Ok guys, in an attempt to prove to you that frequent oil changes are not necessary I'm never going to change my oil again on my two Mercedes diesels.

I will change my filter once per year and top off as necessary. I will use a quality synthetic diesel grade oil. I won't do anything else like oil testing or any tricks. That's it.

The 300D currently has 22kmiles on the oil that was changed 18 months ago. The 240D currently has 18kmiles on the oil that was changed 36 months ago.

I will post my results periodically in this thread. If anything goes wrong, I will report it.

240Joe

Now that's dedication to proving a point

At least it will provide some solid real world testing on the subject.

You don't have any huge oil leaks do you, like two-gallons every 3k miles?

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-justin

1987 300TD, 1987 300TD
2008 R32, 2000 Passat Wagon

Why not get some analysis? It will be a way to confirm or deny your theory.

No leaks. The 300D uses very little oil, but the 240D uses some just because I run it at 85mph all the time. 240Ds use oil at that rpm.

240Joe

Part of my theory is that oil testing is also not helpful in any meaningful way. I'm just going to run them.

These cars are throwaways anyway, so I don't really care if I melt one down.

Heck, some people on this forum blow them up periodically and they're certified mechanics.

240Joe

So I'm expected to believe that your theory has any validity, when you're using a sample of two and nothing to indicate MTBF.

I didn't say that you had to do an analysis to determine when to change your oil. I'd like to see some to see if you're off your rocker.

Bought a 82 300TD that had a new engine at 75,000 miles. The owner never changed the oil or filter.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

I'm not off my rocker. I put about 15kmiles on these two vehicles per year total.

Great info Dmorrison. The car went 75kmiles without oil or filter change....now that's impressive. That filter had to be in full bypass mode after about 30kmiles.

That just proves again, that with a filter change per year, they'll go forever.

240Joe

How are you going to prove that data that you don't collect is not helpful or meaningful?

I too like the dedication. Had a buddy that tried for a few years to kill his VW Fox, never changed the oil. Finally got bored trying to kill it and sold it.

For any good test you have to have a control group and the experiment. I volunteer to change my oil at regular intervals, like every 5,000 miles. Mine literally just turned over 100,000 last night a mile from the house. Such beautiful numbers perfectly balanced 100,001 wife and kids wandered in, I am sitting out there soaking it in...

Now we need an independent verification, so someone in 240Joes neighborhood needs to seal the dipstick, fuel filler cap and the fuel filter, so we can check for any tampering.

Then we need a placebo one. Maybe 240Joe could allow every 5,000 miles a member to take his (other) car away, then either change or not change the oil.

Then a GPS mounted unit on the main test vehicle. And, this is were it should get fun some type of live data feed from it, (not viewable to 240Joe) so we could sit here and monitor critical data when it is underway.

Should be fun and this will undoubtedly start a thread that will be fun to watch.

Let the fun begin.

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raMBow

1999 E300DT Obsydian Black Metallic, Heated Full Leather Parchment options, E2, K2, 136,000+, best 36.5 mpg - GP's 12-04 & 11-12 Zero Stuck
2010 Honda Odyssey - The BrideMobile - best 26.5
(2) 2005 Honday Accord- (1 -Corporate 1 - Personal) - 110,000 4-cyl 30mpg
2000 VW Golf GLS TDI, Upsolute Chip (sold to Brother, now 300+k on it) 48.5 mpg like clock work
1987 Honda CRX HF - Sold 87,000 always over 50 mpg Max 67 mpg

Whether it's yours or someone elses may not be meaningful!!!

Oh, let me clarify. The idea of oil testing has been thrown around a lot when discussing oil change intervals. My point is that you are trying to protect a $1500 investment. Who the f$% cares?

Now if you have a $50k engine, oil testing makes sense. And, why wouldn't you just change the oil if oil testing costs you $20? It just doesn't make any sense to me.

Therefore, I am doing a real life test with the method I recommend. Use synthetic diesel oil, change the filter once per year, top off as necessary.

That's it. Very simple. If one of the engines blows up, I was wrong. If nothing happens, I was correct. I don't want to complicate it any more than it has to be.

Yes, it's a sample of two. If others would like to join in, they are free to do what they will with their cars.

240Joe

rambow must work for the goverment or a university lets complicate a simple experiment
The state of NC after one of its hurricanes spent $1000000 to determine why there was so much flood damage After all was said and done they determined if so many people didnt live in the low lying areas there wouldnt have been as much damage Of course they used more and bigger words
I'd have told them that for $50000

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commercial fisherman diesel in my blood in my boats trucks and Dear old Dad has had me drivin them since i got my first license in 1968
1986 300 SDL 427654
1999 Chevy Crew Cab Dually 225423
1986 300 SDL 287000 Dad's
1987 190 Turbo 158000 Mom's (my inheritance)

Sooooo, your right till your wrong eh

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81 Mercedes 300SD 289k.......SOLD
82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project

Censored by the man

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine