E39 530i Service Intervals - Maximum safe interval?

The service intervals are much more complex than that - the ECU monitors the condition of the oil as part of it's decision making. A 530i will have been a director's company car, no doubt, which means it'll have spend a lot of time cruising up and down motorways where oil will remain in good condition for many miles. I wouldn't worry about it myself.

The UK service book has a diagram of the service lights which should be marked at each service so you can see it was done on time or not.

If the car is running perfectly at 140000 miles I'd say it's been properly serviced?

"SteveH" wrote

Does it really? I thought it just counts the number of engine starts and gallons/liters of fuel consumed, maybe also the rpms. I was not aware that it somehow monitors the oil condition. Do you have a link to some more literature of how this actually works?

Thanks, Pete

Just what I'd been told [1] about variable service intervals. Something to do with measuring translucency.

[1] By a salesman.

"SteveH" wrote

The reason why I find it suspicious is that even if you change your oil, but do not physically reset the oil monitor, it'll come on telling you to change oil. If it was able to monitor the oil condition, it would know that the oil is fresh and would not come on. At least that's how it is on the US-spec BMWs.

Ah, that explains a lot. :)

Cheers,

Pete

When SI first were installed in BMWs, the computer measured several parameters to determine when service was due. They included things such as # of cold starts, # of warm atarts, mileage, engine operating temperature, and perhaps others.

BMW found that all these complicated calculations equated to the number of gallons of fuel burned. So now, in the latest models, the only thing that determines service intervals is the amount of fuel the engine has used.

There is no optical sensor, no "analytical chemist in the oil pan", no particulate sensor, no nothing. When you have burned "X" amount of fuel, you are due a service.

Not only that, but freshly changed oil goes black very quickly from the small amount of black stuff left in.

Indeed.

Of course, /European/-spec BMWs have a built-in gas chromatograph-coupled mass spectrometer to check the oil composition ;-)

Andrew

"Bob Smitter" wrote

That's what I thought.

Is there a way to adjust the "X" amount (with service tool/computer)? I was thinking that "X" could be different depending on the type of oil you use, ie. smaller for mineral oil, larger for some "long life" type oil (available in Europe).

Thanks, Pete

"Andrew Morton" wrote

Well yeah. If anyone out there came up with an oil sensor that judges oil condition solely by its color, then it's a very poor sensor. :) I can do that myself by pulling the dipstick (sans the newest BMW models), alas it's pretty useless as you mentioned.

I think GM/Delphi developed some kind of an engine oil sensor that monitors oil condition (and not by its looks), but I can't remember now what it measures exactly and onn which cars it is used.

Pete

SteveH wrote:

OK, found this from way back in 1997:

Capacitive sensor measures oil quality A unique oil-quality sensor under evaluation by Cummins, Detroit Diesel, and BMW, may someday signal drivers when their oil needs changing. It's based on a low-cost ceramic capacitive sensor that measures variations in the dielectric constant of the oil. New motor oil has a dielectric constant of about 2.19, but after about 400 hours use, the antioxidant additives in the oil break down and the value climbs to roughly 3.20. The sensor works much like any capacitive sensor. The substance to be measured (oil) passes freely between two small, parallel metal plates spaced roughly 0.010 to 0.020 inches apart. With the area and spacing known, the capacitance value becomes a function only of two values: the dielectric constant of the oil itself, and one major stumbling block--temperature. "Nobody knew how to block off the temperature effect and only measure the aging of the oil," says Kyong M. Park, vice president of R&D at Kavlico (Moorpark, CA), the sensor's manufacturer. His patented solution: incorporate an analog signal conditioner consisting of feedback resistors for offsets and gain, and select one resistor that changes resistance in direct proportion to oil's dielectric-constant variation with temperature. Park also overcame a soot contamination problem present in diesel engines. "We developed a special silicon-based coating to prevent the soot from sticking to the sensor," he explains. A serendipitous advantage of the Kavlico sensor is that water contamination-a fairly common and damaging situation-can also be detected because the dielectric constant of water is 87. "A one-percent contamination of the oil with water or coolant will increase the dielectric constant enough to trigger an alarm," says Park. Kavlico isn't the only company working on an oil-quality sensor. Control Devices (Standish, ME) has joined forces with the University of Maine to produce one; Sandia National Laboratory has a sensor in development; and SRI International (Menlo Park, CA) has produced a laboratory prototype for a auto-manufacturer customer. Park isn't worried. "{Other methods} measure the oil's acidity, which is less reliable," he says. Surprisingly, the capacitive concept isn't new. "I remember reading a Popular Science article 30 years ago about this," says Park. "But nobody ever made a production sensor before that could do it."

This was published years ago, and BMW advertise cars as having an 'oil quality sensor' - so it looks like they've been fitting them for a while (Certainly since the fugly 5-series was launched). Might not be in the specs. of an E39, though.

There's always somebody who is not happy with his lot, however good it is. Thinks there's something wrong when there isn't...

These automotive forums are a good place for this, especially in worrying about oil-change intervals. "I have run my 2004 premium brand car for 7 000 miles since last service and the service indicator hasn't come up yet. Should I have changed oil at 3 000 miles...?...Will my engine blow up at my next drive?..."

DAS

For direct contact replace nospam with schmetterling

Obviously a great one, because he made it up and yet you beleived him. It does no such thing. It does all the calculations based on running time, number of starts, etc. No magic oil sensors...

Actually - the later models do it strictly on fuel consumed.. which if you think about it takes into account cold starts (more fuel), short drives (more fuel), hard use (more fuel)..

So many liter of fuel used (depending on engine) and the light turns on.

Read the link I posted and the spec. sheet for a new BMW, then.

(I was looking at 3-series until I found out how much BMW want for a half decent one)

OK, it's not based on translucency - but BMW *do* fit 'oil quality sensors' these days.

There certainly is if you have a VW...

Chris

I read that Merc were one of the first, so I'm not surprised BMW now do.

I'm not certain that it can actually monitor oil samples, but I have every confidence that if the computer knows the car starts, runs for an hour at

70, then another 40 minutes ar various speeds, then stops. then starts again, runs 40 minutes at various speeds, then goes an hour at 70, then stops, it should be able to compute that the oil -- assuming the oil meets the specifications -- should last for a defined period. Your and my performance might be different than the OP's, but our driving pattern should be significanltly different as well.

Oil is a very precise science, and the old days of changing the oil because

90 days, or "x" thousand miles, have gone by is just not valid anymore. We need car makers to monitor this sort of stuff, and turn on a light, as BMW does, that alerts us that we need to change the oil. Oil is in increasingly short supply, and changing it before it is needed -- time or miles have passed by -- is simply unacceptable these days.

It has been a long time since the 3000 mile oil change was a real requirement for the health of your engine. Today, most cars go 7500 miles according to factory warranty specifications, and some cars go much longer. I'm surprised the Sierra Club, et al, do not go after Jiffy Lube, et al, for prompting us to change oil when it isn't necessary.

That actually makes lots of sense. And, it's simple.

No it doesn't. The E39 system monitors fuel burned only. Its a pretty good approximation of the service the engine has seen (highway miles - better mileage - oil lasts longer and vice versa). Supposedly, the E60 is more advanced.

R / John

Service intervals for a 530i in normal operation (mix of driving conditions) will be in the 15-16000 mile range between oil services. The service interval is Oil/Insp1/Oil/Insp2 etc. Your major inspections occur at approximately 32000 mile intervals (they include an oil service).