high mileage expectation




UOA report
Calcium + magnesium levels comps being vastly different suggest lab is comparing to a different reference oil chemistry: older SN vs. newer SP formula.
Then we look at the viscosity analysis...
your 4kMi oil sample has derated to W30 viscosity range of 11.08.cSt.
Consider using this oil for less distance (3kMi?) or find an upgrade that better meets your hot TT GDI needs.
I suggest you consider premium MB Approved PAO lubricants of your choice.
Did you notice an improvement in engine response right after clean oil service and for 500.Mi ??
That's from phasers reacting to better oil pressure of fresh oil.
Last edited by CaliBenzDriver; Dec 15, 2025 at 09:49 PM.
There are some seals on the front of the turbo engines.. it's an easy repair and it must be done or you will cause the engine to get dirty and dirt is the engines enemy as corrosive chemicals stick the plastics in the engine. Clean your engines every years and repair and oil leaks. If you live a cold or extreme hot, all cars go through extremes especially if they are parked outside.
The current line as well as the previous years Benz engines are well built but other parts of the car will fail but it's all up to the owner to take care of the car. I've had a few Benz already and never had an engine problem.
Cali - the Blackstone report was a sample of (my third sequential) oil change of Pennzoil Ultra Platinum (PUP) Euro SP 5W-40. I have very recently changed back to Mobil 1 Euro 5W-40...as they came out with a "SQ" rating (!). The price point is way more affordable compared to PUP Euro 5W-40 via Amazon or Motul. I found it very interesting that the PUP Euro 5W-40 sheared out of viscosity in just under 4600 miles of daily (100 mile/day) commute. 90% highway with 10% stop & go/city miles. I'm careful to be warmed up before "hot-*******", but my daily commute only affords about three usable passing zones. All that to say, I'm not beating up my 158,000 mile C450...but hopefully spur her enough to keep carbon deposits at bay (with a straight diet of Shell V-Power 93). Hopefully the Mobil 1 SQ can yield better results for staying in viscosity.




Cali - the Blackstone report was a sample of (my third sequential) oil change of Pennzoil Ultra Platinum (PUP) Euro SP 5W-40. I have very recently changed back to Mobil 1 Euro 5W-40...as they came out with a "SQ" rating (!). The price point is way more affordable compared to PUP Euro 5W-40 via Amazon or Motul. I found it very interesting that the PUP Euro 5W-40 sheared out of viscosity in just under 4600 miles of daily (100 mile/day) commute. 90% highway with 10% stop & go/city miles. I'm careful to be warmed up before "hot-*******", but my daily commute only affords about three usable passing zones.
All that to say, I'm not beating up my 158,000 mile C450...but hopefully spur her enough to keep carbon deposits at bay (with a straight diet of Shell V-Power 93).
Hopefully the Mobil 1 SQ can yield better results for staying in viscosity.
If you want to cheat a little... simply change oil at 4000.Mi before too much visvosity is lost to polymer shearing.
Viscosity translates into pressure
Oil Pressure relates to spraying Rpm.
This is how viscosity relates to effective cooling besides bearing protection.
Last edited by CaliBenzDriver; Feb 11, 2026 at 08:24 PM.
Redemption was that the AOS was indeed plugged up pretty good - and the crankcase breather pipe ALSO had stress cracks prior to the wrestling session that were not immediately visible during prior "on lift" inspections. I had previously experienced intermittent "popping" of my engine oil dipstick (only about an 1/8' to 1/4" out; maybe 50% of the time I would check each week), accompanied by a faint "oily" smell after immediate shut down after the daily commute. I had previously associated the oil smell to an instance of an oil change gone horribly wrong - where the shop (a reputable one, not Jiffy Lube) happened to leave off my engine oil cap on top of the motor, and shut the hood. The story was one tech distracted the other while he was finishing up. A longer story for another time, but needless to say the car survived, never threw a light on the dashboard despite driving 10 miles home without a cap & blowing about 1/8th of a quart ALL OVER the underside of the hood & bathing the passenger side turbo, suspension, etc. The shop gently power washed top, bottom and sides - but on the ground and not up on a lift...so I figured there was a residual mess. Until we did those plugs and found the oil under the air filter element. Things that make you go "Hmm" and "Dammit"...
Thanks for reading

I worry about what happens to my plastics in the engine 15-20 years from now :/
The Best of Mercedes & AMG
Oh great, another thing to be paranoid about..
..well, my next oil change is also my 20k interval for air filters, I'll poke around when I'm there, and watch my dipstick. (to be fair, at 167k miles, I burn 1/2 qt every 5k, so it's much better than a BMW I had once, a quart every 1500-the e46 still made 334k before rust won, but I always had spare oil in the trunk). The air filters for this car are on the small side, I don't go to 30k.I follow the service book for most things, usually slightly ahead of recommended interval.
I just did a full fluids exchange...Engine coolant and intercooler circuit. Front and rear diffs. Transmission service (yes, I debated this, I'd done it at 70k, but it appears to have slightly smoothed shifting, so no disaster) Brake flush. All at an indy, all in just under 3K with a wheel alignment included. I do as much work as I can DIY, but the trans wasn't something I was going to tackle-the price of failure is too high and the cost to have it done by someone who'd done it before not too bad-I read the instructions and viewed U of Youtube....nope.
My current minor battle is a flashing "gas cap loose" and minor evap leak obd code. I've ordered a new cap and hopefully that fixes it. Second CE in the car's history, the first was the oil solenoid, for which "the hack" was done.
In the past, I had the vacuum pump one way valve fail, but did that replacement with an ebay part....boost happy again.
I'll watch the plastic....I too occasionally get a whiff of oil when parking but can't find any real leaks.
Last edited by speedlaw; Apr 1, 2026 at 10:55 AM.
I also agree that having the transmission serviced by the professional (Indy) shop is the way to go. My next interval is 180K, so maybe in 9 months from now (Dec 26')? Last time was $600.
My engine oil consumption is also right around 1/2 quart for 5,000 miles. It was double that with the plugged AOS/cracked breather pipe combination though.
I wish Mobil 1 would make their version of Valvoline Restore & Protect as an MB 229.5 approved. However, it seems the V R&P is only available as API "SN" rated, plus 5W-30 is currently the thickest offering.
Seems like the oil manufacturers are finally just catching up with synthetic "SQ" rated oils that are correct/best for our twin turbo applications about 10 years too late.





