Macan GTS - Oil level too high warning

[bilun777]

Did they actually measure the amount of oil they drained out?
It can't be coolant.It would be like mayonnaise in there.
Where's a good old fashioned dip stick when you need one.
I'd want them to drain it and refill with the correct amount again....

[arcamalpha]

How does the oil level indicator work on the 3.0 petrol? It's very coarse in its measurement - too much, enough, low and empty rather than a scale.

If you've not had a leak and no tell-tale then surely it's just a sodgy sensor.

Parked on a slope perhaps?

[Ray G]

Thanks for the replies, I pushed them for more info from the sample, it is showing zero contamination with a viscosity of 34 where it should be 40. That doesn't mean a lot to me.
They are still discussing it with the technical team in Germany although I get the impression they don't know what's causing it.
They suggested filling it back up and just seeing if it happens again.

Viscosity is an oil's resistance to flow and shear. It is the single most critical physical property of the oil as it affects both the wear rate and the fuel efficiency. Water is a low viscosity fluid; syrup is a high viscosity fluid. With oil, like syrup, as you increase the temperature, the viscosity lowers, meaning it flows faster, or more easily.
The viscosity will determine how easily the oil is pumped to the working components, how easily it will pass through the filter, and how quickly it will drain back to the engine. The lower the viscosity the easier all this will happen. That is why cold starts are so critical to an engine because the oil is cold, and so relatively thick.
But, the lower the viscosity, the less the load the oil can support at the bearing on the crankshaft. The higher the viscosity, the better the load it can support. Even this, however, has a trade-off, since the higher the viscosity, the more the drag at the bearing, and hence, potential power loss, or increased fuel consumption. So a compromise is chosen to minimise power loss, but maximise load support.
For domestic use, engine life is important, and in the main one should adhere to the recommended viscosity for your engine. For motorsport, engine life is not critical...winning is, so these high performance engines can use lower viscosity oils to maximise power output to the wheels, but then again they generate a lot more heat so may use a higher viscosity anyway.
The oil's viscosity is defined in the main by the size of the molecules. The larger the molecule structures, the thicker, or higher, or heavier the viscosity.
The size and structure of mineral oil molecules vary, so the average molecule size dictates the viscosity, whereas the synthetic oil manufacturing process results in consistently sized molecules of an identical structure. As mineral oil ages, the molecular size and structure changes and hence, the resulting changes in viscosity over the service life of the oil.
The viscosity of an oil changes dependent on the temperature, the pressure, and the actual shear stress on the oil as a result of flowing between moving components. The viscosity of the engine oil will depend on whether the oil is, for example, in the sump, the pump, the cooler, between the cam and followers, or in the crankshaft bearings.

Viscosity Index improvers are polymer material that expands as the oil warms up. This does NOT thicken the oil as is often stated. It merely slows down the rate at which oil thins out as the temperature rises. The base oil in use in a multi-grade (aka multi-seasonal) is the first number (such as 10W or 20W), where as the second grade is the viscosity achieved using the VI Improver (such as 40 or 50). 20W50 is a base oil of SAE 20W and the viscosity grade at running temperature is SAE 50.
Modern cars are designed to run on 10W30 or even 0W30. This is partly due to tighter clearances in the machining processes now used, but also to reduce fuel consumption even further and meet the ever-tightening Euro specifications on emissions.
Apologies for the technical summary.

[happy days]

Great article Ray G.

[boreas7]

This is odd to say the least.

There are a number of factors that may be confusing the issue, in that the oil level may not have 'grown', it may have been too high when filled and the viscosity, whilst outside spec. may have been so in the first place.

As has already been said, if the viscosity has really altered, then dilution would seem to be the cause and that must be fuel, and should have been seen in the tested oil sample, unless they didn't test for petrol. If it was coolant, then the mayo effect should be evident.

The way forward as I see it, is to drain and ideally flush the engine, fill with a measured amount and take a sample of the oil at filling for analysis. Use the car, re-check the level and re-check the viscosity after use. This should establish whether the viscosity has altered and whether the volume of oil has 'grown'.

Once this has be completed, using known parameters, then the problem may well be identified, at present however I believe there are too many unknowns and too many assumptions made.

[steve w]

Whatever the reason it needs sorting,not ideal on a £60k vehicle
SteveW

[Retired]

As above, how about a faulty sensor?

When oil drained did they measure the quantity? Won't be a precise guide because of oil left in the engine but might provide some information.

How was the viscosity checked? Result is temperature sensitive. Lower temp, lower viscosity.

If the volume of oil is rising difficult to see what else it might be apart from petrol causing it. Water contamination ought to be visually obvious.

[VanB]

Surely higher temp lower viscosity?

[Ray G]

Absolutely

[Tim92gts]

If the viscosity tested at 34 it might not have changed much, could have been 36 when it went in as brands vary a lot and the "40" is nominal for 35+ to 45-.

I did have a Ford once which seemed to be producing it's own oil. No mayonnaise but when I drained the oil the first gallon was coolant.Tim92gts2017-03-21 11:43:55