BMW M3 Forum (E90 E92) - View Single Post

m6pwr · 07-06-2013, 12:15 PM

Hi Blankstar. I'm afraid I can't be of much help re problems with the car itself - - have to leave that to the dealer and their diagnostics. BUT, you've only had this one uoa that MAYBE shows high fuel dilution. I would just try to keep an eye on it with the next couple of uoa's - - try to get a handle on what's normal for your car.

I'm too new to the S65 engine to know whether or not fuel dilution is usually present to any degree - - and part of that is due to using Blackstone for many, many years on other past M BMWs.

The way the sample is drawn can definitely affect the resulting report. If the car has been jockeyed around by the dealer with a lot of idling just prior to drawing the sample from luke warm oil, it would I expect show more than normal fuel dilution. FWIW I did a uoa on the first 1200 mi "break-in" drain (done at the dealer) and the uoa showed 1.5% fuel dilution. That's a lot for just 1200 mi., but I bought the M3 from dealer stock with about 50 mi on the clock (lots of short test drives?). Maybe high fuel dilution is normal in the M3.

The fuel itself in the oil does no damage. It's what it does to the oil that has to be watched. Your uoa still looked ok to me in that regard. I was told some interesting things by a lubricant engineer who worked for Castrol and had direct experience with TWS. He said the Castrol-supported Audi and VW teams at the 24 hr Nurburgring race used TWS 10w60 even though their normal service fills were 5w40. They did it to counter the expected fuel dilution over the course of the long distance race. I think BMW expects fuel dilution over the course of extended drains on M engines and maybe that's why they spec 10w60. The lube engineer also said that some fuel dilution is good. It counters the effects of oxidative thickening of the oil over an extended drain.

Hope this helps. Sometimes I think doing uoa's is counterproductive. People get too wound up over one report when copper is high, or iron spikes a few ppm, or 3 or 4 ppm lead shows up. Sometimes ignorance is bliss.

07-06-2013, 12:15 PM	#89
m6pwr First Lieutenant 38 Rep 374 Posts Drives: '14 335i M sport Join Date: Oct 2008 Location: San Diego, CA iTrader: (0)	Hi Blankstar. I'm afraid I can't be of much help re problems with the car itself - - have to leave that to the dealer and their diagnostics. BUT, you've only had this one uoa that MAYBE shows high fuel dilution. I would just try to keep an eye on it with the next couple of uoa's - - try to get a handle on what's normal for your car. I'm too new to the S65 engine to know whether or not fuel dilution is usually present to any degree - - and part of that is due to using Blackstone for many, many years on other past M BMWs. The way the sample is drawn can definitely affect the resulting report. If the car has been jockeyed around by the dealer with a lot of idling just prior to drawing the sample from luke warm oil, it would I expect show more than normal fuel dilution. FWIW I did a uoa on the first 1200 mi "break-in" drain (done at the dealer) and the uoa showed 1.5% fuel dilution. That's a lot for just 1200 mi., but I bought the M3 from dealer stock with about 50 mi on the clock (lots of short test drives?). Maybe high fuel dilution is normal in the M3. The fuel itself in the oil does no damage. It's what it does to the oil that has to be watched. Your uoa still looked ok to me in that regard. I was told some interesting things by a lubricant engineer who worked for Castrol and had direct experience with TWS. He said the Castrol-supported Audi and VW teams at the 24 hr Nurburgring race used TWS 10w60 even though their normal service fills were 5w40. They did it to counter the expected fuel dilution over the course of the long distance race. I think BMW expects fuel dilution over the course of extended drains on M engines and maybe that's why they spec 10w60. The lube engineer also said that some fuel dilution is good. It counters the effects of oxidative thickening of the oil over an extended drain. Hope this helps. Sometimes I think doing uoa's is counterproductive. People get too wound up over one report when copper is high, or iron spikes a few ppm, or 3 or 4 ppm lead shows up. Sometimes ignorance is bliss. __________________ '14 328d, '13 M3 ZCP, '12 535i, '11 335d, '09 Z4 DINAN Stage II, '05 330i ZHP, '05 M3 ZCP, '02 M3, '91 328i, '90 535i, '88 528e, '88 M5, '87 M6, '95 Z3, 95 M3, '93 M5, '87 325e, '89 535i, '86 635i, '73 Bavaria.
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