sludge
 

how long and under what condition does a oil filter clog? Will it bypass? If clog, will motor sludge quicker?

thank you

Never seen one clog. Using Mobil 1 in a modern Mercedes probably not till almost double the recomended intervail of 13k miles.

just out of curiousity, why are you asking?

tom w

I wouldn't go quite that far. It's true, that new generation MB's (non AMG), equipped with the M272/273 engines have scheduled service intervals of 13,000 miles. They no longer use the Flexible Service System oil level/condition sensor from the earlier M112/113 engines, they just have a simple switch to indicate low oil level. An MB engineer told me that sludging starts within "several hundred" miles of exceeding the mileage interval. Every month my shop does a couple of overhauls due to oil consumption/sludging/knocking issues. Invariably, I find that alot of these cars have had oil changes at 14,000-15,000 mile intervals, so he must have been correct. I've never seen an oil filter clogged though.

That's amazing - like Cinderella having to go home at midnight. It seems like it might be prudent to change more often than 13k.

Interesting, so they really do get every mile out of the oil. I'd love to see a lab report of what the oil looks like after 13k miles.

This surprise me as toyota and honda report no oil change direct reason for sludge remember they class action sued about sludge. Dont know why Mercedes reccommend 13000 miles as oil just cannot hold this much dirt for long. If filter clog i think it just no flow oil is all may be hard to spot even if cut open, yes?

Exactly! That was the whole idea. Back when FSS was first introduced, MB told us that fuel contamination from normal "blow-by" was the major cause of oil breakdown. The oil sensor has the ability to measure to measure the amount of contamination, and determine when the oil can no longer do it's job. That's where the flexible part of "Flexible Service System" comes in. Different driving conditions such as operating temperature, engine load, etc, along with variations in engine tolerances and fuel quality are all contributing factors. The way MB sees it, why change the oil if it's still capable of providing adequate protection?

Makes sense. BMW does 15k mile changes and doesn't seem to have issues. Why pay for extra oil changes? The old 603 can go 6k-8k miles +/- on Delvac 1 according to the lab reports. I don't see why a brand new gas engine shouldn't be able to go 13K.