Wayne Smith

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
[/QUOTE]

Starting a cold car and letting the rich mixture flow onto the cats for any extended time of idle doesn't sound like good advice. It goes against so much that has been discussed in this Forum and others.

2010 C4S ... I just completed my 15th oil change ... 3 years 4 months, 72K miles (107K total), change about every 5K miles. I jack the back end a bit higher than the front so the oil flows toward the drain. With every change I've drained just over 7.5 quarts (1 hour up to overnight drain time), added 7.5 quarts, end up one bar above the bottom (just below half), add a cup to get the second full bar lit, and leave it there to insure that it is not over filled. I've never needed more oil than that.

ADias

No reason to fill to the top bar as that risks over-filling. 1 or 2 bars down from the top is the sensible way.

Bruce In Philly

I find it amazing that we have the same cars and we take different amounts of oil. That is stupid... er um... weird. So am I overfilling? My gauge appears to operate well watching slowly go down as the miles go on..... I just get some odd readings after a change.

As an aside, these dealer techs are not experts..... they are not Porsche engineers and sometimes I think their knowledge is no better/worse than just an old timer with experience. Doesn't mean they are correct but they have a system that works for them.

Peace
Bruce in Philly

dgjks6

I find it weird that I have the same car and do the same oil change the same way every time and need different amount of oil each time. FWIW I have the same issue on the Macan.

I put 6100 miles between changes this time. Maybe if you change at 5000 miles you only need 8 quarts and at 6000 miles you need 9

Bruce In Philly

Good! So if we go with .5 litre cold to hot...... ADias: this appears similar to your experience also. I can see why Porsche wants you to measure hot (although I have trouble believing a .5 overfill would blow up our engines). But this does not explain the 1 or 1.5 liter differences of drain-to-fill in some of our cars. A new oil sensor for a 997.2 is about $110 (or $70 for a Hella unit)...... Hmmmm........ 997.2 and .2 sensors are different and very easy to change out on a .2... it is right next to the drain plug.... pops straight up and in.

FYI: I think Hella may be the MFGr of our oil sensors but I am not sure..... in digging around, I found that the Hella sensors not only measure fill level, but tempurature also. I wonder if Porsche is using this... I suspect they are.

http://www.hella.com/microsite-elect...ensor-385.html


Peace
Bruce in Philly

bhvrdr

I agree with you Bruce. I did mine and refilled with 8 quarts. I then measured the car warm and display showed 2 bars from full. I added a total of about .75 qt to get it full. Porsche recommends on the 997.1 for it to be filled to max so I fill it to max. I agree that even if you overfilled 1/2 quart you arent going to be submerging the crank so I dont see an issue. I'm more worried about oil starvation from being down on oil.

Mike

Wayne Smith

There is an elephant in the room. One step in the oil change on the dealer list is oil level sensor calibration. This has been brought up in previous posts but there were no conclusions or definitions of what this step actually was.

So some random thoughts ...

Various calibrations could be a factor in the different amounts of oil that we think we need to add, and thus affect the amount we remove.

As far as oil out vs oil in ... water accumulation and oil burn (loss) could be variables as well.

We know that we aren't removing all of the oil when we drain, so we shouldn't expect to add the entire factory spec oil volume when we fill.

As far as measurements go, if volume increases a half quart during warm up, that seems like a major adjustment to readings. I've read in track prep that you should run your oil on the low side. With oil temps getting 50 to 75 F warmer than usual under severe driving conditions, it seems like volume could increase a quart and a low fill would be good advice.

My experience is on the .2 (with scavenging pumps in the sump) and may not apply to the .1.

evo9

IMHO - This thread would not be this long if brilliant Porsche engineers had found a way to use/integrate a 'physical dipstick' in these engines.... I'm just sayin... :-) Only providing electronic gauges with their fallible senders for reading engin oil level seems, should I dare say, "unwise".

pEacE oUT

Charles Navarro

Running the oil level to the max, especially on the track, is a recipe for disaster. If you are concerned about starvation, run a race oil and put a deep sump on the car. You should run the oil level at the min fill to accomodate for expansion. This also reduces the crankcase windage which in turn reduces the aeration of the oil and load on the AOS.

