An Unbelievable (For Me) Oil Consumption Story

So I topped up my baby with 10W-40 about six weeks ago. I don't get to take the car out much, because of the fact that I live and work in Manhattan. Maybe a couple of times a week (mostly on the weekend) . So it's been used maybe 12 - 15 times in the last six weeks. This morning I set out for a golf game up North. The drive is about 80 miles each way. The car behaved beautifully on the way there and back. Driving was spirited but not aggressive. A block from home (thank God) on the way back, while pushing off from a traffic light, the car suddenly stalls. I find it odd, since I have not stalled once in the past six weeks, but don't think too much about it. I try to switch the engine back on, but get the warning "OIL TOO LOW / CANNOT START ENGINE" or something along those lines. Through the system diagnostic I note that the oil level is at the bottom tier and blinking. I obviosly immediately shut off the car, walk two avenues to the nearest gas station (again, very fortunate that it was so close), and bought some more 10W-40. Emptied another quart in her, and was on my merry way. System now shows it right at the top marker between the two lines. A couple of thoughts from me: - First, we all grumble and groan about the bugs in today's technology-laden cars, but I can tell you, a diagnostic like this - where the car automatically shuts off if there is too little oil in the vehicle and informs you of such - is a Godsend, and prevented what could have been permanent damage to the engine. - Second, I'm glad it happend on the way back, and a block from my home and two blocks (ok, avenues) from a gas station. It could have been very inconvenient - not to mention highly dangerous - if I this had happened on the two lane Taconic Parkway (where there is no shoulder) or the Major Deegan. - Third, it is my own fault for not checking the diagnostic on the level of oil before I made my way back , but it just didn't occur to me that the car would ever need oil so soon given that I put some in a few weeks ago! I'm amazed at how much oil this car consumes!!! I changed my oil on my NSX and Ferrari every three months, and that too because I wanted not, not because it was required. Usually the oil level would have barely have moved. The C4S inhales this stuff. - Fourth, I've stockpiled two more quarts in my car. God forbid this happen again, at least I won't face the possibility of being stranded, with the nearest gas station being miles away - I'd suggest you do the same. I'm going to do some searches on this forum on 996 / C4S oil consumption, but I'm still shell-shocked on oil consumption. Help me out here - is this normal?? Best, Rasta.

You should put the car on a lift or jacks to see if you have any oil leak. Alternatively, look at the garage floor.

No leaks. The car goes on a lift and I've inspected it. Nothing. I should add that I got the car with 1,600 miles on it. It now has 3,200 miles on it. Wondering if this is happening because the car hasn't really been broken in till now?

The car has almost 10 quarts of oil. It should not go so low in 1600 miles to shut engine off. I don't know at what level the sensor shuts down the engine but I would think it would be around 5 quarts or so. You could easily be a couple of quarts low in 1600 miles with a new car but I wouldn't think that should not be enough to shut off the engine. You need to get a handle on exactly your oil usage and if you have a sensor problem or what?

I would definitely check the dipstick on the regular, and also check before you decide to fill her up with more oil, you dont want to overfill. The 996 should not consume oil at the rate as you described. Let us know what you find though.

You might have had a LOT of fuel dilution that burned off (evaporated) on the 80 mile trip.

I know oil consumption prior to break-in is popular and I'd suspect that's the cause. keep an eye on it especially after breakin.

It's common. but not normal, mine does the same thing.

Thanks for all your thoughts. I think the fact that the car is technically still being broken in (was a garage queen for two years) does have a part to play. Will continue to keep an eye on the usage. Whew! I'm missing the connection here to oil usage.

You're not alone Rasta. I always have 2 quarts in my garage. I get some soot after a long drive all around my rear bumper. I'm thinking it's the oil intentionaly designed by the P engineers to well lubricate the piston rings in sprited driving which the car is designed for.

When the engine is cold or you drive slowly fuel tends to blow by the rings and get in the oil. 8% fuel in the oil is not unusual. When you go on a long trip and the engine gets hot the fuel boils off and the oil level drops rapidly. I think it's discussed in the owners manual.

