super7pilot

When one has been driving any engine with a turbo charger and you pull off the road or come to a quick stop after having been on the gas. You should let the engine idle for a minute to let the turbo(s) slow down & cool down. If you simply shut the engine down while the turbos are hot and are still spinning can lead to bearing oil starvation.
Of course with the modern synthetic oils & turbos it's not as big an issue as when using conventional oils and spigot bearing turbos. Conventional oils can coke up when over heated. So cooling down then shutting down is not a bad habit to have. And of course it's not a good habit to start a cold engine then jet off under full boost. It's not an issue getting underway when the engine is cold. Just don't hammer it. And while a modern diesel can rev a bit. It's really not necessary. With max torque at 1600-2800 RPM there's no real reason to be above 3000 RPM. The slower an engine can spin and still get work done (torque) is the secret to a turbo diesel's longevity. So if you drive your diesel like it's a diesel and not like it's an AMG gas hotrod engine. You will have the best chance of it having a very long life.

super7pilot

Having lived in Germany for the last 4 years. I just can't believe the range of cars that one can get with a diesel engine. Nor the lack of the same in America.
I my self ended up with the Merc only because there really was no alternative for having a vehicle that can tow my Caterham and still return good economy when not towing.

I was actually looking at a Jetta TDI. Over here in Europe a VW TDI can haul 3300Lbs, In America the same TDI from the same factory that makes the EU version can only tow 1000LBS. Upon calling VW USA to inquirer about the discrepancy. VW USA told me over the phone that American's expect a tow vehicle to be big and so they will only authorize their bigger and more expensive SUV's to tow any load. MB was the ONLY manufacturer to offer an SUV with any mind towards towing & economy. BMW has seen the light and are going to offer an X3 with the two litre diesel in 2015. VW wants to release a Tiguan with the TDI engine in America, But is not sure it can make enough engines to meet demands.

But there is still the stigma of most American's thinking that a 4 cylinder engine is not capable of doing any thing. And certainly think that it has no business towing a load. And 4 cylinder engines are only put in cheap econo box cars. Of course the American's don't have to pay almost $10 per gallon for fuel like Europe does.

Rascally Wabbit

As to super7pilot's comments, a couple of things come to mind. The majority of car sales in Europe are diesel powered where driving distance is likely even shorter than what we do in the USA & there are no issues that I know of. The reason for their diesel choice is simply cost of fuel. As to shut down procedure, I surmise this is in reference to turbo spool down period which applies to gas as well as diesel applications. Modern design of coolant systems & turbochargers along with better quality lubricants (true synthetics i.e. Mobil 1) have taken care of most of the issues. Yes, I do allow my car, turbo or normally aspirated to run for a few minutes when exiting the highway for a break, likely due to the habit from the day when turbo equipped cars did need those few minutes. But I doubt if it is mentioned or recommended in the GLK 250 owners manual.

super7pilot

Mr. Wabbit.
Even though diesels are a large part of all auto sales in Germany & the larger part of the EU. The main issue with diesels here in Germany is that in the pure inner city stop & go they aren't as economical as gas. Most of this comes down to the fact that German's at all times drive like their hair is on fire. Which is not the forte of the diesel engine. Even though the diesel fuel is slightly cheaper. The road tax is higher on diesel autos. Of course the buss & train system is about 100 years ahead of the USA. And that's the key. A large number of folks leave the car at home and use public transport to commute to work. So a lot of folks mostly use their diesels or cars in general for the long distance family holiday & shopping trips more than popping down to the 7-11 for a slurpy or in town commuting to work.

I would also say that just because the manual doesn't mention letting your engine cool down a bit before shutting down. Doesn't mean you shouldn't.

I would harken back to the days of the 3000 mile oil change. It seemed that suddenly all the makers were saying 7500 miles was ok. (this mileage change predates synthetic oils) Turns out the main reason for that change was the fact that the auto makers saw that most customers were not sticking to the 3000 mile recommendation and were doing on average 7500 miles between changes. so they made that the standard. It didn't do the engines any good. But by the time the customer realized the engines were wearing faster from dirty oil it was to late as the warranty had already expired. So the auto makers had nothing to loose by extending the intervals. The BMW 328 we sold when we bought the GLK had an oil change interval of 15k. We changed it every 5000 miles. We will stick to oil changes at 5k on the GLK as well. Oil is cheaper than a rebuild. And a minute of cool down is free. But remember the old Pennzoil commercials? As the mechanic was changing the oil he said "you can pay me now (for the oil) or you can pay me later(for the new engine)" Brilliant commercial.