[WillySwan]

I have the 3.0 litre diesel. Oil consumption isn't the problem, it's the dipstick reading that's the problem.

I AGREE! Reading the oil level in my 2015 WK2 EcoDiesel is the more difficult than any other vehicle I have owned over the last 45 years.

The only time I can get a consistent reading is at room temperature after the Jeep has sat on a level surface overnight. After that first dipstick reading, it is impossible for me to get a clean dipstick reading. I have read people suggesting to VERY SLOWLY insert and remove the dipstick to get a reading. I have had zero luck when trying that.

Like you, my dipstick reads low when I measure after sitting overnight. It measures right at the "MIN" level (see below). I have no oil consumption issues and the reading remains consistent between oil changes. I am certain it has the specified 8-quarts (7.7 liters) since I change the oil myself.

My dipstick has "100F" stamped on the same side at the MIN and MAX levels. I have assumed that is the temperature for those levels. 100F is about the temp of my garage here in Texas. Like you, I have considered adding an additional quart/liter of oil.

 

[WillySwan]

I would never add a quart just to satisfy the dipstick. If you change the oil yourself and you use the recommended amount (7.7 or 8 quarts in your case) wherever the oil level is on the dipstick, then that is your full line...

I understand what you are saying. Here is my current thinking on this - what do you trust - a written specification or a physical measurement? Obviously, 8-quarts is satisfactory as that is what the factory recommends and warrants. But, what if you could put in another quart?

What is the downside? If the oil is too deep in the pan, the crankshaft will catch the oil as it rotates and whip it into a frothy frenzy. That's probably not real good for the oil. In addition to impacting efficiency (mileage) from the additional drag, there is maybe the possibility of sucking air in the sump pickup and loosing oil pressure in an extreme case. All of these are reasons why racers use windage trays (my understanding). Typically engines are designed with some headroom between full on the dipstick and contact with the crankshaft.

What is the upside? My opinion - the upside of another quart of oil would be that, with an additional 12% oil capacity, the oil would be doing that much less "work" - the oil would be cycling from the pan through the engine fewer times. There might even be a small impact on oil temperature, but I'm not convinced on that.

As a point of reference, the oil capacity for the Mercedes V6 3.0L turbo diesel used in the Sprinter is 13 quarts. The Sprinter 4-cylinder 2.1L diesel takes 12 quarts, Obviously a different engines, but most diesel engines are designed with high capacity oil sumps for a reason.

I'm becoming less of a rule follower as I get older. If the engineers at VM Motori were capable of designing a dip stick that accurately represents the oil level in the engine, then I see no downside to adding a additional quart to bring oil level up to the full line. Just my opinion.