[BernardFarquart]

I have two higher mileage Benzes, and am going to send in oil samples from both at the next service interval to see what kind of condition the oil (Mobil1 0-40) and engine appear to be in. My 2003 E320 has 119,000 miles, and I am 5500 miles on this oil change, and the 1998 ML320 has 193,000 miles and is about 4500 into the oil change. For reasons of memory conservation, I have been changing the oil on them at the same time, as they accrue mileage at a similar rate. (the E a bit more, because, lets face it, it's a nicer ride.) I usually do the service a bit earlier than the FSS requires, at about 8K to 8.5K miles.

My question is, what mileage will give me the greatest amount of information? Obviously earlier, and the oil will be in better condition, but would I be missing out on getting data that might be relevant? Also, I have read quite a few threads on many forums over the years regarding oil change intervals, and come to the conclusion that short intervals, with a high quality synthetic are not only unnecessary, but may be detrimental.

Any thoughts, relevant experience?

 

[Darkmann]

I did mine on the E at 13K when I first purchased the car in 2001 and the result basically pointed that the oil was still protecting as desired. I never bothered a retake after that. I think that anything under 10K is too early - most cars today go at least 5 - 8 k between oil changes. Heck, even my old 1996 Z Twin turbo call for 5.5 K oil changes. I'd say 10K since that is MB's current set point for oil changes. Let us know how it turns out.

 

[binuya]

short intervals, with a high quality synthetic are not only unnecessary, but may be detrimental.

Any thoughts, relevant experience?

The only detriment would be to your wallet. I do Blackstone analysis on my vehicles and I look for trends as opposed to reacting to individual OA's. Recently, my E300 OA came back with elevated iron levels, and this was on a run with 5k miles. Next OCI I ran to only 4k miles and OA came back with normal iron. Next time back up to 5k miles and all is well, so it could have been a particle streak or something in the way I was driving (i.e. jackrabbit starts on a cold motor), but regardless, I was informed in a way that I could take action. (This car is run with Delo 400, BTW)

Another thought you might consider is to take a sample, but not change the oil yet until you hear back from the lab. (Blackstone reports give a recommendation as to how much longer you can run the oil, provided it checks out okay in all other aspects) On my E300, most of the time they tell me to run it out another 1k-1.5k miles. I usually stick to my 5k miles, but it's good to know how much life is left. So there's a couple thoughts on OA's.

 

[BernardFarquart]

Thanks for the replies, I think I will let it go to 10K miles, and do the analysis for a few times in a row, to see if it is consistent. I use almost no oil in either engine, so I have high hopes for the results, just getting curious as the mileage ticks up.

I am using a sample kit from WIX, (#24077) that you mail in. my cost is under $15.00, so it's not too much of an additional expense.
__________________

 

[43sqd]

For $25, you should consider Blackstone.

Gas Engine Sample Report 1