There are two groups of car owners these days when it comes to oil changes. One group is old school: use dino oil, change it every 3K miles, end of story. The other group is more modern and incorporates advances that have been made in oil technology: use high quality synthetic oil which is better for your engine in every way and enhances efficiency to varying degrees depending on the engine and its condition, use oil analysis to first determine exactly how long you can use that oil before changing it and then after that, enjoy the rest of the future 1) saving your time and efforts as you change your oil less often while keeping your engine in superior shape 2) saving your money because when you total up the cost of one year's worth of dino oil changes vs. one year's worth of synthetic oil changes with extended drain intervals, you notice that you save a few bucks 3) and for those that it matters to, save the earth as there is much less used oil to be recycled or burned off during disposals.

There's more than enough room for both parties to co-exist. The former also make sure big oil's wallets never run dry.

To provide you with an exact answer to your question, the higher lead level is due to the extended interval of use you just went through. I experienced the same thing on my 300SD also with Amsoil 15W-40 Heavy Duty Diesel and Marine Oil and when I performed a 3000 miles oil change after that with regular dino oil, my oil analysis results went back to what was considered "normal." Also, your use was extended too much. You allowed the soot level to rise above 2% as Brian Carlton pointed out which isn't good. I'd say you should try your next change at 8000 miles and see what happens. At least you now know that 7000 miles is a bit too early to change the oil and 9500 miles is too late. Another thing you can try is what I do on my car, something I learned of after going through what you're going through. My 300SD goes through the same oil for 8000 miles, but I perform a filter change at 4000 miles and top of the oil.

And oh, your bearings aren't wearing out faster than normal. Just check out the tin level... it is normal and so indicative that your bearings are fine. So relax!! :)

Man, looking back at your analysis results, I see that your engine is so clean burning it makes the good old bullet proof OM617 in my 300SD look like dinosaur age stuff. Firstly, you can't dare use your oil for that long on a 617 and still have the soot level at around 2%. Secondly, Your TBN is still very high at nearly 10,000 miles. Ha, in a 617, all the acids and by products of inefficient combustion would have driven that TBN way down by that mileage. :P

What engine is that? Model, year, displacement, turbo/NA?

I'm going to put my $.01 in. I change the oil in my 91 300D about every 1000 miles. (listen, I hear people fainting.) Why you ask, because my round trip to work and back is about 3 miles. Maybe a trip to the bank one time a week which is about 4 miles, then to the food store one time a week which is about8 miles. This comes up to about 27 miles a week. All short trips. Then one time a month, I take it out on the Interstate for a good tune-up. Another 3 miles/month. That comes out to about 111 miles per month. Now with misc trips to station for fuel, or run out to get something for home repair, etc, I drive maybe 300 miles per month (less than 1 tank of fuel). Now we are up to a little less than 1000 miles in 3 months. Mostly short trips. How many still think I am crazy? Every car needs the oil changed at a different interval depending on the type of driveing it gets.
Have a GREAT Thanksgiving.

First let me say think you for all the input. Now let me answer a few questions as for the car it's a 92 300D 2.5L OM602 with ~116,000k on it now the Oil changes prior to this test were not tested. I skipped the change at ~103k. I had the car in a shop that I trust to tell me if I missed any preventive items and a 100k walk through. I decide that I wanted to do the sample my self to ensure it was done my way. From my personal view I feel that I can use science to optimize the life and use of oil for my car. Blame this on the aircraft maintenance I did for years, it twist the mind I was even in charge of aircraft reliability via analysis in an earlier roll. So this is why I must complete a full test cycle to understand how my engine is operating. I have planed two more tests to complete this journey I think based on the information and pervious test info I will go to 7000 for the next tests. I have pushed the upper limit I have tested at a lower limit and now I’m shooting for a constant safe value. I think if I do two tests at 7000 this should give me an idea that the engine can hold the numbers. I then will do a check every 28k make sure the engine is still healthy. I am open to you ideas I’m not an expert in this area.

Whata waste, do you also roll the windows down and put the a/c on max?

have you considered buying a honda/bicycle/pair of walking shoes?

I cringe a little too when I hear about things like that, I try to save the big vehicles for the jobs that really need them.

However, I'd avoid being too crass without knowing the situation. Many people out there have limited mobility due to medical conditions like diabetes, heart conditions, injuries, etc, for whom a 3 mile round trip might as well be to Antarctica and back. I just try to give people at least a little benefit of the doubt.

peace,
sam

Just had my '98 E320 in for a "A" service - basically change 8litres of oil and a new filter, plus a few checks that required nothing to be done. Cost C$160.00 at MB Dealer. Last "B" service cost over $300.

But, the FSS (Flexible Service) now says next service is in 15000 km. I have oil changed once per year wjhether it needs it or not ;) We only do about 10k km a year.

These dealer services are a rip off, but they do help on resale value and when trying to negotiate with MB on "goodwill" (have had two rust repairs worth $3000 done on "goodwill"!).

But to get back to subject, a newer MB with Synthetic Oil goes for 15k km (9+k miles) between services.

Or their commute would put them in such danger by being a pedestrian that its safer to be in an auto.

Agreed its bad for the car for short trips...but the oil change interval sounds reasonable for the very little the engine actaully gets warm.

You guys are right, sorry snoopy for being an insensitive jerk... I guess I've been on edge since they decided to cancel Arrested Development.:mad:

I liked that show, especially that W126.;)

Snoopy, do you take your car out on the highway for an Italian Tuneup? All of those short trips aren't good, and I'd think your car really does need it. Read about the Italian Tuneup here http://engine.articles.mbz.org/diesel/italian/