Green O-Ring residue found in oil... 2000 C2 Cab

As the subject line mentions, my mechanic recently found tiny little green rubber bits in the engine oil when we drained it leading up to IMSB replacement. The bits are very small, smaller than peppercorns in size, more like salt bits used in salt grinders. Some of the bits were clearly rounded such that it was obvious they used to be part of of a complete o-ring. Also, my car has a bit of inconsistent chain rattle that goes away shortly after start up. Sometimes it does not make the sound at all, sometimes it does it at start up whether warm or cold. Could this residue we are seeing be associated with the o-rings that come with the Chain Tensioner rail replacement kit? Such as shown here: http://www.pelicanparts.com/More_Inf...05-253-00-M100 This might explain both the rattle I'm hearing, as well as the green bits in the oil. Any insight greatly appreciated...

I think it would be wise to drop the oil pan and check for more debris. There is a screen on the oil pickup tube that may have some particles on it as well. Also, change the oil filter and cut open the old one and see what is in the pleats. Now, are they dropping the engine to do the IMSB replacement? If so, really good time to address the chain rails and chain tensioners, obviously replacing them all. I was thinking about another thread where I thought he said he forgot to order the replacement O-rings for the chain tensioners and they were green as well. I think. Hope it all works out okay.

Oil Filter has been checked. That's were we actually found the green bits. We were digging for metal shavings. The engine has been dropped and we are making the laundry list of items to replace. Would really like to make that chain rattle go away, hoping this added effort and expense kills two birds with one stone.

There are a number of green o-rings. Could be from the chain tensioner. It would make sense because of the chain rattle. I would definitely trace down the problem before driving again.

that was my thought on it also^^

Thanks for the pics and interaction. I just got my mechanic on the phone and did an impromptu webinar so we could screen-share and I showed him this thread and we looked over parts online (gotta love technology) and we are both on the same page. We both think these wear items are the likely culprits. The color of the rubber bits we found exactly matches the color of those rings on your tensioner photo, kind of an aqua/bluish/green... I will post pics and findings once we get to that. The parts are ordered and on the way, and he is now back to working on finishing up the Vertex Eternal IMSB replacement install while we wait for the parts to arrive. Was thinking it might be the vario cam solenoid gaskets, as there is some seapage... but he does not think it's wet enough around that area for those o-rings to have deteriorated to the degree we saw. Those are being changed, too. After doing some more poking around in this forum, I think we are barking up the right tree here.

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What are the green o-rings in the background of that picture? Thats the color of the plastic I found in my oil filter. It was a hard/brittle plastic. Thanks.

Those orings fit over the spark plugs tube/chamber in the heads and are between that surface and the valve cover. 20160504_215503_zpsdtci1dms.jpg

UPDATE: Engine is back in the car... We pulled the tensioners and the rings on those looked fine. They were still rubbery and, aside of the little bit of oil on them, looked new. The o-rings under the tensioner guides looked fine, too. Despite the fact that the tensioner guides themselves look completely trashed. New tensioner guides were installed. My mechanic and I are both of the opinion the couple of bits we found (which was not nearly enough to make a complete o-ring) were likely left over from a previous repair. Engine runs quiet, smooth and strong. Work was completed about 1300 miles ago.

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Ummm...those green bits are 100%, without a doubt, from the variocam. If your mechanic didn't know that, I guess it's time for a new mechanic as this is fairly common and well known amongst those that know these cars. You can argue that they are this or that and that the car is running fine (for now) until you are blue in the face. But in the end, it will come back to haunt you...

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I'm not arguing anything. Variocam tensioners were pulled and inspected from each cylinder bank, and and the variocam guides were replaced. No damaged or missing o-rings were found.

My money is on the spark tube orings. Seen in the background of that pic. You can lose parts, or all of one when replacing them. When replacing them. http://www.autohausaz.com/search/pn....FUJbhgodhXsAIg

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Thanks for pointing that out. The rings in the background of that photo look thicker, but they are not in focus, so that is probably why. Do those rings get darker with age? The fragments in my oil were a darker green-blueish color, more like the ones on the tensioners in that photo. The thread really should have been named "Blueish bits found in oil" or teal... I will ask my mechanic if he looked at those when the variocam tensioner pads were swapped. I got nothing more than a single receipt for a new alternator and whatever was vaguely listed on Carfax in the way of service history when I bought the car, so if those can indeed be dislodged or damaged during maintenance I'll take that as an overall positive sign that money was spent on the engine internals in it's past.