Burning through 1/3 of oil over 5k miles

[patssle]

Well after a year of ownership and about to do my second oil change...I finally got a good count on oil consumption as I wasn't keeping tracking the first 5k miles.

I've burned through about 3 quarts of Mobile1 0w40 oil over the past 5000 miles. No drips or leaks - my garage floor and work spot are both clean. This 2000 S was a garage queen with 45k miles when I rescued her 1 year ago and had very little miles put on her over the last couple years of previous ownership. I run her hard when I can but let her warm up properly and without idling. Filled to and kept at halfway on the digital meter. My first 5k miles I used 15w50 oil and I don't believe it burned as much (but no accurate usage tracking was done) - so either it's getting worse or the thicker oil makes a difference. Will switch back to 15w50 for summer driving.

What do you guys think...burning oil isn't normal for Boxsters it seems. Am I going to have an engine failure at some point? Are the rings probably bad from sitting for so long and cracked? Or something else?

[The Radium King]

I think you are well within factory specs. I see similar consumption. I do a lot of long trips in my car and have the opportunity to track and compare changes. no oil on floor (ie, some weeps from the rms after a day at the track but nothing that actually hits the ground). changed the aos to see if it was getting by there but no change to consumption. no change with different weights of oil. got compression tests and results were equal on all cyls.

conclusion? probably aos still, letting a few table spoons by here, a few tablespoons there ...

[rfuerst911sc]

It wouldn't hurt to switch brands of oil to see if any changes. Not my intention to start an oil thread just a suggestion.

[Jager]

Check your AOS.

[patssle]

Hmm I've been considering getting a new AOS just as preventive maintenance....I don't think the PO ever put a new one in.

[Jager]

While the motor is running (and warmed-up) remove the oil fill cap. If you have a lot of suction (like a shop vac) at the oil fill and the motor struggles and almost dies, you have a bad AOS.

[runjmc2]

Leak at spark plug tubes that burns up prior to hitting the ground? I don't think 3 Qts in 5K miles if normal…a good thread in the past showed most do not add any oil between oil changes.

[kk2002s]

3 qrts in 5k miles, that can't be good.
If it isn't a leak then it has be getting burned or else someone is siphoning it out.
Are you seeing oil residue around the tail pipe, back of the car.
When do you realize the shortage, at oil change or are you pulling the dip stick and checking regularly?
Is 5k mile change for you 6 months?

My 02-S with 67k miles, maybe I top off 1/8 qtr between its 5-6k mile (6 month) changes and I am starting to see that I need to replace Plug tubes as there is evidence of that
So to others, would a bad AOS start pulling more oil and send it in to be burned - Or is it that a bad AOS creates more vacuum that sucks more oil into combustion?

[Trey T]

+2 on the AOS check of oil residue along the line into the manifold

[landrovered]

My intermediate shaft was full of oil when I changed the IMSB. It will hold about two liters.

[smshirk]

I use about the same amount in 5k. The first 1k it barely drops on the stick, then uses a little less than a quart every 1k until changed at 5. It uses about the same every 1k miles after the first thousand, every time. I haven't noticed any difference when driven hard VS stop and go rush hour driving. Some motors burn oil and some don't. It seems like I remember Porsche used to say anything less than a quart every 600 miles is normal, although a quart every 600 seems excessive to me, it doesn't hurt anything but your wallet as long as it's not smoking, or has performance problems. That 600 mile thing was for air cooled cars so they may well have changed their direction on the water pumpers, but if all else is good, and it didn't just start using oil after years of not using any, I wouldn't worry about it

[patssle]

I haven't gotten to look at the AOS yet but I did take off the oil cap and the engine did bog down just a little, but it didn't sound like it was ready to die. There was some suction as well.

The PO did in fact change the AOS 5 years ago and it has 16,000 miles on it (I love Porsche owners and their meticulous records!). Do they die that soon???