I have owned several older BMWs. One of the most annoying features is the oil/service reminder light that uses a computer to tell you when to change the oil. Unfortunately it is powered by some rechargeable batteries that reside behind the dash that are a real PITA to change (and if you don't they will leak acid all over everything). So no computers in my benz, please.

The newer BMW's have a more updated service interval computer that runs on the cars electrical system. It uses many variables to calculate when you need to change your oil. It is a good system, however last time I changed the oil in the bmw it said I had 16,575 miles of driving to do before I need to change it again. Maybe so long because my wife does highway miles at low operating speeds. Of course I will be changing it at 5,000 miles regardless. Probably overkill. FWIW Porsche recommends oil changes at 15,000 miles with Mobil 1 for all of their new cars.

The best part of this system is that it guarantees people at least at minimum to change the oil every 15,000 miles or the car will void its warranty. So there is at least some basic protection regarding engine longevity. This is great for people like most of us that buy used cars with a lot of miles on them like my new to me MB diesel.

cheers

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'82 300d
'73 Alfa GTV
'86 Porsche 951
'00 BMW 323 sportwagen

Actually, by those that work on them everyday. It all depends on what you want out of you car. If you want it to last as long as possible then you'll drive it sensiblely and change the oil often. As for trusting the technology, Manufactors are not in the business of selling you a single car for life, especially GM. While I am a die-hard Chevy man, I know most of what they build today is junk (as are most cars). Dexcool is a joke as is the ability to drive up to a 100 miles with no coolant (claimed of the Northstar). Manufacturers have latched onto the idea of throw-away cars. They would rather sell/lease a new car to you every few years rather than have you hang onto it for 10 or more.

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85 300CD
83 300TD
78 240D (daughter)

Here are some of the best hour meters.
http://www.curtisinst.com/index.cfm?fuseaction=cProducts.dspProductCategory&catID=13

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ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

How about a 12V hobbs meter?
The planes I fly have them.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4517717497&category=26439

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85' 300D No inspection, No registration fees, Cheap insurance
"If my calculations are correct, when this baby hits 88 miles per hour, you're going to see some serious %$&^."

According to the lab I can go 6k-7k miles on my oil no problem, and that is still conservative. However oil is cheap I do it every 3k, if I had a newer gasser I would do it every 5k. This is with Mobil 1.

However a newer gasser with a large sump capacity could probably go 20k without a problem. Engines run cleaner these days, the computers control the fuel injection so well now that very few byproducts end up in the oil. Heck if they would put the right filters on these cars you would never need to change the oil.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Ever wonder why your city driver has black oil even with low miles? Now you know.

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Actually, my Diesels have black oil after they have been run five minutes. I have understood from reading numerous posts in this Forum and elsewhere that the reason is soot, a result of the oil-burning process.

The reason that oil for Diesels must be rated CF (Compression rating F) is that C-rated oil is designed to lubricate even when loaded with soot.

I change my oil and filter around every 5000 miles. The 90 has 166,000, the 85 has 194,000 now and neither seems to be down more than a quart after 5K miles.

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Semibodacious Transmogrifications a Specialty

1990 300D 2.5 Turbo sedan 171K (Rudolf)
1985 300D Turbo TD Wagon 219K (Remuda)

"Time flies like and arrow, yet fruit flies like a banana"
---Marx (Groucho)

Read your owner's manual. "severe driving" conditions require oil changes every 2500. Oil is cheap, engines are not.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member