I don't think cost is the issue. I think the purpose of the reports is to objectively determine the potential effects of changing oil at various intervals. He's basically being the guinea pig for the rest of us.

I have always thought synth oil at a 10,000 mile interval or dino at a 5,000 mile interval would be fine. Now I am convinced of it.

3,000-mile oil change intervals appears to be for severe-duty vehicles only.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

I had my wife's 98 Avalon's oil sent out to Blackstone when using M1 5w30 Synthetic at around 5500 miles. They recommended a 5k change so I switched back to dino M1 5w30 and am shortening the interval to 4k. The large extra cost for syn didn't seem worth it to me if I couldn't run any longer OCIs. I had the same logic in my mind when switching the Avalon over to syn but it seems her car can't do 10k OCI.



To reply to Kenny, the report costs roughly the same as one oil change. So say you get a report and they tell you that your car can run another 2k miles per oil change. You will make up the cost on the report pretty quickly (this assumes you own the car for several oil changes). If one can indeed run a 17k OCI and you were changing it out at 5k, that is 2.5 oil changes you just saved in money and hassle of the oil change, so no it does not necessarily cost more to get an analysis. In my case it did but I will no longer run synthetics in the wife's car.

__________________
2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

Interesting, and thanks for sharing. So maybe I'll stick to my current 5K interval with dino? The only way to be sure would be to send a sample in to Blackstone at 5K and see what they say...

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Mobile One, see post #7 for more details.

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Never a dull moment at Berry Hill Farm.

Saving money on lengthened OCIs isn't really the issue here. We were interested in proving that synth's lube quality can go the distance while still taking care of the engine's lube needs. Sidebar benefits of an oil analysis would include discovery of latent air filtration, combustion and cooling system issues. None on this vehicle but I did discover through Blackstone that I had an air filter/intake tract issue on my bulldozer.

BTW, that's my daughter's car. She's a mechanical engineer.

__________________
Never a dull moment at Berry Hill Farm.

Granted I only did one analysis and I believe I had just switched to synthetic. Perhaps I should have ran another batch of synthetic to see what the report then said. I believe some metal counts were high which is why the recommended a 5k OCI. Perhaps it cleaned everything out and the gunk/deposits accumulated in the oil on the switch to syn. Guess I'll never know now...

You are right. The only way to know for your car is to send out a sample.

__________________
2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD