I'm gonna go straight ahead and self-identify as an idiot.

With that out of the way, my oil measuring gauge showed engine oil to be at the minimum mark today (B in the image below) so I went and got me some Mobil 1 5W-40 to top off before my first oil change is due in a month or 2500 miles (I'm at 7500 mi).

I read the instructions and took a mental note that the difference between min and max is "about 1.7l". Bummer is I grew up with the metric system and didn't realize that the two quarts I poured in were more than 1.7l. Instead, I somehow equated a quart with a line on the gauge -- i guess because the engine kind of looks like a gallon jug of milk and the difference between min and max consists of 4 segments...

Well, now the warning light about oil overfill is on and the gauge looks like D in the image below.



I've read threads here on oil overfill for a number of older models, all of which suggested to drain the engine. Any suggestions regarding what to do with a 991? Do I need to bring it in to a dealer/mechanic or could I e.g. get a clean hose and siphon some oil out through the oil filler opening?

Also, the overfill is at most 0.2 quarts, which seems not much at all. Nevertheless, I didn't drive the car and decided to find out what to do instead.

 

lol ive seen it happen before.

 

Call dealership (workshop)

 

how about open up the oil filter
and remove some of the oil present inside the housing?...

 

First of all, I believe that you should be using Mobile 1 0W-40, not 5W-40. The latter does not meet Porsche specs the last time I checked. As for the overfill, I'd quickly remove and replace the drain bolt while the oil is at ambient temp. Then recheck and add oil as necessary.

Spyder

 

Drain a little while cold and retest like Spyder suggests.

ChuckJ

 

What about using an oil extractor to pull some out without messing with the drain plug?

Can you use an extractor on these engines? This is my first 911, so I haven't done it myself.

 

Thanks to all for the replies!

It seemed to me there were 5 potential solutions, in order of increasing cost/effort:

1. Siphon oil off through the oil filler opening. I've read reports from others that this works on older 911 models through the dipstick tube. I actually tried this today, even though there is no dipstick on the 991, but I am sad to report that it's a no-go. The tube is long and winds around quite a bit and the service advisor mentioned that there is no oil pan at the end (or something to that effect). There might also be a filter somewhere in the tube, I don't even know. Bottom line is, my hose came back out without ever hitting any oil.
2. gracious_911's suggestion to open the oil filter. I didn't try that one because I have neither a 36mm nut tool nor a torque wrench (to close it again to 25Nm) nor a replacement gasket.
3. Drain a bit of oil as TSpyder and ChuckJ suggested. I was tempted to try this, but again, while I probably have an 8mm Allen key somewhere, I have neither ramps or jacks to raise the car nor a torque allen wrench to close the drain bolt back up to 50Nm. Also, it seems one is supposed to replace the sealing ring there, too (which I don't have).
4. Drive slowly to a nearby workshop to drain a bit of the oil. Luckily, there is a family-owned Porsche workshop 3mi from my house. I called the owner and he thought it'd be probably safe to do if it's only 0.2 quarts over max, the engine is cold and I go slowly.
5. I did call the dealership as Fester suggested, and the service advisor suggested flatbedding to the dealership and doing a full oil change.

I wish #1 would have worked or I had the tools for #2 or #3, but short of flatbedding it, it seems #4 is my best choice unless anyone has another idea?

Edit:

I just realized the manual does talk about what to do in case of overfill, see p. 100 (italics by me):

What this seems to suggest to me is that there is a safety margin of sorts since damage depends on "overfill quantity" (among others) and since the overfill should be corrected "at the next opportunity", both of which seem to speak in favor of option #4 above.

Curiously, the manual doesn't mention engine damage here at all, just catalytic converter damage.

 

Nice feedback, chancludo.

ChuckJ

 

Get a hand pump from auto parts store. Pump out some from the oil filler and you should be good. If you remove the oil filter, you will get a mess of oil coming out

 

Good idea,
in any case, if you try to flush from below your self, keep in mind the pressure is enormous and it will create a mess anyway.

Now that I read all responses, if it was me, I would just do the 3 miles to the nearest shop and flush a little. I highly doubt there will be any damage in 3 miles.

 

Just had my oil changed on my 12' 997.2 TTS. It only had 3000 miles on it but was over a year old. The dealer used Mobil 1 5W-40.

 

Yes, forgot to mention that. See manual page 202. Mobils 1 5W-50 is also OK according to the table on that page.

 

0W-40 is labeled as 'european' formula...
not sure what this means...but it is the most 'expensive' from all 3 suggested in the manual...

 

when crankcase is overfilled with oil, the oil can get into the intake and sucked into the intake manifold. this can mess up the mass airflow sensors and cause the engine to stall, not to mention changing the air filter. this has happened on cars overfilled with 2 qts