It's my understanding the exhaust is filtered through a particulate filter (that traps, then incinerates exhaust particles), THEN the urea is injected to the nearly clean exhaust to convert the nitrous oxide into water and nitrogen. After 1,600 miles, my exhaust pipes are as clean as a whistle.

If this is true, then the urea injection, and also the particulate filter, shouldn't decrease the longevity of the engine. I'm guessing these X5s will go 500,000 with proper belts, hoses, fluids, etc. changed before anything becomes a problem. I can't discern any 'cheap' or 'flimsy' short cuts in the design or materials that would hamper longevity (my opinion).

My VW's have been an '00, '03, and my current is an '05. They are phenomenal if maintained and a relatively cheap.

I've known folks with Mercedes diesels with 500k+ miles with only proper maintenance (no major parts replaced).

I wouldn't worry about urea post-treatment having any affect on engine life, but the urea injection system may require maintenance at some point.

For most owners, while very interesting, this is all rather moot. The engine is not going to be the component that causes you to scrap a modern BMW, for 99% of us. It is going to be the nuisance failures of electrical components, or the complexity of the engine control software when updates are no longer being provided, or the expense of miscellaneous replacement parts that are specific to one model and long out of production by the factory.

A VW diesel going that distance is great, and I have no doubt that a BMW diesel or gasoline engine with similar maintenance could do similar distances. It is just that most of us won't find out.

If I was using non-OE filters (and I won't) I would definitely change the filter early. With original BMW filters, I don't worry about them for the standard interval. My vehicles are not in extreme service conditions; very dusty or other similar conditions would cause me to shorten up the intervals for both oil and filter. Having said all that, if I had very low annual mileage I would change oil and filter after 18-24 months, regardless of what the service lights said. My Z4 was on that schedule, as it was something of a garage queen.

Thanks JCL.

While I'm thinking about it.... One of the classic justifications for an early oil/filter change on new and rebuilt engines is to get any break in debris out of the engine ASAP, even it is has been caught by the oil filter. I'm not talking about microscopic trace elements found in an oil analysis, I'm talking about debris that would be visible to the naked eye, at least when concentrated by being collected on a magnet. My 60s era 911 and 70s era 530i have magnets in the oil pan drain plug. Even my '07 Kubota has a large magnet as part of the hydraulic oil filter.

Does anyone know if the current BMW engines, particularly the 35d engines, have any magnets to capture and hold onto metal fragments? And if so, where are they?

Funf Dreisig

Magnets are a lot less useful than they used to be, with all of the aluminum in modern engines. I have never seen visible metal fragments in my last five new BMW engines during oil changes.

> I'm talking about debris that would be visible to the naked eye

I can't imagine anything like that that getting through a modern engine oil filter, unless it was restricted enough to activate the bypass.

I missed this line. Hydraulic cylinders and their related circuits on heavy equipment (or, as we at work would refer to your Kubota, regardless of its size, on Lawn & Garden equipment), have little in common with engines. My experience is on similar and much larger yellow equipment from Peoria, but the principles are the same. The piston on a hydraulic cylinder is exposed to the natural environment when it is extended. When it is retracted, the seals wipe off the chrome rod. Remember that both sides of the piston are pressurized (for extend and retract). Eventually, the seals fail. When that happens, contamination ensures, and the equipment eventually starts making metal in the hydraulic circuit. That is what those magnets are for, to remove those large pieces before they take out the pump or control valves, or damage other cylinders that haven't yet failed. Not sure if your Kubota has pilot valves or not, but they are also a risk.

That's actually the point of the magnets in the drain plug. They catch heavier ferrous metal 'stuff' that rarely gets pulled into the oil flow and hence rarely gets to the filter. I'm saying 'rarely' because this 'stuff' can get sloshed around during spirited driving and then can enter the oil flow. Where they can get into the oil pump, which is before the oil filter.

Surely any mechanic who has changed the oil in a 60's, 70's, era VW, Prorsche, BMW has seen these magnets and hopefully cleaned off the metallic sludge that accumulates on them. They can be great diagnostic tools indicating increased wear or evidence of a damaged ring, etc. Note the cases of the VW and Porsche boxer engines of that era were made of non-ferrous metal alloys. AFAIK they may have even had a higher non-ferrous content (as a %) than the modern BMW engines. And even if not, most of the moving parts in most engines probably have a high enough ferrous content to be attracted by a magnet.

Maybe I'm just old school, having done all the maintenance on every vehicle I've ever owed (starting in the early 60's). EXCEPT that is for our 2001 X5 4.4i, which was was maintained by the book by BMW. BTW in 95,000mi that X5 required more repairs and consumed more oil than all the others combined. :yikes:

Maybe all the talk in this thread about high tech oils and low tolerance machining in modern engines is absolutely true -- MOST of the time. But stuff happens. And if it happens in my engine, I'd like to have a small magnet in the sump to capture any little ferrous buggers and hold onto them till the next oil change :)

Funf Dreisig

Hmmm..

The following image is of my then nearly new L3240 Kubota's Hydraulic filter when I did an early complete oil/filter and UDT/filter change after only 50 HOURS of service.

FWIW the Kubota just ticked over 400 hours and I will be doing the full maint. including replacing the 11 GAL of UDT this week or next.

Funf Dreisig

p.s. Kubota recommends replacing this filter at 50 hrs but not the UDT. While this is possible, this filter is a horizontal screw on with 11 gal in the sump. So replacing it without losing quite a bit of UDT anyway, requires fast hands and some skill/luck :)

Many of you have forgotten more about modern engines, than I ever knew,
but my 3 m'cycles have a magnetic drain plug, our '03 CR-V has one, etc.

I don't see the CR-V plug often, but I do see the GoldWing, 'Cane 1000K and
my ol' HD drain plug(s) at least twice per year and even after all this time/miles
there is and, always have been a slight "fur" of metal on the plugs. No, I don't
do oil analysis, and the youngest scoot is a '94, and they all run better than
my Rolex.

No dog in the discussion and it isn't exactly germane, but I would think a
mag. drain plug can't hurt anything, even in these "finely constructed" BMW
engines.

Great Thread, imo...
GL,mD