For engine gurus: Why overfilling oil is bad for engine?

[Delboy]

Originally Posted by M-A8

...sooooo, I've noticed no difference after leaving dipstick out for 35min, still about 2mm above the MAX line.
Would you classify this as a possibly dangerous overfill???
I can't see 2mm being dangerous personally purely because a 2mm mistake is so easy to do and having gaskets blown each time you overfill by 2mm would be mad

Wah wah wah, Warning failure imminent, failure imminent Wah wah wah

Only kidding I'm sure 2mm will make no difference Marcin

[Goran]

I find the Audi dipstick annoying too, wiping and dipping can result in weird high readings, sometimes wiping and dipping 2 or 3 times produces a better reading but results in smearing more oil up the tube. Testing when hot can give a lower reading if it hasn't drained enough.
The most annoying thing is trying to see the oil level with fresh oil just after an oil change, its too clean and transparent.

In the past I have resorted to wrapping some old 1mm or 0.7mm solder wire around the metal strip between the plastic stops, the horizontal bars of wrapped wire make the oil level much easier to see. The solder wire is removed immediately after test, you definitely dont want to leave it in there.
I think Audi should have designed the metal strip with deep horizontal groves.

[Adrian E]

If you think the '8 one is bad, you should try the one they supply with the C5 A6, which is all plastic! It's damn near impossible to tell where the level is at any time

I find leaving the dipstick out for a while and checking it once gives a fairly decent reading on the '8 - as soon as you've pulled the dipstick up the tube it's left a residue that'll influence another reading

[jza8]

I always try to fill to middle of the level, no point having it close to max.

[Goran]

Originally Posted by jza8

, no point having it close to max.

Ah but there is! what if you want to do a 1250 mile hour journey in one day
Although in my case the level didn't drop much as my car doesn't eat oil.

[jza8]

Most of us are not doing that kind of mileage in a day often, and I always carry a litre in the car.

[tonupkid]

First prize for the worst Audi dipstick has to go to the Q5. There isn't one. Nope, no dipstick at all, just a readout on the MMI. So you can trust that can't you

Our Q5 is using 1 litre every 400 odd miles and Stafford Audi are investigating, as follows.

Oil Consumption.
We have carried out a software update on the ECU and replaced the crank seal and oil separator. This is part 1 of a possible 2 part situation, please monitor and if the light comes back on within 600 miles please contact the centre. DO NOT TOP OIL UP as this can compromise the readings and delay a fix.

In all honesty Stafford have been fantastic. But if part 1 doesn't work, what the hell can part 2 be???