Engine overfill?

[staticx57]

Due to my slightly paranoid nature of my car now I may have screwed something up. I have an 02 C2 Tip. Long story short I have a freshly rebuilt engine with new everything. I have a history with the car after the rebuild due to smoking out the back. The initial problem quoted was a vacuum imbalance which they fixed. This solved it for a while. After a while it did it again and they ended up replacing the AOS which is where i am now with new everything. After driving my car around for a few days I checked my oil level with the digital gauge, the engine was hot and checked a few minutes after I turned it off. The gauge showed less than minimum. To me this was a problem. I added about 3/4 of a quart of oil to what ever amount was in there. I am assuming the shop had it right and I screwed it up so I am not sure on the exact amount. Anyways I now get smoke out the back. at first it wasnt a problem. After a few miles of highway driving going to pass someone at 4k+ RPM I noticed smoke out the back again. This is a problem. Easing up on the RPMs would clear the smoke. In fact I drove it maybe 10ish miles to my house with 0 smoke as long as the RPMs were low and I tried full throttle right before I got to my house with 6k ish without issue. Now my car smokes on start up. At first it was enough that it looked like I was at a smokeout. I tried starting it up a few more times no more than 20 seconds. Each time I get less smoke but still some. The car has no issues running at idle for the times i Have it running. However the car has been sitting as I don't know what to do with it and if it is something I can do myself. I am not very mechanically inclined.

[Porca911]

IMO it sounds like you may simply of over filled the car with oil. Always a good idea to let the car sit for longer than 5 minutes on a level ground to let all of the oil settle before you check the oil level. I would check the cars oil level using the dip stick under the hood. With any luck it is simply a case that you have over filled the car with oil. In which case as you say you are not very mechanically inclined simply go to a reputable garage and get them to change your engine oil (and oil filter) with a good quality fully synthetic 5w/40 seems to be the oil grade of choice on older cars like ours :) Good luck and let us know fi that sorts the issue out for you.

[logray]

...the engine was hot and checked a few minutes after I turned it off. The gauge showed less than minimum. To me this was a problem. I added about 3/4 of a quart of oil to what ever amount was in there...

If my car is hot, I wait a MINIMUM of 30 minutes for the oil to drain into the sump before checking the level. If you only allow a minute or two of draining time the dash gauge and dipstick will show much lower than normal oil level, and that doesn't mean you are supposed to add oil.

...However the car has been sitting as I don't know what to do with it and if it is something I can do myself. I am not very mechanically inclined.

If you are not able to check the level, drain the oil, and refill to the proper amount as per the factory specifications I suggest you have the car towed to an independent or dealer to have the oil changed and properly filled.

Then drive the car, it may take some time and "good hot higher rpm driving" to "burn off" the residual oil and the smoke to decrease. This is similar to how you burn off the residual when there is a failed AOS.

Edited March 14, 2012 by logray

[staticx57]

I really appreciate the responses. Checking the oil is only a matter of finding a level surface which my driveway is not. I can't imagine driving it a very short distance would damage it, something like around the block or even jus shuffling cars and finding room in the garage? I was reading some of the other threads and they used a device to pump it out of the fill tube? Is that an option with these cars?

[JFP in PA]

I was reading some of the other threads and they used a device to pump it out of the fill tube? Is that an option with these cars?

Not really, there is too much stuff (baffles and air separators) in the way; there was a recent post where an owner tried to do this, could not get the hose down to the oil level, but did manage to get the hose stuck in the engine, requiring a flat bed to the shop where the sump cover was removed to get the hose out.

If the engine is slightly overfilled, change the oil filter which will remove a bit less than a quart from the system. If it is way over filled, just drain it and start over again. In any case, do not run the car with excessive oil in it, it can get sucked backwards thru the AOS and smoke like Hell, or even lead to a hydro lock and a dead engine. Fix it..............

[staticx57]

Well I rolled the car to the end of the my driveway which is about as level as it will be without starting it. It is a very slight incline with the nose pointed up. I am aware that this is not ideal but it is the best i can do without starting it. According to the dipstick which I am having a heck of a time reading the car is at the max level without going over. The confusing part is that little I am guessing plug at the top just above the meter, that seems to get covered in oil but the actual meter itself the oil level rises to just before the max indicator. The onboard computer shows the level oil level as at the max level but not over. None of the indicators are blinking as such when it is low. This is with the car sitting with cold ~70 F degree oil.

I am guessing between what was already burnt and the little I did add it is ever so slightly over filled?

[logray]

Yes, your description sounds right, however pictures are worth a thousand words if you can post some.

Hot oil expands though.

If it were me I would drain about 1/2 to 3/4 of a quart, either by pulling the oil filter a couple times (pull, drain, install, run, pull, drain, install, run).

Or just drain al the oil and fill back in the correct amount.

[staticx57]

I took all the relevant pictures that I thought of. Kind of hard to make out the dipstick. I put an arrow where the oil looks like it stops.

[logray]

and this is with hot oil? cold oil? how long of a drain time? what viscosity and brand of oil?

[staticx57]

Cold oil. the car has been off for a few days now. 5W-40 I believe the shop used-Torco.

[logray]

If the dipstick is right then it looks to me like you are running basically "full to the brim". When the oil heats up it will probably go closer to the totally full mark on the dipstick (and beyond the level on the dash). Sometimes the dash indicator is not as accurate as the dipstick.

Speaking of dipstick, since you have a 2002, you should read TSB 1/02 1716, some model year 2002 cars require a new longer dipstick to read the proper oil level.

If I were you I would still drain maybe 1-2 oil filters worth of oil to put the oil more in the safe zone (and especially adhere to the above TSB since your dipstick might not be accurate).

When my oil is totally cold, I like to run it half way up the dipstick, which usually works out closer to 3/4's full once it's hot. Of course the type of oil and drain time is going to affect this.

[jay abrams]

Stupid question......

Why can he just loosen the drain plug and let some oil out? Will it reseal poorly?

Jay

[JFP in PA]

If you are going to use the drain plug, you may as well just pull it and drain the system; you should replace the crush washer every time the plug is loosened, which is why dumping the filter was suggested as an alternative..............

[staticx57]

Thanks guys, unless this is stupid simple I am going to have to let one of my more mechanically adept friends do this.

[logray]

Yep if this sounds foreign to you have someone else do it.

[carrera3.2]

Not to start a raging debate on the subject of removing excess oil from a 996 engine, but I have removed small amounts (0.25-0.5 qts) of oil via the dipstick tube from my '03 C2 several times with no problems using an appropriately small diameter piece of "Tygon" tubing and a hand-operated "mini" vacuum pump of the type some use to flush brake systems. Before putting the tubing down the oil dipstick tube, I measured the Tygon tubing against the Porsche oil dipstick and made a mark on it so that I did not get into the internals any deeper than the distance traveled normally by the dipstick. This was to avoid any snagging on the baffles, etc., as pointed out by JFP in PA above. That would be a bad thing to do, for sure. Cautiously following this procedure, I have not had any problems of oil removal.

[jay abrams]

If you are going to use the drain plug, you may as well just pull it and drain the system; you should replace the crush washer every time the plug is loosened, which is why dumping the filter was suggested as an alternative..............

That's was what I was wondering. Thanks JFP

Jay

[staticx57]

Well I(not I exactly) removed some of the oil, one canisters worth. It no longer burns oil on start up and during operation. I even took it for a 40~ mile drive and everything seems normal. Fast forward to today I go to drive the thing and I notice that now it will peg the oil pressure way high. On start up and near idle (no more than 1.5k RPM) it will stay at 5. At 3kish RPMs with the engine warm it will hit the 5 mark and idle will be 3-3.5. Is this normal? I do not want to take the car near the high RPMs with the car doing this.

Edited March 22, 2012 by staticx57

[logray]

Your oil pressure could be perfectly normal depending on temperature, and even at "normal temp", 3 bar is only .5 to 1.5 bar higher than normal, which is not necessarily a bad thing. What temperature did you observe this at? Specifically, since the dash gauge is inaccurate, can you post a pic of your instrument cluster when you are seeing 3 bar at idle?

Generally speaking, high oil pressure is not a concern compared with low pressure. To a point of course, but the stock gauge doesn't depict anything above 5 bar.

Also did you look at that technical service bulletin I posted for your model year car? That is VERY important to reading the correct level of your oil, if your engine happens to fall in the range of cars that require a new dipstick.

[staticx57]

I understand that it isnt fully warmed up when I took this picture but this still seems way to high for just idle.Any revs will quickly send it to 5.

As for the TSB, I am not exactly sure where to find it.

Edited March 22, 2012 by staticx57

[logray]

As a contributing member here, you can find the TSB under the DIY Tools menu at the top of the website. You might also be able to get it from your Porsche dealer.

Regarding the oil pressure. What you show there looks normal, even though your car isn't warmed up yet. Once the car is warmed up, generally anything around 1 bar to 2.5 bar at idle is normal (depending on the oil temperature, viscosity, etc.).

It seems like you are equating oil level with pressure. While they are somewhat related in certain situations, you will not be able to notice a difference in oil pressure if your car is substantially overfilled. Additionally, the engine is fitted with a pressure relief valve, which under normal operating of the engine by design once the oil pressure reaches the designed "max" (which is still below what would be considered safe), the relief system will hold the pressure where it needs to be and the rest of the "pressure" is returned to the sump. Oil pressure is also a function of engine speed, since the pump is driven indirectly by the crankshaft.

So in other words a quart off in either direction from "middle filled" is not going to show up on your pressure gauge. And anything in the overfilled direction is not going to show up on the pressure gauge.

Again, generally speaking higher oil pressure is GOOD (what you want to see), it is safe to operate the car at any RPM when the oil pressure is at 5 bar. Avoid excessive RPM until the coolant temperature gets to around the mark below the 180, try to keep it below 4000 rpm. All of this is spelled out in the owners manual.. If you haven't read it I highly recommend reading it.

Low oil pressure is bad. The manual states 3 bar at 5000rpm warm engine is normal IIRC. Anything above that is gravy (good/healthy). Below that, not good.

If you see the oil pressure dip quickly or randomly with a steady RPM, there is an oil pressure problem which could be a number of things. Substantially low oil level will show up as low oil pressure (quick drop of the needle) when you make a hard turn. Racers who take the car to near the limits require special systems to help keep the oil pressure up and the oil temp down, as there are some "shortcomings" of this engine design under those extreme conditions. Daily drivers who don't push the car to the limit on a race track will not expericence these issues. There can be other internal problems which create a low oil pressure problem, but have nothing to do with the level of oil in your car.

Lastly, the accuracy of the 996 gauge cluster is less than to be desired, but is "close enough" for most people, for example the temp gauge numbers are pretty meaningless, the oil pressure gauge has been noted to be very slightly off, battery slightly off, speedo slightly off, etc..

Edited March 22, 2012 by logray

[fbgh2o]

I understand that it isnt fully warmed up when I took this picture but this still seems way to high for just idle.Any revs will quickly send it to 5.

Mine looks like that before it is up to temperature. Cold oil will idle around 4.5 to 5 bar and until the engine is fully warm it wil read anywhere from 2 to 4 bar. Note that it takes a while for the oil to heat up. You car may show 180F on the coolant but the oil will not be fully hot at that point.

[staticx57]

I understand that it isnt fully warmed up when I took this picture but this still seems way to high for just idle.Any revs will quickly send it to 5.

Mine looks like that before it is up to temperature. Cold oil will idle around 4.5 to 5 bar and until the engine is fully warm it wil read anywhere from 2 to 4 bar. Note that it takes a while for the oil to heat up. You car may show 180F on the coolant but the oil will not be fully hot at that point.

Thanks for the answer, this was what I was worried about. Perhaps it's been too long since I really drove the 911 that I was use to seeing oil pressure not that high.

[BostonC4Scab]

This high pressure gauge indication happens with my car as well. I had the car checked out and was assured not to worry about the gauge...as long as the indicator light does not come on. All has been good for 2 years now.

[Jetskied]

Oil does not warm up as fast as the coolant. IMO the oil is still cold and thick enough to give you the pressure you are having. I would worry more about low pressure.