docboy

Just had my 1st oil change/inspection at a recommended P-car indy shop on my 2002 996tt. Been about 1yr and 2-3k miles since last service. Aside from slight leakage of front CV joints, everything else good.

I had to hurry after the oil change was finished due to errands, but when I finally got back home I noticed while at idle:

1) The oil pressure was fluctuating between 2-3 bar
2) The oil level on the computer screen is 2 bars short of max

Prior the oil change, the oil pressure gauge was pretty much near 5, and the oil level was at the max bar.

Is this normal? Should I give it a few days for the oil to "settle" down? Or was not the full amount of oil added?

s65e90

The oil level gauge is a window. It doesn't have to be at max just within max/min. Oil pressure at idle is not the top of the gauge, it moves. It sounds like the issue is psychosomatic as you just had the oil changed and then were thinking of it.

Dock

The two bars below max seems to indicate that they didn't put as much oil in as they could have; however, it's good that they didn't over fill it too.

My idle and warmed up oil pressure is steady at less than 2.

gophaster

My wamed up idle is right around 2 as well.

docboy, are you sure you're not comparing full warmed up pressure to cold or even just cool pressure readings?

docboy

Very possible that I'm just pyscho and **** about this... I'll give my mind a few days to settle down

Good point. I'll wait a few days and see the cool pressure reading, and let everything including my mind to settle down. Cool pressure I'm confident it's 5 bar pressure.

"02996ttx50

also you're maybe 2/5 of a qt low which isn't mission critical but they probably only added 8 qts. i'd drive around a bit and add a 1/2 qt.

i like to keep it topped up even knowing a 1/2 qt down doesn't matter.

jeanmarcboilard

You might have had thicker oil in there before and they filled it up with 0W40. That would cause lower oil pressure.

Macster

The oil pressure gage needle of my 2003 Turbo bounces a bit at idle. It can jump up to 3 bar then just as quickly drop back to 2 bar or thereabouts where it is when the engine is fully warmed up. At other times the needle is quite stable.

As for the level being down a couple of bars: The indy shop apparently didn't add enough oil. This calls into question of how much oil was actually put into the engine.

As I have mentioned before it is at oil change time the oil is properly drained (hot and for a certain amount of time) then a *known* quantity of oil is added (7.8l is the amount given in the Turbo factory manual but my tech sources tell me that the actual amount is tied to the car's VIN) then the oil level checked afterwards to *confirm* the electronic oil level reading is correct at the max. line but not above it and not below it.

By following the proper procedure not only does the oil get changed but the proper functioning of the electronic oil level measurement system is confirmed so you then have some high degree of confidence when you use it to obtain an oil level reading it is reporting the actual level.

My advice is to top up the oil level. I prefer to run the oil level of my Porsche cars at the max line. For the Turbo and the Boxster the max line level is when the oil is hot. I prefer to start out with the level at the max line after an oil/filter service so I can get a good idea of how much oil the engine is using. Since I have the oil changed every 5K miles it is easy for me to when it comes time to add oil and I add a quart that I know the engine has used a quart of oil in say 4K miles.

T10Chris

Peter, everything sounds normal to me from your description. Add oil if you like, or not. It isn't going to make a difference with how you use the car. The amount measured is the amount of oil in the reservoir, not in the crankcase like typical car. It's like having your windshield washer fluid be in between full and low. More oil gives more heat transfer capacity so if you were to drive hard it would be good to have more, but really makes no difference for street use IMO.

There's no way anything regarding fluid capacity ties to the VIN of a car, pure nonsense from him/he is blowing hot air.

I have the factory service manual that the techs work from. The actual oil capacity of the 996 Turbo is over 12 liters, but there is no way to get it all out in standard oil change per Porsche, typically 3-4 liters remain after all drains are opened.

Also no way to consistently remove the same amount in each change. The idea is to add the same amount that was drained, but approximate values are given regarding what "should" come out and no tech measures how much they drain to add back the exact amount, they don't have time for that..

The amounts recommended to add before checking the oil after oil change per Porsche repair manuals are slightly higher than you mention... It is 8.5L (8.98 qt) without filter, or 8.75L (9.24 qt) with filter.

"02996ttx50

on a simple drain ( not incl the turbo's ) the time honored method involves adding 8 and once up to op temp then adding the extra 1/2 to 3/4 qt to bring it to the top line of the guage.

porsche also recommends gear oil changes at 90k so forgive me if i don't equate all their factory recommendations with the gospel lol

Macster

You do not want to add back in the same amount that was drained. The amount could be wrong, too little or too much.

These sources have not misled me with regards to other things they've told me. The quantity of oil can change if a mid-production change was made to something that affects the amount of oil the engine/tank holds. The odds are the quantity of oil remains the same but it doesn't have to.

My printed reference says the amount of oil is "approx. 12.5l".

Can't remove the same amount of oil every time. This varies depending upon how much oil is in the engine. The idea is to leave the same amount of oil in the engine every time, then add back in the correct amount of oil to bring the total amount of oil in the engine to the correct volume and to confirm the electronic oil measurement system reports the correct level.

This is accomplished as I mentioned above by bringing the engine up to temperature then allowing the oil to drain 20 minutes.

Your numbers regarding the amount of oil to add differ from the numbers in my source, which is a Porsche Turbo factory manual. In my source the amount to add is 7.8l. So there is a disagreement even between the printed sources.

While the engine is (probably) ok with the oil level (measured hot) less than max running the oil level closer to max provides a bit of a safety margin.

A hard working engine has a considerable amount of oil in suspension in the crankcase in the heads/under the camshaft covers. This oil lowers the level in the oil tank.

Additionally the oil routed to the tank still has some air in it. Baffling helps to keep the more aerated oil from being ingested by the oil pump but with a low level of oil to begin with the risk is the oil that is ingested by the pump has more air in it than it would have were the oil level be closer to maximum.

Kevinmacd

I use 5w-50 and my oil at idle after warmup sits about 2.5 bars. Oil change with turbos drained crankcase dumped and oil tank is little over 9qts with filter

RngTrtl

kind of OT, but why would you use 5w-50 in FL?

Carlo_Carrera

Better resistance to the high year round temperatures.

"02996ttx50

^ seems to work for me also. particularly in high outdoor ambient temp.