In my '02 C4S I use almost no oil used very little durring break in as well. However, on the track if the revs go much over 6000 and I am off and on the gas then I get some blue smoke upon restart. Even under track use I never get the kind of oil consumption you're talking about and in the absence of leaks you've got to wonder where all that oil is going. If you top up again and then burn a quart in under 200 miles it's time for some further diagnoses. Just my2c fwiw.

My 2003 C2 uses about 1qt every 1000 miles. I was just compaining to my dealers service department about it when I had it in for service and they indicated some cars need 1qt every 650 miles and this is normal behavior. It seems some people have issues and others don't. I have also been told that your guage me drop if you do some spirted driving. Something about water evaporating.

Interesting. Thanks for the primer ebaker. Appreciate everybody weighing in. Seems others have have had similar experiences, but perhaps not to the extent that I have. Now that I've topped it off, will definitely keep an eye on usage. Will report back. Best.

I'm at 300 miles and down about half a quart.

Start driving the car very hard once in awhile and you'll see the oil consumption drop, unless you have a mechanical problem.

I think that may have been part of the problem. The car was a garage queen prior to me buying it - it only had 1,600 miles on the clock in 2.5 years. I'm generally a fairly aggressive driver, and I think this could just be the car settling in after being driven hard after a long time. As an aside, I'm a little nervous right now. When I poured in the the oil yesterday and checked the diagnostic, the marker was at the top end between the two lines. Today, the oil level is actually showing higher than the top line, implying overfill. Now I want to get the oil consumption going so the level reads right. I'm hoping there are no issues with the oil being a little higher than it is supposed to be. What a weekend.

The best way to verify oil level is to let the car sit for at least an hour. I look at the gauge before starting each morning. Sometimes, if you check the level too soon, you will be compelled to add oil and overfill. Make it a practice to check the level while parked in the same place and the car has been sitting for at least an hour. You can remove some oil by removing the oil filter and emptying it out. My 99 burns NO measurable amount of oil, ever. Being that your car was not driven often, make sure you are not leaking oil from the RMS. This seal is prone to leak on cars that sit for extended time.

Is 10-40 ok to run in the engine?

I check my car using the e-check every day I drive it. When I first got it with 15k miles on it, it burned a lot more than it does now with 26k. Guess it just takes a while to break in.

How is it, with a car that has nearly 10 quarts of oil, it simply will not start because it is low only ONE quart. I think there is something bigger going on with your oil issue. I have been down a quart before. Both by trigger of the blinking light and as well the flash of the oil light. Additionally, when you are low on oil, the car will run a diagnostic each time you put gas in the car, and it tells you to check engine oil level. This happens to me a lot. It's no biggy though. My biggest concern for you is that you added one oil and the level showed normal. Each of those tick marks indicates 1/8 of a quart of oil, so when you are down at the bottom, you are merely one quart low. However, in that you got this odd message that the car would not start, that is pretty serious. I have been a quart low many, many times and never have I had that message appear. I wonder if something is not right with your computer in how it measures your oil level. Or that you really are much lower than one quart. I don't want to alarm you, but I would give your dealer a call and ask him about that warning and see what they say.

10w40 should be fine if it's ACEA A3 rated and if the temp stays above about 5�F. 5w40 is OK down to -12�F.

Personally, I would have the oil changed at the dealer to make sure the level is set right. You also didn't mention whether you got your hands on another quart on Mobil1 or whether you had to mix oil brands. I would get an oil consumption record going, and also double-check the oil level manually using the dipstick rather than rely solely on the OBC, which may be malfunctioning. I have an '03 C4S with 11K miles. I've driven it pretty hard and have put about 1K miles on it. The OBC shows no reduction in oil level at all since I got it. Rgds, Ryan

I think you guys are right, I am going to run the issue past my dealer and potentially have them check the car out for a malfunctioning OBC. Will check the dipstick manually this evening and let you guys know the findings. I believe both earlier and recently, I used 10W-40 grade oil so there should be no mixing of oil grades. Would it be an issue if there was? Or if a synthetic grade was mixed with a natural one?

I would stick with the 10W-40 or, if you are doing alot of driving inland where it is hot, 15W-50, which was one of the original oils speced for your car. In the summer, your engine temps regularly are reaching 215 - 220F just driving around normally.

I have a '99 996. Is there a diagnostic check on this model year that automaticaly reads out the proper oil level? I notice sometimes I see an oil indicator light when I start the ignition, but its only on momentarily and I am not even clear what it means. Thanks.

The '99's did not have an electronic check. The oil light you have at startup is a warning light that will come on if there is an issue. Later year cars (I believe it started with the MY02's), have an on board diagnostic that lets you monitor the specific level of the oil. In my case, the feeling may be that this is malfunctioning. Either that, or there may be something is wrong with the car, as it is seems to have consumed a signficant amount of oil within the last six weeks.

The 99's DO HAVE an electronic gauge just like all the later models. This gauge has proven to be as accurate as the dipstick.

Thanks for the info...so hopefully I will never see the oil light on for an extended period of time. Good luck with your car.

My apologies for the confusion. Was this the case for all 996's 1999Porsche911? I had an '99 a few years ago, and I don't recall it. Maybe I was just too enamored with the car to notice -

As far as I know, they all have had them.

Don't worry about mixing a couple of quarts of 10w40 with your regular oil. If it was a cheap non synthetic oil you might change the oil 1000 miles earlier than usual. Modern major brand oils mix without problems.

In theory, synthetic and dino oil are compatible. However, since the car is driven hard, I would stay with the Porsche recommended Mobil1 synthetic. Do you know if Jack Daniels did an oil service before they sold you the vehicle?

I am using 10W-40 regular, not synthetic. Jack Daniels indicated that the oil had been changed.

Am nervous about the fact that oil is now showing "overfilled" (over the top line) through the OBC. Will check in with the dealer today and will also check the oil through the dipstick, but as 1999Porsche911 notes, may have to remove some later tonight if it seems high. Very mechanically obtuse, but I assume that removing the oil filter and emptying it out is not that difficult if you follow the manual.

[QUOTE=Rasta]Am nervous about the fact that oil is now showing "overfilled" (over the top line) through the OBC....QUOTE] The OBC & Stick level when the engine is in it's normal operating temp will differ by 1 to 2 bars than when it's cold.

If JD changed the oil, they are likely to have used Mobil 1. Personally, having a qt of dino mixed with synthetic would bug the hell out of me. If you are not mechanically inclined, I suggest you do not try to resolve the problem yourself by removing the oil filter and reinstalling. Take it to the dealer for an oil change. Report what happened and let them do a diagnostic on the car.

I'm starting to take the engine to 4k a little more often. I'm not worried about the consumption yet. I believe the Turbo motor is set up looser than a non-turbo motor so consumption will be higher IMO.

I spoke with the dealership today. Salesman had never heard of the engine cutting off and the error message displayed, although acknowledged heavy oil consumption could have come from the fact that the car is finally being used aggressively, as opposed to just being babied. He indicated I should monitor the consumption and report back if anything strange like this happens again. Also got a call into their service department to reconfirm. Haven't had a chance to check the dipstick manually since I came back late from work. Will try again tomorrow.

Vic, def take it into the dealer, they need to note your service record that you are c/o a oil leak for the future, if need be. Have them change the oil as well, don't f with the oil filter, easier to drain the pan, but you'll need a new gasket for the plug, just let the dealer deal with it, they need to fix it for you, btw salesmen don't know **** about these cars. later chris

My car was consuming 2 quarts every 200 or 300 miles or so. After a long drawn out proceedure PCNA replaced the engine. So far 0 oil consumed in about 1500 miles.

I'll follow up with the service department tomorrow and see what they say Chris. Best, Vik.

Spoke with the Service Shop. Were surprinsingly nonchalent about it. Indicated the automatic shutoff was not atypical. Chalked it up to a combination of using regular oil ("best to use synthetic Mobil 0-W40"), aggressive driving, and the fact that the car has low miles and is therefore still settling in.

So as usual, Porsche Technicians have no idea what they are talking about? Incompetence is far to common. Godd thing you didn't tell them what kind of window cleaner you use on the car or they would have concluded you were using the wrong kind.