1800 miles on my GTS and still showing full bars but just changed oil. I'll be monitoring consumption though.

 

My service advisor told me exactly the same thing. After stories about DFI V8 oil consumption I'd read in the Cayenne forum, I asked if my guage could be checked to insure it was reading accurately since my engine had shown zero oil useage since new. They were able to accurately check the level using the external tester; my oil level was down only 2mm so the gauge was giving a correct reading.

We got to talking about the issue and my SA told of a woman whose Cayenne TT was using excessive oil for 10K miles. The service manager asked for her permission to keep the car for a week. During that time he drove as you described and finally broke the engine in; it no longer uses oil.

I attribute both my Carrera's and Cayenne's lack of oil useage to a break in strategy that was fairly aggressive with the throttle while still staying (most of the time) within Porsche's recommended rpm range. Or dumb luck.

 

I have had two 997's. The first (a 2006 997.1 4S) used so much oil (particularly in the first 15,000 miles) that I sometimes joked it used more oil than fuel. I ordered a 2009 4S (a 997.2) and bought 4 litres of Mobil 1 because "I knew I would need it". Two years and 18,000 miles later, I haven't touched a drop. The engines vary.

Don't worry about it. Go out and drive. Enjoy the car, they are fantastic.

Mark.

 

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That's ^ impossible because earlier in this thread someone said that it was FACT that DFI engines burn more oil than non-DFI engines.

 

Diesels use oil. This is masked by the fact the engine suffers more blowby and accumulates water and unburned diesel fuel. Diesel fuel being less volatile than gasoline is not boiled away like gasoline in a gasoline engine's oil.

Additionally, the diesel engine's oil runs a mite cooler than the oil in a gasoline engine which means water in the diesel oil is not as readily boiled away as well.

Thus the oil consumed by the engine is replenished by the accumulation of water and diesel fuel.

Diesel oil is specifically blended to deal with this and diesel fuel is a pretty good lubricant (more on this below) though of course I would not advise using diesel fuel in place of a good diesel engine oil in the engine.

(The high pressure diesel fuel pump, which generates extremely high fuel pressures and time after time (for every combustion stroke) is lubed by diesel fuel though it is highly filtered diesel fuel and the filter has a very good water trap all which work to prevent dirty or water contaminated diesel fuel being fed to the pump which would ruin the pump.)

Sincerely,

Macster.

 

The old break in debate.

My non-DFI 997.1 used a little oil in the first 2,000 miles, slightly less in the next 3,000 and then none thereafter. I was uber-**** about following the break in period as described in the manual (despite what many, including my dealer, were telling me to drive it like I stole it as soon as the oil was warm).

It seems in the 20+ pages of oil consumption thread in the Cayenne section that those that follow the manual for break in are using less oil than those that don't (and it's entirely possible that I'm interpreting that limited data wrong) just as it seems that those with 958 turbos are burning oil much more often than those with naturally aspirated cars.

Finally... and maybe not germane... our supercharged and direct injected V6 in our 2010 Audi A6 Avant (same motor as in the new Cayenne hybrid) produces the nasty black soot in the exhaust tips but does not burn oil. We followed Audi's break in period on this car as well.

 

I think you are overstating the oil and Diesel fuel dilution effect a bit. I drove a VW TDI in Germany for about 3.5 years. I broke it in by the book, as I do with all new cars, and drove the car regularly up to 125 mph ( not kmp). Aside from adding a bit ( 1/2 liter?) of oil within the first few thousand kilometers, the car needed no additional oil between changes over 65K miles ( again, not kilometers). The oil in that car certainly got hot enough to boil off any moisture. I also had two VW Rabbit Diesels in the 1970s ( in the US) and also did not see any high oil consumption. Now I am sure there is some ( very, very little) fuel getting into the crankcase but more likely soot than anything else. By the way, the blowby is mainly CO2, NOx, some CO and HCs, but not fuel. And, those are gasses that do not stay in the oil. Yes, and water vapor that is basically boiled off. All cars use some oil but what I keep reading about in these forums is excessive oil consumption. It has nothing to do with DI. My BMW 535 has DI and uses about one quart of oil per 16,000 miles. By the way that car is a TT and still uses relatively little oil.

