It's a long story but I thought our friends at Castrol had left some debris in a brand new bottle of oil! Till I realized it was probably from my own oil catch pan... Let me explain. I finally found a place for all that 0w-40 Syntec I bought last Christmas. It's time to replace my wife's 2001 TT so I bought her a 2013 BMW 328i Convertible with 35k miles on it. Of course the on-board computer is warning me the oil change was due two months ago so first thing I do is buy a filter and drop the oil. Didn't look too bad but I suspect this car's been getting nothing more than the dealer recommended 10k changes. I know, I know, I should have pulled an oil sample! But here's the funny part, nothing in the owners manual tells me what the oil refill capacity is and this beast has no dipstick so I'm searching the internet for the capacity. Most say 6.5 qts. but some say 7. Hummm... so I decide to dump the old oil back into the 5 qt jug and measure how much I drained. I had checked the electronic oil level and it was full before I did the change. Sure enough, when I have the jug full, there is still about a qt. left in the pan. So I grab a fresh qt. and in she goes. Now I dump the remaining oil into the single qt. bottle and it comes a little shy of filling it up. So I conclude the capacity is 6 qts. The electronic measurement is now just slightly below max so the 6.5 qt. guys are right on this rig. I then dump the old oil into my 5 gallon recycling can and notice something in the Castrol single quart bottle! shaking it upside down and out comes a leaf! Holy smokes I think, I just dumped oil from that bottle into my nice new engine and it had a crud in it! Man, won't the guys on BITOG love to hear about this!!! then it dawned on me, it's probably from dirty old oil pan... Ugh!