Slowly – finally – diesel engines are becoming available in the kinds of vehicles that really could use ’em : crossover SUVs.
These vehicles are bought because they’re roomy, versatile and useful. But their design layout also inclines them toward being large and heavy and less than aerodynamically efficient.
Which, in turns, tends to make them pretty thirsty.
Diesel engines address this deficit.
Some current gen. diesels are also great performers. This ’14 Audi Q5, for instance. It can haul itself to 60 in the mid-sixxes.
And it still delivers more than 30 MPG on the highway.
Which is like having six pack abs . . . even though you drink a six pack every day.
WHAT IT IS
The Q5 is a compact crossover SUV. It seats five in two rows and like its premium class rivals – the Mercedes-Benz GLK and the BMW X3 – offers diesel power and (with the diesel engine) standard all-wheel-drive.
Unlike its two chief rivals, however, the Audi’s diesel is a six-cylinder diesel.
Both the X3 and GLK diesels are four-cylinder diesels. Â Â Â Â
Base price is $46,500 – vs. $42,825 for the X3 diesel and $39,905 for the Benz GLK diesel.
WHAT’S NEW
The Q5 is a carryover (from 2013) but it’s now available with Audi’s extremely impressive 3.0 liter TDI diesel V-6 engine. Interestingly – happily – this engine, which is also found in the Q5’s big brother, the three-row/full-size Q7, produces more power (well, more torque) in the smaller/lighter Q5.
WHAT’S GOOD
Class-leading acceleration, while delivering fuel economy numbers almost as good as its four-cylinder (and not nearly as quick) competition.
Rich feeling, handsome-looking cabin.
Roomier than rivals – especially in the second row (and behind the second row).
Hearty towing capability (4,400 lbs.)
WHAT’S NOT SO GOOD
Big price difference between it and the Benz GLK and X3 erases much of the Audi’s efficiency advantage.
Overdone MMI interface.
Diesel fuel fill sometimes doesn’t match diesel nozzles at the fill-up joint, making for slow (and messy) fill-ups.
UNDER THE HOOD
The Q5 diesel is a turbo-diesel like its rivals, but it’s 3 liters and six cylinders vs. 2.0 and 2.1 liters and four cylinders for the X3 and GLK, respectively.
Its power is behemothian: 240 hp and 428 ft.-lbs. of torque – the latter figure being 22 ft.-lbs. higher than the rated output of the same basic engine in the larger/heavier Q7. More directly relevant, the Q5 TDI’s hp and torque numbers wash over the puny-in-comparison outputs of both its rivals:
The X3’s 2.0 turbo-diesel musters a meager 180 hp and 280 ft.-lbs. of torque. That’s 60 fewer horses – and 148 ft.-lbs. less torque. Think of Arnold in his prime . . . vs. Pee Wee Herman in his. 
Torque-wise, the Benz GLK comes a lot closer. Its little 2.1 turbo-diesel whelps out 369 ft.-lbs. Which is solid. But its hp is merely 200 – 40 fewer than you get in the Q5 TDI.
Not surprisingly, the Audi runs like a raped ape while its rivals pretty much accept the inevitable, relax and (try to) enjoy it.
Zero to 60 in 6.5 seconds for the Q – vs. a languid 8.2 for the Benz and about 8 seconds flat for the X3.
Surprisingly, the Q5’s EPA stats are damned close to its much-less-potent/not-nearly-as-speedy rivals:
How about 24 city, 31 highway – vs. 24 city, 33 highway for the Benz GLK?
The BMW might do better – official EPA numbers weren’t available when this review was written in late May – but the same engine in the 3 series (from which the X3 is spawned)Â rates 32 city, 45 highway.
That latter number is better than the Audi’s – but keep in mind: It was obtained in the 3 series sedan – a lighter (and smaller) car, not a crossover SUV. In the heavier, less aerodynamically efficient X3, the 2.0 turbo-diesel will probably return closer to 36 or so highway. That’s good – and yes, it’s still better than the Q5’s highway number. But given that the 3 sedan’s city number is virtual dead heat with the Q5’s, in the larger/heavier X3 it could very well be lower than the Q’s. In which case, the average numbers will be . . . yep, damned close.
Regardless, nothing that’s diesel-engined in this class can touch the Q5’s performance – and not much that’s gas-engined in this class can touch the Q5’s at-the-pump performance while also delivering comparable on-the-road performance.
Audi pairs the diesel V-6 with an eight-speed automatic (same deal in the Benz and BMW) as well as Quattro all-wheel-drive. The transmission features both Sport and normal Drive modes, as well as a driver-selectable manual mode. Like more and more new vehicles, the Q5 comes standard with an automatic engine turn off (and back on again) function that shuts down the engine when the vehicle is stationary – at a red light, for instance – then automatically kicks it back on when the driver takes his foot off the brake (as when the light goes green). This system – which is there to increase fuel economy by limiting wasteful idling – can be turned off or left on, as you prefer.
