Consumer Reports discovered this firsthand when it brought a Mercedes-Benz GL350 diesel SUV to the dealer to fill up on AdBlue, the urea-based additive that keeps large turbo-diesel engines emissions-compliant by breaking down smog-producing nitrogen oxide into water and nitrogen, and the vehicle will stop running if the fluid runs low.
After a year of driving and with 16,565 miles on the odometer, the GL350 required a top-off of AdBlue to the tune of $32.20 per gallon for 7.5 gallons. After labor, the bill came to a hefty $316.99.
According to Consumer Reports' calculations, at this rate AdBlue costs alone would total $1,457.80 (without labor) for 100,000 miles of driving, canceling out roughly a third of the fuel savings you get instead of buying a comparable vehicle such as the GL450 V-8. (There is no gas-powered V-6 GL.)
Like we said, though, it’s all about balance. A simple oil change at a Mercedes-Benz dealership will set you back $100 every year, according to the folks at the service center of Mercedes-Benz of Chicago. In other words, if you’re buying a luxury SUV somewhere in the range of $67,000, you probably shouldn’t be shocked by most service bills.
Then again, if you buy a BMW diesel, the free maintenance plan makes AdBlue free for the first 50,000 miles.