The Curious Case of the Increasing Oil
10-11-2022, 02:40 PM
#1
Instructor
Thread Starter
The Curious Case of the Increasing Oil
Hi all,
I've got a 2015 Cayenne Diesel, about 138 000 kms on it. Runs great, everything is amazing, and I change the oil regularly.
Last oil change, as per normal, I used Mobil 1 EPS (Porsche C30 spec) and filled it to the correct amount. Reset the oil change interval, and everything was tickety boo.
Drove it for about 3000 kms, when suddenly I started getting an error that I had too much oil, and I should see a workshop immediately. Almost like the oil had expanded from heat, but failed to contract when cooled. Has any one ever experienced anything like this? The display on the dash shows that my oil is filled to max amount, but how could oil expand in volume as it ages?
I've got a 2015 Cayenne Diesel, about 138 000 kms on it. Runs great, everything is amazing, and I change the oil regularly.
Last oil change, as per normal, I used Mobil 1 EPS (Porsche C30 spec) and filled it to the correct amount. Reset the oil change interval, and everything was tickety boo.
Drove it for about 3000 kms, when suddenly I started getting an error that I had too much oil, and I should see a workshop immediately. Almost like the oil had expanded from heat, but failed to contract when cooled. Has any one ever experienced anything like this? The display on the dash shows that my oil is filled to max amount, but how could oil expand in volume as it ages?
10-11-2022, 04:42 PM
#2
Motor oil doesnt expand/contract a lot, so unless you put an amazingly exact amount to set off that sensor, its prob not hot oil. If you did manage to do this, the error would go on and off. Off when cold, on when warm and would've happened soon after your oil change, not 3k km later.
Guessing your sensor is bad or another fluid has joined your motor oil in the crankcase. Drain and check the color or get a dipstick.
Guessing your sensor is bad or another fluid has joined your motor oil in the crankcase. Drain and check the color or get a dipstick.
10-11-2022, 06:47 PM
#3
Rennlist Member
Oil definitely doesn't expand, so either your sensor, or you're leaking coolant in your engine. If you're somewhat handy, it might be wise to send in a used oil sample: https://www.blackstone-labs.com/services/pay/
It's relatively cheap and can help detect issues. If you don't want to wait for an oil change, you can just loosen the drain nut all the way but continue to hold it perfectly in place so that it blocks the hole. It's messy, but you'll get a small stream of oil coming out. That's what I did.
It's relatively cheap and can help detect issues. If you don't want to wait for an oil change, you can just loosen the drain nut all the way but continue to hold it perfectly in place so that it blocks the hole. It's messy, but you'll get a small stream of oil coming out. That's what I did.
10-11-2022, 08:38 PM
#4
Rennlist Member
Does the oil smell a bit like Diesel fuel?
Could be a bad injector/s dumping fuel instead of spraying.
Could be a bad injector/s dumping fuel instead of spraying.
10-11-2022, 08:47 PM
#5
Instructor
I agree with BrendonSF. You can usually tell by removing the oil filler cap and looking around for any creamy, light-colored sludge buildup. Hope this is not the case.
Best of luck. Keep us posted.
Best of luck. Keep us posted.
Oil definitely doesn't expand, so either your sensor, or you're leaking coolant in your engine. If you're somewhat handy, it might be wise to send in a used oil sample: https://www.blackstone-labs.com/services/pay/
It's relatively cheap and can help detect issues. If you don't want to wait for an oil change, you can just loosen the drain nut all the way but continue to hold it perfectly in place so that it blocks the hole. It's messy, but you'll get a small stream of oil coming out. That's what I did.
It's relatively cheap and can help detect issues. If you don't want to wait for an oil change, you can just loosen the drain nut all the way but continue to hold it perfectly in place so that it blocks the hole. It's messy, but you'll get a small stream of oil coming out. That's what I did.
10-12-2022, 07:07 AM
#7
Instructor
Hi,
any engine codes ?
Have you had any problems with your Diesel Particulate filter ?
Could be caused by DPF regenerations not completing properly.
I had some problems with my DPF last year and I learned that the car does a DPF regen about every 400 miles or so.
The engine needs to be up to full temp for the regen to start automatically, then it injects and burns diesel to get the dpf up to ridiculously high temps, then you need to drive at constant speed / revs for a good few miles, about 15 mins at least.
The problem comes if you are doing short journeys, the DPF regen process initiates but if your journey is too short the DPF regen fails and the extra diesel gets dumped back into the sump increasing the oil level !
If short journeys continue you will begin to notice the increase in oil level.
It could also be that after 138K miles the dpf has reached end of life.
Worth a try taking it on a nice 30 min highway drive every now and then.
Good luck
any engine codes ?
Have you had any problems with your Diesel Particulate filter ?
Could be caused by DPF regenerations not completing properly.
I had some problems with my DPF last year and I learned that the car does a DPF regen about every 400 miles or so.
The engine needs to be up to full temp for the regen to start automatically, then it injects and burns diesel to get the dpf up to ridiculously high temps, then you need to drive at constant speed / revs for a good few miles, about 15 mins at least.
The problem comes if you are doing short journeys, the DPF regen process initiates but if your journey is too short the DPF regen fails and the extra diesel gets dumped back into the sump increasing the oil level !
If short journeys continue you will begin to notice the increase in oil level.
It could also be that after 138K miles the dpf has reached end of life.
Worth a try taking it on a nice 30 min highway drive every now and then.
Good luck