Kevin

Manny, can you ask your wrench "how he did your oil change"

Did he drop the oil out of the turbochargers? Basically I would like to know how many drain plugs did he remove?

Kevinmacd

Just a question to help me understand the oil level indicator more. I understand all being discussed, but what happens if the fill in the tank is shown as to the top of the indicator? Otherwords does it show any crazy symptoms? I know there can't be any foaming since these cars are true dry sumps!

Dock

Larry...Any opinion on this at all?

manny_g

let me try to answere/clarify some of your questions. a total of four to five quarts of oil was drained entirely from the engine. most of the oil drained came from the tank. with respect to the turbo chargers one drain plug was removed from each of the "reservoir". a total of four plugs were removed. one from the case, one from the tank and two from the turbo chargers. over seven quarts of oil was added. after adding the first five quarts the oil display indicator displayed just over half way between the low and high marks. after adding the first five quarts, i did notice that it did not require much more to completely top off according to the indicator.

LVDell

So after draining what probably accounts to somewhere between 8-9 quarts of oil you started it after only adding 5 quarts???

Macster

A fill to the max line is what the factory manual oil change section advises. I've run my 03 Turbo at the max fill line and haven't seen any crazy symptoms, any behavior out of the ordinary at all.

There is always foaming in the oil. A dry sump system in fact tends to aerate the oil more than a conventional system because of the action of scavage pumps.

Any oiling system worth the name though has swirl/defoaming pots that aerated oil is fed into. These pots separate most of the oil from the air. This oil is then routed to (eventually) the oil sump or the oil tank.

In the case of Turbo I would not be surprised that some of this oil still had some bit of air in it. But the location of connection of the line that returns oil to the oil tank, the location of oil pump pickup, in-tank baffling, and a good amount of oil in the tank (roughly I estimate no more than 2 quarts less than the tank's oil volume at hot idle when the oil level is checked) ensure the oil pump never ingests any of this oil. The only oil it ingests has shed whatever air it had left in it from the swirl/defoaming pots.

Sincerely,

Macster.

Macster

Sorry, I know you asked Larry, but I can't help but respond. The answer has to be no.

Remember we only can check the oil level when the engine is running and the oil hot.

At high rpms a considerable amount of oil is in suspension in the engine. Under the best of circumstances for an engine the size of the Turbo's I'd guess maybe 2 quarts of oil. Maybe. More on this below.

While underway if we could check the oil in the oil tank I think we'd see its level way below the the hot idle check level and maybe down to the min line or even lower.

Now it could that the oil level in the tank stays rather constant cause of course the scavage pumps are overdriven. The idea is to draw in any air/oil and get this fed to the de-foaming/swirl pots and perhaps the oil cooler and then back in the oil tank pronto.

Still, I bet that under some operating conditions the oil level in the tank drops some. This is why the oil level check system requires the engine run at idle a while (20 seconds is the most time I've seen the oil level check require before an oil level check can be done, while if the engine has been idling a while just 5 seconds is required). To give the scavage pumps time to ensure all the oil that can be scavaged is scavaged and the oil level in the tank reflects the true oil level. Without any variation or inconsistency. Any change in oil level must be due to a real drop in the oil level (or due to the adding of some oil) and not because the oil level checking system and the engine's oil system reads different sometimes vs. other times.

Sincerely,

Macster.

Kevinmacd

Thanks Macster. So just to clarify you fill to the top bar, the one beyond the arrowed level?

Macster

No. The oil level should not above the max line level. The highest the oil level should be to the max line. No higher.

The manual states to add 7.8l of oil (if the filter was changed) and run the engine until an oil level check can be performed then to add oil until the 7 lowest lines/segments are lit. Roughly each bar represents 1/4th of a quart of oil, so if the oil level is 2 bars below the max line add 1/2 a quart of oil. Or as I prefer to do add less than the estimated amount and sneak up on the oil level.

I've watched the techs change the oil in various cars and they don't just pour oil into the engine indiscriminately. They add the correct volume of oil, in the case of a 996 Turbo 7.8l of oil, then after getting an oil level reading adding oil in small increments (roughly I would guess in 1/4 quart amounts) until the level is correct. They may add oil once, or sometimes more than once to get the oil level to the proper level.

You want to make sure the car's on the level, as level as you can get it. If the car's too far out of level the oil level check won't work. A warning appears informing you the car's not level. (There's a warning if the engine is not at idle speed, the oil is not hot enough, or if the car is moving.)

But even if the car's level enough, but still not dead level, while the oil level check will work the level displayed can be different. I have seen at least 1 and possibly 2 bars of difference depending upon the car's degree of levelness and in which way the car's not level. It doesn't take much out of level to affect the oil level reading.

Sincerely,

Macster.

Dock

I have no problem at all with you posting your opinion on this matter.

If you mean that you do not think that being 1-2 bars (0.26-0.52 qt) below maximum on the oil quantity indicator will affect the oil quantity and/or oil pressure at the intermediate shaft, then I agree with you.