New Diesels to come: high diesel fuel costs

[Boston X5 4.4]

Originally Posted by gresch

Diesels have the same break/fix issues as the gas versions, as it's usually the electronics and non-drive-train parts that break on BMW's.

WHAT?
The diesels won't come with better window regulators and cv boots?

[DSE]

Originally Posted by KEF

I'm curious, on what do you base your opinion on the reliability of the diesel vs. V8?

Thanks,
KEF

BMW's V8s have had a history of teething problems, and while I think BMW has resolved the most serious issues, the V8s still require more maintainance and repairs.

As a general rule, diesels are chosen for large commerical applications because of their torque in pulling heavy loads and longevity. It is not uncommon for diesel trucks and tractors to have over a million miles, while gasoline engines are assumed to have a maximum life of a third or less than that. Likewise, it is not unusual to see diesel Mercedes 300Ds in the states with over 400,000 or 500,00 miles on the engine.

[KEF]

Originally Posted by DSE

BMW's V8s have had a history of teething problems, and while I think BMW has resolved the most serious issues, the V8s still require more maintainance and repairs.

Thanks, I was not aware of previous issues - but regardless I don't anticipate that the new V8 motor in the 4.8i should present any issues; but that is simply based on opinion and nothing more.

With respect to longevity of the diesel motor, the reality is I no longer expect the life of the motor to be the limiting factor for ownership, but what you say is true.

Take our new X5 as an example – what scares me, it the amount of tech-wizardry that is inside this vehicle. Sure, under warranty any gremlins will be duly corrected – but think about the number of sensor, detectors, etc inside this car.

I can not phantom at this point what the cost of ownership could potentially be out of warranty.

After 4yrs / 50K you are rolling the dice – and the price could be steep once electrical issues start to creep in with old age.

I believe that the days of 10-15 years of ownership are more than likely over – let alone putting 400,000 miles on one of these things, be it gas or diesel.

Best Regards,
KEF

[DSE]

I agree with your observations, and was focusing on longevity and reliability of the engine itself.

Unlike most folks, I buy a car outright and hold onto it a long time. I maintain it religiously. I drove my previous car -- a Toyota -- for 19 years. While I certainly don't intend to repeat that again, my 2001 BMW 330i still looks and drives great, and post-warranty repairs and maintenance have all been reasonable so far (knock on wood), so I am keeping it for awhile (I thought the new 5 series would tempt me, but I just don't like the styling).

But I agree with your point about the electronics and gagets. That is the limiting factor. On my Toyota, the car still ran great, it was the wear and tear on the interior that wasn't worth fixing.

[KEF]

Originally Posted by DSE

I agree with your observations, and was focusing on longevity and reliability of the engine itself.

But I agree with your point about the electronics and gagets. That is the limiting factor. On my Toyota, the car still ran great, it was the wear and tear on the interior that wasn't worth fixing.

Yes, I appreciate your point of view - I am not aware of any issues with the current V8 in our vehicle.

I would love to be able to keep a nice vehicle long term, but these days I am not sure how practical it really is. Sad in a way, but the days of wrenching on your ride are long gone.

Shift gears? Press a button. Park? Press a button. E-brake? Press a button. Move the seat? Press a button. Open the boot? Press a button. And on and on...

All of this tech costs big money, and that price will become all the more apparent in about 5-6 years once we have to keep all of these SAVs on the road.

Cheers,
KEF

[JCL]

Originally Posted by DSE

As a general rule, diesels are chosen for large commerical applications because of their torque in pulling heavy loads and longevity. It is not uncommon for diesel trucks and tractors to have over a million miles, while gasoline engines are assumed to have a maximum life of a third or less than that. Likewise, it is not unusual to see diesel Mercedes 300Ds in the states with over 400,000 or 500,00 miles on the engine.

Cool, an engine discussion

Commercial diesels are chosen for their torque rise characteristics. Individual engines are designed for longevity, but that isn't a function of them being diesel, it is a function of the design brief. Other things being equal, longevity will be related to maximum piston speed (a function of stroke) and peak cylinder pressure. Diesels have much higher peak cylinder pressures than gasoline engines, so you get fatigue in the block and engine components, as well as that characteristic rattle. Piston speed is addressed by slowing down those heavy engines; a 14 litre highway truck engine will be shifted at 1200-1300 rpm. Fatigue is addressed by building them heavy.

Neither of the above applies to a higher speed, aluminum block, BMW automotive diesel. Conversely, Mercedes diesels in the 300d were heavy, and had a lower specific output.

There are direct comparisons. Medium and large industrial diesels from several manufacturers are available in natural gas versions (spark ignited) for gas compression stations, generator sets, and other industrial applications. Same block as the diesel version, same piston speed, with a cleaner burning fuel, and much lower cylinder pressures. Demonstrated longer engine life.

All that said, while the diesel can be expected to wear out sooner, I agree with the poster above that it is somewhat academic. We don't keep cars until their engines wear out, and the electrical sensors and accessories are far more likely to be the reason the vehicle is eventually scrapped.

Still, since the M in BMW stands for Motor, it is good to see an engine discussion on the board.

[Quicksilver]

So are MBZ diesels aluminum block??

And is the fact that BMW diesels are aluminum a factor resulting in a quicker wear out rate?

[rh71]

Originally Posted by KEF

I can not phantom at this point what the cost of ownership could potentially be out of warranty.

After 4yrs / 50K you are rolling the dice – and the price could be steep once electrical issues start to creep in with old age.

I believe that the days of 10-15 years of ownership are more than likely over – let alone putting 400,000 miles on one of these things, be it gas or diesel.

Best Regards,
KEF

Extended warranty from Warrantydirect.com may be a smart choice - I will be considering it depending how my first 4 years go.

[JCL]

Originally Posted by Quicksilver

So are MBZ diesels aluminum block??

And is the fact that BMW diesels are aluminum a factor resulting in a quicker wear out rate?

The 300d quoted above was a lump of iron, with indirect injection, naturally aspirated, that started out at 80 hp. That is the type of heavy, overbuilt, understressed design that quite comfortably went hundreds of thousands of miles, often in taxi service. That reputation was well-deserved, but has nothing to do with a modern higher-speed higher-output diesel.

The E320 CDI I6 (2006) was cast iron. The latest E320 Bluetec V6 is aluminum. BMW diesels have been iron up until the latest generation.

My point is that the reputation enjoyed by older automotive diesel engines can not be applied to the latest generation of automotive diesels. When comparing gasoline and diesel engines of similar output, and similar displacement, the diesel is stressed more, it is a simple design fact. That is not to say that it will wear out prematurely, but it should not be expected to outlast a similar gasoline engine.

A lot of the early adopters of Volkswagen Rabbit diesels (many of whom switched over from the Mercedes 240d) learned that years ago.

[KEF]

Originally Posted by rh71

Extended warranty from Warrantydirect.com may be a smart choice - I will be considering it depending how my first 4 years go.

I am sure that this woudl help defray some of the cost, but based on the price of sensors / fixes for the E46 M3 I had and what others reported, I made the decision before I bought this car that after 5 years of ownership it had to go.

KEF