1987 Porsche 924S road trip, oil consumption @100MPH

fpporsche924S · 06-08-2020, 03:57 PM

Hello all, First, thank you for letting me lurk and also for answering my past questions. I bought my 1987 924S last summer and have done maintenance on her, all the seals I can reach, belts, hoses, engine mounts, misc switches, etc. Thanks to this board for helping with some gnarly problems along the way!

My son and I went on a road trip yesterday to visit some family. We traveled from Cleveland to the south of Pittsburgh on nearly all highway miles. The trip went well from beginning to end. I "topped" off with fuel on the turnpike on the way there (I say "topped" because I made the mistake of filling it to the brim once and it smelled like gas for a week after, now it's just shy of full...) Traffic was normal, truck traffic was light, it was a great day to drive, with temp in the 70's. For those interested, the temp gauge was alternating between the halfway line (if I kept it at 60-70) and just at the last line, or slightly over the last line if I was going faster. The speed limit is 70ish.

She started right up in the driveway to make our way home, we stopped for gas again before hitting I79 and headed north. Hitting the turnpike on the way home was actually pleasant, traffic was extremely light... and if you know that neck of the woods, it's three wide lanes, flat and open. With little effort and following some lead-footed folks, I managed to cruise at around 100 MPH for some time. It was glorious, she was as smooth at 100 as she was at 60, amazing driving.

QUESTION - After that 300-mile cannonball (about 4:45 of driving 300 miles), I used this (see photo) much oil - it was slightly below the "full" line. Assuming 100 MPH for 15-20 minutes on a 300-mile roundtrip, what's the normal/average oil consumption?

Thank you all in advance!

v2rocket_aka944 · 06-08-2020, 04:08 PM

1) spec is to check the oil 15 minutes after shutting down a warm engine, did you do that or pull the stick right after shutdown?
2) 100mph is what, 4000+ rpm? for 15+ minutes straight, with a wide throttle opening? yeah it'll eat some oil.

curtisr · curtisr's Garage

Per the manuals, allowable oil consumption is 1.5L per 1000 km (or 1.6 quarts per 600 miles).

fpporsche924S · 06-08-2020, 05:09 PM

Thanks for the replies, yes that was the dipstick still warm about 15-20 min after driving into the garage. Thank you for the oil consumption spec, that helps. And yes, just over 4,000 rpm, I would say not quite floored but close. Thanks!

v2rocket_aka944 · 06-09-2020, 04:16 AM

i bet the engine runs fantastic after coughing out all the junk in the pipes and running wide open for a while.

several of my cars have responded well doing that once in a while.