To much oil in engine?

[tight fart]

Problem
I go away in the morning
Youngest goes away Saturday morning in her Audi A1 tdi

4 pm, Dad will check car for me please before you go!

Much to much oil on the dipstick, and appears very thin.
So I'm assuming diesel in oil. (Could be 3L to much)

Quick oil change but I only have fully synthetic 5/40 not the 504 or 507 spec Audi spec.

Can you see that doing any harm, I'll change it Tuesday when back to the correct oil, & see if the level has risen, she may do 500 miles?

[E-bmw]

TBH until I had established over what period & conditions of use & confirmed the cause, I wouldn't be driving it, you could already have damage to the bottom end caused by it if it is indeed as much as you say over & it is diesel.

[paintman]

If you suspect diesel is getting into & thinning the engine oil - esp in large quantities - then it shouldn't be driven until the issue is resolved.
Or she'll be asking you how to fit a new engine.

[spyder dryver]

Could there also be potential "diesel runaway" issues?

[GreenV8S]

If it was critical to get it on the road in the short term, I'd drain and replace the oil.

It sounds as if you have diesel getting into the sump, perhaps from failed DPF regenerations, which will lead to bigger problems down the road unless you fix the underlying problem now.

[Mignon]

The word you're grasping for is "too".

[james_gt3rs]

Can someone explain how diesel could get into the oil?

[P924]

james_gt3rs said:

Can someone explain how diesel could get into the oil?

imagine an air leak, post air sensor. Fuelling will be correct before the leak, wrong after. Therefore there is too much Diesel in relation to air, whatever doesnt get burnt ends up washing down the cylinder.

[tight fart]

She didn't use the car for her trip after all and it's gone to Audi today, we'll see what they find.

[E-bmw]

james_gt3rs said:

Can someone explain how diesel could get into the oil?

Diesel injector not shutting off fully, stop the engine, diesel drains through injector, into combustion chamber & washes down past rings.

[E-bmw]

james_gt3rs said:

Can someone explain how diesel could get into the oil?

DPF regen puts in lots more diesel, once again, incomplete combustion, extra ends up in the engine as above.

[Mr2Mike]

P924 said:

imagine an air leak, post air sensor. Fuelling will be correct before the leak, wrong after. Therefore there is too much Diesel in relation to air, whatever doesnt get burnt ends up washing down the cylinder.

I don't think you understand how diesels work. The air to fuel ratio does not remain constant like a petrol engine, it varies over a very wide range.

Oil dilution is usually caused by multiple DPF regeneration attempts in designs that use a post injection regeneration strategy.(rather than e.g. Eolys). Mazda suffered particularly badly from this issue on their previous generation of diesels.

[P924]

Mr2Mike said:

P924 said:

imagine an air leak, post air sensor. Fuelling will be correct before the leak, wrong after. Therefore there is too much Diesel in relation to air, whatever doesnt get burnt ends up washing down the cylinder.

I don't think you understand how diesels work. The air to fuel ratio does not remain constant like a petrol engine, it varies over a very wide range.

Oil dilution is usually caused by multiple DPF regeneration attempts in designs that use a post injection regeneration strategy.(rather than e.g. Eolys). Mazda suffered particularly badly from this issue on their previous generation of diesels.

Thanks for the correction Mike. Always happy to learn something.