On a lighter note, the original owner of my '79 300SD had the oil changed, by the same shop, once a year. She was a widow who commuted to Florida from the Minnesota border. (She didn't pop for the cassette or the passenger mirror-let's say she was frugal), She put 100,000 miles on the car in 4 years. So we have 25,000 miles between oil changes.
The second owners tortured the car, by having it painted at Maaco (It's now a redhead, with an ivory body). They changed the oil even less frequently. The car has the original timing chain, and no replacements of any engine components whatsoever. Just a new tach cable. The rocker panels have absorbed all the pain.
I change the oil twice a year because of the change in weather temperature. It is about every 2000 miles. The car has 340,000 miles and goes like a "bat out of hell" (Meatloaf).
The only explanation for my luck, is that the engine was made by Mercedes.
I think this story is comparable to not flossing your teeth regularly. You may skip it, and later live to regret it, or you just might get lucky, and have teeth made by Mercedes. But why take the chance of gumming it through eternity.
(I said lighter note)
I am a huge Toyota fan. I just sold a 1988 Land Cruiser with 200,000 miles on it. I completely restored the body due to typical Toyota rust. The engine will die in 10-20,000 miles. I know this, the buyers all knew this. It's a sad truth made uglier by the Mercedes automobile. It was not easy to sell a truck that was over 200,000. Only a real Toyota devotee would not have a problem with the high mileage. on the other hand, my 300 SD is only going to get better every year. I will wear my high mileage badges with honor, and if we ever part, mileage will not be an issue. I would buy a Mercedes with 600,000 miles on it and not think twice.
I will stick with Mercedes for the rest of my life.
Toyota, Mercedes, and many other foreign car makers have always made a "200,000 mile" engine. Ford and other American car companies have always made a "100,000 mile" engine. Just in the last few years, Ford has started making a "150,000 mile" engine to attempt to compete with Toyota trucks. It is pretty obvious that Mercedes was using 200,000 for a minimum.
Mercedes prides itself in making parts available for all years, and models. I can get any part for my car. Last summer I ordered the inner frame rail(with jack ports) from the dealer for $80.00!!! To me that is remarkable. I never was able to purchase anything for my '88 Toyota at the dealer, in fact, the parts people basically told me that my '88 was obsolete. Parts were "rare", and very expensive. They want you to buy a new car. They claim their parts are 3 times stronger than other auto makers,Thus the outrageous prices. The customers service records are kept up in an attic after the car is ten years old because they assume it is dead. I will always remain a fan of Toyota, but they are miles behind Mercedes as far as what's important to me.
Mercedes sold more cars in the U.S. last year than at any other time (205,614). Lexus beat Mercedes this year by selling 423 more cars to become the number one seller in the luxury market.
Donald, my mother has owned more 10 year old Cadillac's than I can remember. I have always been impressed by the Cadillac engine. I drove a '73 Sedan DeVille to high school every day with a broken fuel gauge. That car was my pal, because every day I ran out of gas no matter how much I put in. She was thirsty, and I hated high school. The only complaint I have about Cadillac is the early '80's Eldorado that was supposed to be fuel efficient because it shut down from 8 to 4 cylinders when the extra power wasn't needed. I hope you did not design or have anything to do with that. If so, my apologies. I mean it in good fun. I have driven through the Mew Mexican desert in a Cadillac, and it was dreamy. I can only imagine how nice it will be in my Mercedes.
DISCLAIMER: I DO NOT CONDONE OR ADVISE NOT CHANGING YOUR OIL, UNLESS YOU JUST PLAIN FORGET.