[flash]

over the years i have noticed that if i drive the car consistently, very little oil is used. but, if i let it sit for a few weeks, it would use some oil in the first couple hundred miles, and then taper off.



as a part of the development of the supercharger, it looks like i may have buggered my oil rings. i am using a LOT of oil. i have tried a few things, including changing out the head and the air/oil separator, as well as a few treatments designed to clean out the rings so they can re-seat. so far, i continue to burn oil at a disturbing rate.



but, i am not driving the car much either.



this got me wondering if it is just a case of needing to drive it a lot to seat things, or if i really do need to change the rings.



so, i was wondering how much oil others go through after letting the car sit for EXTENDED PERIODS.



please, let's not muddy things up though by talking about what oil, or normal consumption reports, or what is "acceptable". i'm just looking to see a survey of how much oil is used after an extended sitting period

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[94SilverCab]

I think the poll needs to quantify how much oil over how many miles...In my case, if the car sits for 3 weeks it could easily burn a 1/2 to 1 Qt. in the next 500 miles. I drive so rarely that I check my oil after almost every drive and top it off. Doing this results in very little each time (on the order of 2 oz./50 Miles = 1 Qt every 800 miles), that would be an HUGE amount in my DD.



I do find that the longer my car sits the more it tends to use oil.



Jay

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[robadams56]

I try to drive mine at least once a week (including a few miles at highway speed) and so far no appreciable oil consumption.

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[Cloud9...68]

Hmmm. I've never heard of this phenomenon before (which doesn't necessarily mean anything). Flash - obvious question - how's your compression? You have commented previously on your marvelously high numbers. Any change here?

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[Lear35A]

Compression readings won't tell you anything about rings not seating. The passive oil on the cylinder walls will seal enough to give you a good compression reading.

I have this exact problem in a couple of cylinders in my plane. I have done extensive research to see if it's possible to get rings to reseat once the cylinder walls have become glazed or the rings weak, and the answer comes back NO. This means the only solution is to hone the cylinder walls and put in a new set of rings.



Oil can be lost by a leak, coming down the valve guides or bad rings allowing the crankcase to become pressurized. A leak you should see on the floor. Worn guides would lead to a smokey exhaust and/or an oily feel inside the tailpipe. You might also notice oil on the spark plugs. If the crankcase becomes pressurized, the oil blown out would get pulled into the intake system, get burned in the combustion process and go out the tailpipe and get on the plugs.



I didn't answer the poll because I don't know. However, sitting around does no mechanical device any good. We've got to drive these suckas!

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[bombfactory]

Fraid I can't help you on this one Flash. The majority of my oil consumption is due to leaks. I keep a quart back in the cubby at all times.

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[rxter]

Maybe 1 quart between changes - 4000 milesish. I put about 7K miles on last year.

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[Porsche Steve]

Great topic... I find it doesn't much matter on my car as it consistently burns about a quart every 200-300 miles. I've only got 66k miles on the car and have changed out the valve seals but with no improvement. I fear the next step is rings but I'm afraid the cost may exceed the value of the car. Car sat for years and prior owner rarely drove it so perhaps this is part of the problem. I'd be very interested in any potentially easier solutions besides rings!

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[flash]

rxter - unless something new has happened, you don't let your car sit for extended periods, so not a valid part of this poll. sorry.

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[daly]

I went from daily driver to once or twice every other week and see no oil useage change, very little oil used maybe 1/8th of a quart every 3,000 miles.

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[ds968]

When my car was a daily driver, it used about a quart every 1000 -1500 mil, IIRC. For the last couple of years I have been driving it only on weekends and the oil consumption is still the same. Not sure if sitting only five days between drives fits the " a while " criteria

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[flash]

yeah - i'm looking for people with at least 3-4 weeks between drives.

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[gbarrier]

I had the same results with 2 944s and 2 968s. All four were changed from dino oil to synthetic and they sucked a quart in the first hundred miles and another in the next 500 or so before they quit. After that the 968 tip went 10K before it hit the add mark and I changed it. That was however when I was driving the car about 25K a year. Later I added a 944 rag for the daily drive and a manual 968. Then the tip was only driven about once a month and yes the oil consumption went up. I'm guessing a quart or more per thousand. Does anyone know why.

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[Scott Collins]

Just added .5 quart, full synthetic 10W-40 after 1,417 miles. That's when the rebuilt head went on the car, along with all fresh fluids and filters, etc. It sat on jack stands in my driveway for 3 weeks during the project, including the few days when hurricane Irene blew through. That's the longest she has sat, but I'm not sure my situation is really applicable since there were no fluids of any kind in the car (except trans, brake, and p\s fluid).



Anyway, during this 1,417 miles of driving since the project, the car did three trips of 120+ miles. The rest of the miles is daily stuff of 10-15 miles per day, with plenty of starting and stopping, with quite a few 2nd gear pulls to 6k rpm. I actually notice the oil consumption most after long trips, but I believe that Porsche says it's normal for these cars to consume a certain amount, which I figure is precisely the same amount as my car consumes.

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[PorscheG96]

Interesting topic. I've only driven my 968 about 1500 miles in the past yr or so, starting it once every month or two and driving a couple hundred miles at a time. I thought there was a serious problem with my engine because it's been losing 1 qt of oil after only 300 miles. I have a small oil leak from the front engine seals but nothing dripping onto the ground as well as the valve cover seals but the rest of the engine appears to be dry. I've never seen any oil smoke from the tail pipe either [including cold starts and hard accelerations] so I'm stumped. When I had a compression check on my engine the results were 200psi across all 4 cylinders and the car only has 53.5k miles. Current oil is Swepco Synthetic which I've also thought about changing to a different oil...my next step was going to be a leakdown test.

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[PorscheG96]

Well, compression and leak down tests didn't reveal anything so I guess the next step is to pull the head and look for scoring in the cyinder walls or bad valve guides. This stinks.

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[94SilverCab]

PorscheG96, I think your car sounds perfectly normal, perhaps even better than most...why are you pulling the head?



Jay

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[PorscheG96]

1 qt oil consumption every 300 miles isn't normal <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />

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[Porsche Steve]

PorscheG96: I'm very interested to find out what you discover since I've got a similar problem with a low milage car... Near term, I've just been adding oil but I know I have to eventually do something about my oil consumption problem. Best of luck, and perhaps it's something very basic???

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[flash]

any smoke?

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