Some of us are big fans of diesel engines. Huge fans even. We love the slow-revving grunt. We love the incredibly long time it takes them to run through a tank of fuel. We love lazily cruising at 70 mph while turning over less than 2,000 rpm. There's even more to love, but we have to admit, none of us currently own a vehicle powered by a modern diesel engine that requires AdBlue, a urea-based solution that breaks down nitrogen oxide in exhaust gases that's required for some diesel-powered vehicle to meet strict emissions standards. If we did, we might be a little irked like Tom Mutchler over at Consumer Reports.

Mutchler recently took the publication's diesel-powered Mercedes-Benz GL320 BluTec to a dealer because a warning light indicated that the SUV was low on AdBlue. The total bill for a refill? $316.99! The GL gulped 7.5 gallons of this costly solution, which accounted for $241.50 of the total bill. For those who don't do math, that's $32.20/gallon. Labor and tax accounted for the remainder, which is also shocking considering the only labor involved was twisting a cap and pouring.

It took CR about 16,566 miles to run low on AdBlue, which means they'll be spending $1,457.80 on the stuff over 100,000 miles. Sure, that may not be a lot of money for someone who just purchased a $67,000 SUV, but Mutchler makes a good point reminding us that BMW covers that cost for its diesel-powered vehicles up to 50,000 miles.

[Source: Consumer Reports]