Back in the early-2000's, BMW was claiming 20k-mile oil change intervals (OCI's) were sufficient. That didn't end well. Now, they're at 10k miles. My 2002 M3 calculated OCI's based on the fuel burned: When X liters of fuel has been burned, it's time for an oil change. My M3 wanted an oil change at around 13k to 13.5k miles. I did mine at 6.5k miles. I'd get every other one for free with BMW's free maintenance.

I've done 8k-mile OCI's with synthetic oil on a V6 Honda, a Chevy Cobalt, and now two turbocharged BMW's. Looking down the oil fill holes, the engines are spotless. The plastic timing chain guides turn from white to brown, but that's the plastic absorbing oil, not the oil leaving deposits. This will cost me about $300 (three oil changes) more than 10k-mile oil changes over 100k mile. But, I know the engine will be clean.

Varnish (brown coating) on the valve cover and stationary parts visible down the oil fill hole doesn't really hurt. But, if there's varnish there, you have to worry about what's lurking on the pistons and piston rings.

About 55% of new BMW's (and M-B's) put on the road in the US are leased, usually for three years. I suspect most of those lessees never open the hood. If they get a low-oil or low-coolant warning message, they take the car in for free maintenance.

There was a woman on a BMW board who had her leased BMW towed into the dealership because she got a low-coolant warning. It never occurred to her to open the hood and add some water to the coolant tank. A lot of BMW lessees bring their car to the dealership when they get a low tire pressure message, too.

BMW's now have two coolant circuits, one for the engine, one for the intercooler and turbocharger.

Synthetic oils are a wonderful thing indeed .

I'll still be doing my regular hot oil and filter changes until I die .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Doesn't seem to be a good model to own:

https://www.carcomplaints.com/BMW/550/2013/engine/engine.shtml

https://repairpal.com/cars/bmw/550i/2013

Too many failures

That is probably why you can purchase a BMW reman unit for $4500.

__________________
Jim

Bavarian

Money

Waster

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Those V8's are junk, my friend has one in an X5 that needed to be replaced. I wouldn't own one past the warranty.

I see them blowing blue smoke all the time.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

They run so hot that they dry out the rubber valve stem seals.

Yabbutt ;

Running and engine at or slightly over the boiling point if the engine's properly designed (and maintained) makes it last longer, get better fuel economy and boosts power .

Sadly to few ever think about the cooling system until it blows .

It sounds like this is just one more poorly designed BMW automobile : great for five years maximum then all bets are off .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

The four-cylinder and six-cylinder engines are fine for the most part.

The N55 six-cylinder engines develop a leak in the oil filter housing gasket after about 70k miles. Same with the valve cover gasket, which is a non-planar, piece.

It's important to change the belts and tensioner in timely manner. If not, the belts can come off, ball behind the pully, and... wait for it... get pinched by the rotating pully shaft and sucked into the engine up the shaft hole.

The four-cylinder N20/N26 engines, 2014 or earlier had bad timing chains and guides. They fixed that with 2015 production and gave an extended warranty (7 years/70k miles0 on pre-2015's. It'd cost about $4k to have the bad engines upgraded.

BMW's generally get better fuel economy than the corresponding M-B's. BMW beat M-B to market with fuel effiicent turbocharged engines.

About 55% of new BMW's and M-B's put on the road in the US are leased. Most people who drive them probalby never open the hood for the three years they have them.

Uh oh, one of turbos is hard to turn. More stuff to fix. Will attempt to blow out all the oil lines.

__________________
Jim

Sounds like a good way to go. Ideally it will be cheaper for her than buying a used one of similar value. Thanks for the update, I remember this thread.

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1986 300SDL, 362K
1984 300D, 138K

The I6' seem decent, my business partner just picked up a 2022 Z4 M something or other and it rips.

Like all late model German cars I wouldn't own one outside of the bumper to bumper warranty period.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

I knew someone who was in on the development of Mobil 1. This was the first full synthetic to be mass marketed. In initial testing they ran cars for 250,000 miles around test track. An engine tear down showed no wear.

So they advertised you could run it for 15,000 miles between oil changes.

Eventually they backed off that claim. Further testing showed that if you are running a car steady, day and night, for 250,000 miles the wear is minimal with full synthetic. But stop and go traffic? Not so good for the engine with 15,000 mile intervals.

A classmate of mine in engineering school was a technician at GM's engine test facility. One of their tests was running an engine continuously until it failed. (I guess they fed fresh oil into it at some point.) He said that under those conditions, the aluminum block Chevy Vega engine was the record holder. He said that all that engine's trouble happened at start-up.