ON THE ROAD
The Q5’s obvious merit relative to its rivals is its no-compromises performance. It moves – but it doesn’t suck.
The Benz doesn’t suck – but it doesn’t move.
Quickly, that is.
The BMW sucks even less. But it likewise moves without much alacrity.
Their eight-seconds-to-60 times, keep in mind, are under ideal conditions: Just the driver on board, a straight and level road. With three or four people on board – or attempting a pass on a grade . . . well, let me put it this way. The Q5 will be quicker loaded with three or four people – and trying to ascend a grade – than a GLK or X3 will be on the straight and level, empty except for the driver. The Q’s extra margin of thrust means it’s quick when empty – and not slow when it’s full.
The others are.
And, aren’t.
Don’t ever forget the Q TDI’s Herculean torque. No worries – it won’t let you forget. That 428 ft.-lbs? It’s more torque than the current Dodge Ram 1500’s Hemi 5.7 liter V-8 gins up (410 ft.-lbs.) and it comes on right now – under 2,000 RPM and holds it throughout the RPM range. What this means is a light depression of the accelerator results in immediate and forceful acceleration. The Q literally lunges forward like bull trying to get at a cow on the other side of the fence.
The Benz is torquey, too – but not to the extent that the Q is. And it hasn’t got the horsepower to hang once the RPMs climb.
The BMW, meanwhile, is deficient on both counts.
All three of these vehicles handle well, being basically cars made to ride a little higher (and sit a bit taller). In fact, they probably handle better than most of the cars I grew up with in the ’80s. It helps that they’re equipped with what would have been considered race car rolling stock back in the ’80s. The Q, for instance, comes standard with 18-inch wheels (the TDI gets 19s)Â and you can upgrade to 20s (S-Line package).
Of the three, the Q feels lightest on its feet  – not surprisingly because it is the lightest of the three: 4,079 lbs (a veritable featherweight for a crossover SUV) as contrasted with the beefy X3 (4,230 lbs.) and GLK (4,246 lbs.). The Benz, it should be noted, is also the one of the three that’s closest on the spectrum of car-to-SUV to the SUV side of the bar. The BMW, despite its beef, feels – reacts to inputs – with more athleticism than either the Benz or the Audi. But it is let down by its lack of complementary power. The Q can power through – and out of – a corner. The X3 can’t. You mash the gas pedal and not much happens.
Because there’s just not much there.
AT THE CURB
On the lower end – even the bread and butter end – crossovers look depressingly homogenous. As though the stylists used the same basic template for the side panels, then added “branding” cues such as a waterfall vs. horizontal slats grille to manifest their “brand language” (the car company PR people sometimes talk like this).
In the Q5’s class – the entry-premium class – it’s not difficult to tell who’s who. The Audi looks like, well, an Audi – and not just because of the big auto union olympic circles logo in the grille, either. It’s an impressive – but not obstreperous looking – rig. Classy – but not overly flashy. That’s the Audi aura.
And ironically, it looks the hunkiest – despite being the lightest. This may be due to its width being greatest (74.7 inches vs.74.3 for the GLK and 74.1 for the X3) a probably higher beltine (it looks like it), and much wider track, both front (63.7 inches) and rear (63.5 inches) as contrasted with the narrower-through-the-hips Benz (60.7 inches of track front and 60.8 inches in the rear).
This – plus a generous wheelbase (110.5 inches) and close to mid-sized overall length (182.6 inches) also adds up to the most spacious interior of the three: 41 inches of front seat legroom, 37.4 inches of second row legroom and 29.1 cubic feet of cargo space behind the second row.
As contrasted with: 39.9 inches of front seat legroom, 36.8 inches of back seat legroom and 27.6 cubic feet of cargo space behind the second row for the BMW.
The Benz gives you a bit more front seat legroom, but the second row is (and this is typically Benz) the tightest of the three: just 35.1 inches (about 2/12 inches less than in the Audi). The GLK’s other notable deficit is its worst-in-class (or at least, worst of these three) 23.3 cubic feet behind the second row. None of this should be surprising given the GLKL is very much a compact crossover. At just 178.3 inches long overall, it is 4.3 inches stubbier than the nearly mid-sized Audi. Or, to make another comparison, the Q5 is only about 5 inches behind the most definitely mid-sized Lexus RX350 in overall length – and the Audi has a significantly longer wheelbase (110.5 inches vs. 107.9) than the “mid-sized” Lexus. 
The Q’s rear seats also slide forte and aft – which you’ll discover to be a rare feature in this segment.
