Oil consumption only on highway

[Medeng1]

Good afternoon.

On weekend I met up with sudden oil consumption problem, while I was riding nearly 200 kms ahead and back cruising on highway at 140 km/h. Car showed me a message, that possibly low level of engine oil. Had stopped car and checked on dipstick. For sure, level were on low mark. Luckily, I had extra liter of same oil. Added 0.7 liters.

While riding in city everyday (30-50 kms/day), short distances, car doesn't ask to add oil. I mean, change to change - don't need to add oil, it stays on the same level. But when I ride on highway above 2.4k rpm, it asks. It's the second time with that kind of situation on highway.

Engine sounds good, no rattle or knocking or whatever sounds. I took off engine cover from the bottom - it was almost clean. No smoke on startup or even at load, exhaust is pretty shiny as petrol engine. I guess DPF blocks everything.

I read about piston rings, but as I understand, if the problem in them it would burn all the time, not just on highway?

Guys, can you tell me probably what's happening with my car?

[Georgeandkira]

Year and miles, please. You have a diesel, no?

We grew up hearing that a stuck open PCV system could result in "highway oil consumption".
We have no diesels in No. America but I believe they have the same PCV system as the petrol engines.

Was your 0.7 liter of makeup oil done towards the end of the oil change interval?

Do you know what oil you were running? Some have a higher "Noack number"; essentially an oil's tendency to evaporate.

[Medeng1]

Forgot to mention, sorry... P2 platform 2.4D 120 kW. MY2008. Euro 4. 180k miles.

Changed pcv membrane, as it’s were leaking. If I’m not going on highway, it doesnt require to add oil between changes at all.

Since I have a car, I always change oil by myself. Liqui moly 0w30 A5/B5 as Volvo says.

[old onions]

Almost exactly the same issue and I have a 2.4 140 bhp petrol engined car with 120k miles.

I do about 8,000 to 10,000 miles pa (well I did before the pandemic) and it will easily go with additional oil between its annual service.

However whilst taking the family on holiday and doing more motorway and higher speed miles I have had the "low oil level" warning on the dash come on twice now. On both occasions I checked the oil level at home before setting off and it seemed fine, so I was quite puzzled.

As a result I now carry a litre of the A5/B5 0-30W oil in the boot for topping up.

[Medeng1]

But it’s not a way out of the situation However, topping up a 1l of Liqui moly 0w30 every 400 km or so on highway is not the best thing.

I really want to believe, that it’s turbo...

[barrybritcher]

is there anything on the floor?

I had to tighten the connection from the pcv catch can to the block as it would weep out when been on a long run

[Medeng1]

The bottom engine cover is clear. Almost no leaks at all, except from vacuum pump. But it couldn’t lose 1 liter from that place after ~250 km run. Would be everything oily.