I always recommend to run the oil level cold at the min fill mark and only add oil when the car is cold and has been sitting overnight on a flat surface.

I've lost track of the number of people that have caused their own consumption symptoms by continually overfilling the engine.

slicky rick

ADias

This thread could not get any better expert contribution than this one from LN Engineering's principal.

Follow Navarro's advice and do not overfill your sumps.

JCGMS

One other thing to remember is the different capacities for S vs Non-S engines.

From my 997.1 manual:
911 Carrera, 911 Carrera 4, 911 Targa 4: Oil change quantity without oil filter approx. 8.5 quarts / 8.0 liters
911 Carrera, 911 Carrera 4, 911 Targa 4: Oil change quantity with oil filter approx. 8.7 quarts / 8.25 liters
911 Carrera S, 911 Carrera 4S, 911 Targa 4S: Oil change quantity without oil filter approx. 8.7 quarts / 8.25 liters
911 Carrera S, 911 Carrera 4S, 911 Targa 4S: Oil change quantity with oil filter approx. 9.0 quarts / 8.5 liters

My 997.1 C2 takes about 7.7 LITERS to get to one bar below max after a drain of at least 1 hour.

Big Swole

Oh I'm 100% clear what the oil pump is capable of and never questioned it taking 5-10 minutes to circulate the oil enough to check. I just meant to get it up to temp and thin it out a bit so it would drain back down quickly for a level check.

Petza914

In reading through the input here, my 2 cents.

In oil threads such as these, contributors need to differentiate between the .1 series cars and the .2 series cars, as jhbrennan stated, the .2s are checked warn and as Charles (LN) recommended, the .1s should be checked cold first thing in the morning. Also, if you get an odd reading, don't assume it's a correct one - check it again. In my .1 cars, I can get a false reading of 2 lines down and without ever starting the motor, but cycling the key for the oil level check again, can get a completely normal and full reading (half a line down) and then get this same repeated reading for a couple more key cycles. If I took the first reading as gospel, and added .4-.8L I'd potentially be that much overfull, and that is enough too much to prematurely damage your AOS.

Remember, a line or 2 down is exponentially better than overfull

As Wayne says, idling a 997 for 10 minutes upon first start with cold oil during the enriched warm-up phase is one of the worst things you can do to your 997 due to cylinder wall washing from the enriched mixture. Driving the car during this phase burns off the additional fuel because of the increased load on the motor from driving the car. It's even worse to do this in a .1 car as not only do you get the wall washing, but the load on the IMS bearing is highest at idle speed since the bearing internals are rotating so slowly. At higher RPMs, the centrifugal force of the bearing spinning helps to spread the load across the bearing races more evenly and the bearing more self-centers instead of the load of the shaft transferring to the ***** and riding on the races.

On my stock 2005 997.1 C2S after an extended drain interval (at least an hour), prefilling the filter and adding a total of 8 quarts (this includes the volume in the filter) gets me onto the gauge (2 lines down from full). I then monitor this with a check first thing the next morning - if it still shows 2 lines down on more than one sequential reading, I add 0.25 quarts and then check it again the next morning. At this point, before adding any additional oil, I'll look for two mornings in a row of the same reading and if still a line down, will add 0.25 quarts again. Even if it still shows a line down after that, that's where I consider it full to account for errors in the electronic gauge and or thermal expansion of the oil. I never check it after driving the car, like after a lunch or gas stop, even if the countdown timer allows the check to run - first thing in the morning checks inside the flat garage are the only ones I base any decisions about whether to add any oil on.

Monster231

Are you guys taking oil consumption into the equation? My car burns anywhere between .5 - 1 quart every 3000 ish miles which is about how often I change my oil