The manual for my '92 190E 2.3 says that it should be changed every 7500 miles. Everyone I've talked to says that oil should be changed every 3000 miles. Is it OK to go 7500 miles between oil changes?

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That 7500 mile interval is probably for ideal driving conditions. Chances are your 190E manual advises a more frequent interval for severe service. I don't follow the 'universal' 3000 mile recommendation. I tend to go more by the type of car and driving I do. For my daily driver '84 Accord I try for between 4000 and 5000 miles - closer to 4000 with mostly city driving or around 5000 with mostly highway use.

On the other hand, my 44 year old Fintail gets little highway driving and her ancient Solex carburetors tend to run rich, especially when using the manual chokes in cooler weather, so I've been changing that oil about every 1500 miles.

The best thing I've found to try and keep to some kind of schedule, is to put a sticker up on the windshield to remind me of the date and miles of my LAST oil change.

Happy Motoring, Mark

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DrDKW

To remember, I try to change on the solstices and the equinoxes: March 21, June 21, September 21, December 21. Change of seasons; easy to recall. Once I've finished a change, I write the cost and the mileage down in my expenses book.

Most of my driving is done in the city, with a moderate amount of highway travel, so (especially in colder weather) I make sure I change it every 3 months. Which, driving here, works out to about 2500-2700 miles.

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-- Paul W. (The Benzadmiral)
('03 Buick Park Avenue, charcoal/cream)
Formerly:
'97 C230, smoke silver/parchment; '86 420SEL, anthracite/light grey; '84 280CE (W123), dark blue/palomino

Oil is so cheap (dino oil) and with an engine with 230,000 miles I change mine if I don't like the color of it never mind 3,000 miles. Go with you gut instinct. I changed my oil 18 times in two years (I drive a lot). Try keeping a small notebook as a DIY service record - works for me.

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dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles

Definitely keep a logbook for each car to document maintenance and repair. There's no need to guess when maintenance was done. It also helps to have this logbook available when you decide to sell the car.

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95 E320 Cabriolet, 159K