So, I would think that the explanation is more likely a wide variability in Porsche's manufacturing process or the way the cylinders are finished or scored cylinders or loose pistons/rings.

 

You sure about the M3 engine being DFI? I don't think it is, but you own one and I don't.

 

Well, no I'm not. That diesel engines accumulate so much soot clearly indicates combustion is not perfect even when the engine is warmed up.

Obviously the soot manages to make it past the rings.

We already know a more volatile fuel -- gasoline -- contributes to engine oil dilution.

During cold starts and to a lesser amount at other times, liquid diesel fuel makes it past the rings and into the engine crankcase. Since diesel fuel is not nearly as volatile as gasoline diesel fuel is not boiled out of the oil but instead just continues to build up.

The condition of a diesel engine's glow plugs plays a role too into the severity of the diesel oil build up in the engine's oil since they play a big role in how well the engine combusts its air fuel mixture.

As an aside: For all the cars I've owned, all the engines I've owned, worked on, had 'tuned up' or did this myself, the biggest change (improvement) came when I had a VW dealer replace the 4 glow plugs in my 02 VW Golf TDi engine. The engine's change afterwards was remarkable. I had not realized how compromised the engine's performance had become over time.

A portion of the gases you mention end up in the oil combined with the water with which they form acids. The oil additive's package is there to mitigate the effects of this acid but it can only do so much for so long. The only way to remove these acids is to drain the oil and refill the engine with fresh oil.

I'm less inclined to blame variations in engine clearances for the oil consumption as some.

There are no reports of engines producing the usual signs of heavy oil consumption due to loose rings or worn cylinders etc that would be more common were these the causes of higher oil consumption.

I suspect that a bigger contributor to high oil consumption is a lousy AOS (air/oil separator) which simply can't remove all the oil vapor all the time from the crankcase fumes which is full of oil vapor.

The crankcase fumes with some of this oil vapor is routed to the intake manifold and into the combustion chambers where it is burned. We only see some evidence this oil is doing this when we start the engine see the cloud of oil smoke billowing out of the exhaust.

Once the engine is warmed up this oil vapor gets burned with no visible sign out the exhaust.

The only indication the owner has is the oil level dropping.

Sincerely,

Macster.

 

Sorry not to conform! I have a 5 Series BMW with a DFI engine and that doesn't use oil either. Maybe it is just me?!

 

1. Soot accumulation is NOT fuel dilution. It is soot accumulation.
2. The cold start scenerio in very minor unless you drive something like1 mile per every cold start.
3.The glow plugs are a very minor facor and operate only pre-start, during cranking and perhaps during the initial seconds. Do you actually think glow plugs are always on? A non-factor.
4. Acid may form but this has nothing to do with this subject. It simply means you need to change the oil as often as necessary.
5. Your statements point to Porsche's design as the problem ( AOS).

So the question remains. Why do many Porsches have high oil consumption rates?

 

I have an 06 997.1 and it uses a bit of oil as well. Maybe its a good thing. Maybe it indicates that the 40% extra parts over the DFI engine are getting lubricated. Who knows. Who cares? It's fun to drive.

 

A quart of oil in 650 miles "within factory specs"? Are you f'in kidding me? That kind of oil consumption in anything but a 2-stroke was always a harbinger of an upcoming ringjob. Even the Wankel in my 80s Mazda RX7, a notorious oil glutton, was spec'd at 1000-1500 miles/qt. If that's the kind of piston slop they're building into the new Porsches, I'll keep my 997.1 forever. IMS and all. Sheesh. I change oil every 5000 and in 2.5 years I haven't seen the oil measurement drop below the top bar.