peace
Bruce in Philly

The first part of the vid is stupid so go right to 4:20 where the good stuff starts. Or go directly to 9:44 for a really cool demo where they hook a hose directly to the outflowing part of the pump and let fly with it..... again, 5 minutes to have the oil "stabilize" to me sounds stupid.

ADias

The 10 min idling is to warm up the oil to measure at op temp.

Bruce In Philly

Can one of you engineers tell us how much motor oil's volume changes with temperature? Then we can swag how much the meter on our dash board would change between cold and hot oil.

Peace
Bruce in Philly

mbatarga

Thermal expansion of motor oil example on this page:

https://www.engineeringtoolbox.com/v...ion-d_315.html

Seems to be around 1% for temp increase from 20C to 40C

Based on my calculations, from 70F to 225F, 8 Liters expands to 8.4836, using the 0.00039 factor in the expansion table.

ADias

From my experience with air-cooled engines holding 12qt of oil, I see volume expansion of at least 1/qt (on the dipstick) between 68F and 210F.

dgjks6

Well I added another quart. Drove my daughter around until up to temp. Checked and went to full. So 9 quarts this oil change. 8 last time. So my working theory is every third oil change takes an extra quart.