Ash fouled plugs at 85k (10k late tune up) s60 2.5t

drjackmd · Post by **drjackmd** » 20 Nov 2019, 22:03

SEE IMAGES OF ALL 5 FOULED PLUGS pulled from 2012 Volvo s60 2.5t at 85,085 miles. I purchased the (OEM Volvo) plugs for the 75,000 mile tuneup but did not perform it because a fellow mechanic (a very experienced one, one with an advanced engineering degree) mentioned that he has seen many plugs perform way beyond there life expectancy. One example was still a daily driver at 309,000 miles on the odometer. My car was running great at the time, so, let's just say that the challenge intrigued me to participate. Three months and 10,000 miles later, I changed the plugs today because I felt hesitation during an acceleration attempt from 70 to 90 while about halfway through yesterday's 350 mile road trip. Never experienced any hesitancy from this car since I purchased it (MAR17) with 49k on the ODO. Acceleration has always been more than satisfactory. Immediately after the plug exchange, I checked the oil (which I had changed last night, mobil 1 5w30 full synthetic), then I started the engine and idled it up to operating temp before going on a 45 minute drive in moderate traffic. Upon entering the highway, opened her up and she immediately sputtered before I noticed the diesel-like cloud of smoke I left behind. (Again, two things I've never seen this car do since yesterday.) After that I drove conservatively and the rest of my trip was uneventful. No engine codes before nor after the exchange. The only other thing I did before yesterday's road trip was fill up an almost empty tank with 87 octane from BP. Up until this point I was on high octane only, and my gas over past 2 years was purchased almost exclusively from Costco. I do not put additives in my fuel, nor engine.

The concerns I have:
...are my pistons and/or rings failing?
...is costco gas bad for my car?
...is there a problem with switcheroo from high octane to 87 octane fuel?
...my car does not leak oil but it does burn oil, however the oil burning has been inconsistent. One oil change cycle I drove full 7500 miles without need for a single drop of oil, then next cycle I'm down a half a quart in first month. In September I drove 700 miles from VA to MI. Oil was at top line at start and exactly the same at when I arrive in MI. However, on the 600 mile way back, 300 miles in I check the oil and I was 2 quarts down. The only difference I can think of is that the way there was mostly downhill and the way back was a lot of large uphill roads through West Virginia.

So, who's can help me find my needle in my haystack? I'm heading to D.C. tomorrow for the weekend so I will surely update this post with any new symptoms or praises.

P.S. I don't trust my local dealer with my coffee. Definitely don't trust them with my car.

Post by **RickHaleParker** » 21 Nov 2019, 10:27

Light Brown or White?

Ash Fouled - Light brown deposits encrusted on the side or center electrodes or both. Derived from oil and/or fuel additives.

Deposits - The accumulation of deposits is influenced by oil leakage, fuel quality and the engine's operating period.
Deposits come from:

Fuel - Carbon, Lead, Bromine
Lubricating Oil - Carbon, Calcium, Sulphur, Barium, Zinc
Others - Iron, Silicon, Aluminum, etc.

drjackmd · Post by **drjackmd** » 05 Dec 2019, 11:01

The deposits were white.

UPDATE after 450 mile roadtrip...
FILLED UP ON 87 Octane from BP before leaving. Didn't have any issues with acceleration. No hesitation. No smoke. Oil level was still full upon return. Average MPG was 28, mostly highway miles.

Filled up with high octane from BP upon return. And now just added a 1/2 quart yesterday after about 190 miles of city driving.

I can definitely feel more power with the higher octane fuel, but really not life changing. Could the high octane fuel be causing the oil to burn?