I read about synthetic oil in the April 1976 issue of Popular Science.

https://books.google.com/books?id=FAEAAAAAMBAJ&printsec=frontcover&hl=en#v=onepage&q&f=false

I talked to a manager at a Ryder maintenance shop back in 1977. The home office told him to put synthetic gear oil in some new trucks leased by customers who really racked up miles fast. Later, they sent him new transmissions and axles for those trucks and told him to swap them out and send the lubricated parts back. When he first looked at the parts, he panicked, thinking the mechanics had taken apart new trucks by accident. (He said they didn't use synthetic oil in engines because the filtering wasn't good enough at the time.)

In 1976, my mom's car's engine was all sludged up. My car's engine was burning and leaking oil. So, neither were candidates for synthetic oil. My mom got a new car in 1985. After about 1500 miles (break in), I started using Mobil 1 5W-30 in it. It'd use a quart of oil about every 2300 miles. That was good for a Ford of that era. I worked as a courier for a bank in college. They had a fleet of Ford 3.8 V6's, and they'd use a quart of conventional oil every 2000 miles.

I go see my mother Sunday mornings. Part of that routine was checking the fluid levels in her car. After about 10k miles, the car started using a quart of oil about every 2800 miles. It took 10k miles for the rings to seat. I got the car after 70k miles. At about 100k miles, the fuel injection was acting up. The first dealer couldn't fix it, but the second one did. When I picked up the car, the service writer had taken the car for a check drive. He asked me it the car had a new engine. He said he'd never seen a "302" (a whopping 140 h.p.) with that many miles run that good.

I eventually got tired of giving my "synthetic oil speech." Mechanical engineers would get it, but electrical engineers usually didn't.

One of my MSEE friends bought a used Oldsmobile from an elderly neighbor back in the early 1990's. It'd had regular oil changes, but eventually failed due to sludge. He had connections at a GM dealership and got a new engine for $1500 and put it in himself. It took him and a friend about 40 man-hours. I gave him the synthetic oil speech." He listened, but came back Monday morning saying "I went to Wal-Mart over the weekend and looked at that Mobil 1. Even doing an oil change myself, it'd cost $40." I reminded him that his last oil change cost $1500 and took 40 hours to do.

I finally made an Excel spreadsheet. It took all the variables associated with the cost of an oil change, the cost of gas, MPG, and the expected improvement in MPG using synthetic oil (a conservative estimate today is 2%). It'd then calculate the break-even oil change interval (OCI), usually only a few more miles than a typical conventional oil's OCI. It'd then calculate the cost savings from an extended OCI using synthetic oil. Later, I added a projected cost savings over 100k miles. If you accounted for the value of your time doing or getting an oil change, the savings were huge. It'd be on the order of $1000 over 100k miles.

When I was working at the bank, I tried to convince them to use synthetic oil. They drove about 1M miles per year in our operation center, and the bank had three other operation centers. They probably racked up 5M miles/year on bank owned vehicles. They wouldn't listen. They also weren't interested in my suggestion to check the air pressure in the tires regularly.

Years later, I was back in the city where I grew up and went to college. I was on the interstate, about two miles from downtown, where the bank's operation center was. I saw a bank courier car parked on the shoulder. I recognized the "NO CASH CARRIED IN THIS VEHICLE" sign in a back window.

About a mile down the road, I saw one of the guys I'd worked with walking along the shoulder toward the car, carrying a gas can. If they'd used synthetic oil and kept the tire pressures up, he would have had enough gas to get back to the operations center (which had a gas pump). That made my day.

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The only thing more expensive than the maintenance cost of a luxury German car out of warranty is the depreciation cost of a luxury German car still under warranty.

About 55% of new M-B's and BMW's put on the road in the US are leased. Driving 12k miles/year, the cost break-even point between leasing and owning a BMW or M-B is about six years. That about the average of how long a new-car buyer keeps their car. The manufacturers subsidize leases with inflated residual values. They make that back by stimulating demand for their new cars. It also keeps their dealerships stocked with three-year old used cars.

I keep accurate records of my cars' costs. I look up the KBB values on the anniversaries of their purchases and at the end of the calendar year. Based on accurate cost data, I keep my cars an average of almost ten years and over 100k miles. I had a BMW become a money pit after 100k miles, with the annual total cost being higher that the average annual total cost since new. The car was also not "road trip reliable" anymore. So, from now on my BMW's, or maybe an M-B someday, will go away around 100k miles.