Oil consumption appeared

[Nolwyn]

Hello,

I went on a roadtrip with my Z4MC all around central Europe, implying some hard driving.
I did an oil change 3000kms before the roadtrip with oil to the max. Checked the level before the roadtrip last week, still at max. The roadtrip did imply some hard driving.

In the middle of the roadtrip I checked my oil level and it was slightly under maximum. Today it's between min and max.

I don’t see any leak and starting to be really worried about this as S54s dont burn oil normally and it was never using any before.

It's at 118k kms and worried that my hard driving during the trip damaged the engine.

 

[TomK]

I doubt it's your hard driving, my car pretty much spent it's last 50k kms between 4-8k rpm at full throttle and does not use any oil, like most S54, as you say.
Something must be up with it though. Good luck.

 

[Ed Doe]

Stupid question but is it being checked under the same circumstances?

ie. same parking spot (ie. you're parked on the same presumably flat ground, or at least the same angle of ground if its the same parking spot!) , same oil temp, similar ambient temp,?

 

[Nolwyn]

Stupid question but is it being checked under the same circumstances?

ie. same parking spot (ie. you're parked on the same presumably flat ground, or at least the same angle of ground if its the same parking spot!) , same oil temp, similar ambient temp,?

Hello

It wasn’t really during the roadtrip but now I've tested in the same conditions as 3000kms ago and it definitely used some oil. Like I said it was at the max, now it's slightly above the middle.

 

[Nolwyn]

I doubt it's your hard driving, my car pretty much spent it's last 50k kms between 4-8k rpm at full throttle and does not use any oil, like most S54, as you say.
Something must be up with it though. Good luck.

Yup that's what I thought... When I was using it before it was also driven hard and never used any oil.

 

[Mr Tidy]

That does seem unusual for an S54. Mine never needs topping up between oil changes that tend to be about 8K miles apart even though it has done 96K miles now and often gets driven as intended!

Maybe there is a slight leak somewhere? When mine had an Inspection Service on 77K the cam-chain tensioner was sticking and leaking, so a new one got fitted.

 

[Nolwyn]

That does seem unusual for an S54. Mine never needs topping up between oil changes that tend to be about 8K miles apart even though it has done 96K miles now and often gets driven as intended!

Maybe there is a slight leak somewhere? When mine had an Inspection Service on 77K the cam-chain tensioner was sticking and leaking, so a new one got fitted.

I have checked for any leak and couldn't find any. Right now I'm probably thinking about valve stem seals or worse, piston rings. I'll try to do a compression test and maybe oil analysis.

 

[Jimbo76]

I have checked for any leak and couldn't find any. Right now I'm probably thinking about valve stem seals or worse, piston rings. I'll try to do a compression test and maybe oil analysis.

Don’t overthink this…do an oil change and run it for a while, see how it goes. These engines are not prone to burning oil!

It’s a litre between minimum and maximum so depending on how you’re viewing the dipstick it could be less than half a litre…allowing for the car not sitting perfectly flat etc etc

 

[Nolwyn]

I finally got home, parked the car in my garage where it was right before the roadtrip. I've let the car sit overnight and checked the oil this morning, exact same conditions as last time. You can't really see it on the picture but it's at 2/3rd of the gauge. So exact same measurements conditions as 8 days ago: my car used about half a liter during the 3000kms. It's not much oil consumption but it's still there. And that's enough to concern me about it. I'll do a compression test and check for leaks. If nothing's wrong, I will ask my local specialist to have a look. Maybe worn valve stem seals or something with the PCV...

 

[Nolwyn]

I finally got home, parked the car in my garage where it was right before the roadtrip. I've let the car sit overnight and checked the oil this morning, exact same conditions as last time. You can't really see it on the picture but it's at 2/3rd of the gauge. So exact same measurements conditions as 8 days ago: my car used about half a liter during the 3000kms. It's not much oil consumption but it's still there. And that's enough to concern me about it. I'll do a compression test and check for leaks. If nothing's wrong, I will ask my local specialist to have a look. Maybe worn valve stem seals or something with the PCV...

I managed to free up some time this evening to look it up and... results were not good. I checked the PCV valve and everything was fine. I started doing a cold compression test (easier to spot compression differences than hot). First 2 cylinders were good, more than 170psi, so I was quite happy. When removing spark plug from cylinder 3, I noticed the thread was full of oil (not good), and it didn't miss, compression was quite lower (but tolerable). Cylinder 4, same story, even more oil and compression was even lower: 150psi. 5 & 6 were quite the same story, between 150 and 155psi.
I've tried to squirt some oil on cylinder 6, and compression jumped up quite noticibly.

The car is still running fine but knowing that now, I guess it's going to be down for a moment