Number54

Since I bought my car a year ago, it has always shown the max level when performing the ECU oil level check.

I also see a bit of oil under the car, even though RMS was done just before purchase. Could that be related to overfilled oil?

And like an idiot, I removed 9 quarts of oil and filled back 9 quarts yesterday, without thinking about it. Again, the ECU oil level check shows max.

Should I remove some oil? How? What's the impact of overfilling?

By the way, I find the warnings about oil dumping from the oil tank somewhat exaggerated. It does come out fast, but it was not splashy or anything. I did the change in a pit for the first time, really pleasant experience when compared with jack stands.

Thanks.

ninerguru

You can carefully loosen the plug from the case, just enough to get a very small stream. Use the loose plug as a stopper. Put a measuring cup of some type underneath to measure how much to remove... It's like Mission Impossible, but doable. I have done it in the past... Hope it works. Lou

SH || NC

Are you sure its overfilled?

Oil change with filter is 9.6 quarts, according to the OM (p.185). I would get it nice and hot for 20-30min, then check it. The manual also states that after gas and water burn off, the level will read lower. HTH

CT03911

I never put more than 9 in. It always shows full. I think you are okay there and doubt the leak has anything to do with "overfill". If you want to be sure try to drain a half quart out and see if the reading at least goes down a bar.
This would be a very messy procedure but it's not like the engine will seize from being down 1/2 or a full quart. Do it in steps.
Sounds to me like you just have a leaky RMS.

philooo

I have been able to remove excess oil from my 996, by simply putting a plastic tube in the filler tube and extract it with a syringe. A bit time consuming unless you have a big syringe but a lot cleaner than removing the drain plug I bet.

enthusiast

This works. Overfilling is bad.

I drain the engine oil for 60 minutes and then put in 8.75 quarts. Drive the car and top off carefully as needed.

Number54

Thanks guys. I bought a big (huge) syringe, but unfortunately the tube was about 1 inch too short (by comparing the length against the dipstick). I'll be picking up some tubing this week to do the extraction.

@philooo: There is a cylinder inside the oil filler tube for the dipstick. It was so narrow that I was putting my syringe tube "above" it. Is that what you did?

@enthusiast: Overfilling is bad. I've heard this before. Do you know why, or what the effects are?

Thanks.

cfjan

Overfill is bad for car w/ oil sump but is it really a big deal for our engines? I mean, it is dry sump.. the issue with regular engine (non-dry sump) and overfill is that the oil level is too high and all the moving part is stiring up too much oil and make it foamy (oil get aerated) and that's not good for protection. So this issue does not really affect our engine.

Or my assumption is incorrect?

Targatoo

I have the same questions. My indy shop changed my oil for me in the fall, right before storage. Checked my oil last week and found it to be off the scale, even when engine is at operating temperature. I haven't checked the dipstick at operating temperature, but it was about 1/8 inch over the max when cold.

I asked my local Porsche dealer and they said not to worry, it would burn off.

I'm a little sceptical. What is the rationale for avoiding over-filling?

996 Targa

RJFabCab

As others have mentioned, I would just loosen the crank case plug and drain out what you need.

If you had a siphon hand pump with tubing long enough, you could probably suck it out of the tank via the filler tube. But heck, just use the drain plug!

The external tank is only so big. If you overfill, the oil has to go somewhere... and aside from pressure problems, the oil probably could back out the filler tube from the tank or have a major burp off mess from the two foam lines that come off the top of the tank and feed back in at the throttle body.

Number54

Well, equipped with 1m of super-bendy tubing with 7mm OD, I failed.

The tube simply jams at about dipstick length

So I guess it's crank case drain time. Since i just replaced the washer a week ago doing the oil change, do I need another for this?

Thanks.

chsu74

Replace the oil filter with a new one. They suck up 1/2 qt of oil. Its easy and cheap.

911SLOW

from workshop manual:

Oil change quantity without filter
8.75 l

Oil change quantity with filter
9 l

philooo

I have to say that I did this one my 'regular 996' not gt3, so there might be a difference.

In my case, I did feel like the tube was hitting something in there and I was definitely not hitting the bottom of oil pan, but it was deep enough for me to suck a good amount of overfill.

You might want to try a thinner tube.

But again ,there might be a little something special to the GT3

Targatoo

great tip. thanks!