THE REST
The Q5 TDI is not a cheap date. At $46,500 to start, it is priced $6,595 higher than the GLK BLueTec and $3,675 higher than the X3 diesel. The cost gap gnaws away some at the economic arguments in favor of the Audi – but it does have power/performance in its favor. It’s also literally more car for the money, as noted above.
If size matters to you, that will be a mitigating factor.
As is true generally of diesel-powered vehicles sold in the U.S., the Q5 TDI comes dressed in premium duds – with everything you’d get standard in the gas-burning, supercharged V-6 Premium Plus Q5 except headlight washers and a few exterior trim bits (which you can always add, if you like). That means: 19 inch wheels instead of the base 2.0 Q5’s eighteens, xenon HID headlights, LED running lights, heated seats and a panorama sunroof with full-length retractable sunshade.
You also get standard satellite radio – with a 10 speaker premium audio rig. It must be mentioned that satellite radio is extra-cost in the GLK and X3.
Interesting options include an available heated/cooled cupholder – and the GPS system features a cool but also slightly creepy Google Earth View map that shows not merely the road you’re on but the actual road you’re on. And the houses off to your left or right. And the cars parked there. The level of detail is amazing – and it’s not a computer generated representation or icon. You are literally viewing everything within your radius – up to several miles – as it actually is. Continuously updated. If this level of technology is available to us on the consumer market, imagine the level of technology that’s available to them. The creeps in the NSA and other such hives of the nascent American staatspolizei.
The Multi-Media Interface (MMI) requires multiple inputs from you to find what you want – and to turn it on or off. You scroll through menus using a center mounted dial, then depress that dial to select. But there are also secondary input buttons on all four quadrants surrounding the main dial – plus a smaller knob for radio volume off to its right. It’s not Hulk Smash awful, but it does take some getting used to as well as time and attention to use it once you know how to use it. Same goes for HVAC controls, which are also multi-function. To increase or decrease the fan speed, for instance, you must first click on the little “fan” button. Then you can rotate the knob and dial it up – or down. Otherwise, you’ll be dialing the temperature up – or down. Again, it’s not Hulk Smash awful. But I prefer separate (and one-function) buttons.
You may too.
One other thing: The Q5 TDI will periodically need to be topped off with urea – that’s what the extra filler neck adjacent to the fuel fill is for. The interval will vary depending on the miles you rack up – and how you rack up those miles. But in general, figure once every couple of months.
And figure about $20 or so to do it – if you do it yourself. It will cost significantly more if you have the Audi store do it for you.
It’s not a huge big deal, but it’s part of the diesel ownership experience. Pretty much all diesel vehicles sold in the U.S. (except for some VWs) require urea – called AdBlue or BlueTec depending on which brand of car it is – in order to be “50 state” emissions compliant.  
Finally – and this is not Audi’s fault – some diesel stations still have nozzles that don’t fit the Q5’s filler neck. Be careful – and take note. I had to deal with one such nozzle that had a flared end far too large to mate with the Audi’s filler neck. I had to dribble the fuel in – or else it would have dribbled (or sprayed) all over me.
THE BOTTOM LINEÂ
It’s speedy – but it’s not greedy.
Roomy, too.
Yeah, iIt does cost more than its rivals -but this is definitely a case of getting more for your money.
Throw it in the Woods?
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These comments are all very helpful. I’m vascilating between the mileage and sex appeal of this diesel vehicle vs. the low-maintenance, carefree ownership of the Lexus RX, which has been my vehicle of choice for 10+ years. I’m ready for a change, but am worried that Audi will be less reliable and more expensive to repair. Thoughts?
Also, does the VW TDI scandal affect this vehicle? If so, it will be discounted, eh? And maybe I should wait another year until SHTF and prices drop further…
I’ll have to check the specs, but if this Audi is like all the other Audi/VW/Porsche TDI engines, you’ll only need to add the urea every 10,000 miles or so. If you do a lot of hard accelerating, the kind that would typically generate heavy, sooty exhaust out of a more traditional diesel (like an older Ford PowerStroke), you’ll be generating more soot that will plug up the Diesel Particulate Filter (DPF) and require “regeneration” more frequently but also will require more Diesel Emissions Fluid (DEF), or urea, to be injected due to the less efficient burning of the diesel fuel. So a heavy foot, and driving close to 10k miles, might get you to need to refill every two months, but more than likely it’s closer to 10 months for the average driver. If you buy the stuff yourself, you’ll spend around $10-$20 and can fill it up easily by the gas filler neck. It sucks, and it’s completely unnecessary except for government emissions demands.
As for filling up, having put 40k coast-to-coast in a little more than a year on my VW Touareg TDI (basically the same platform and engine as the Q5, just halfway between it and the Q7 in size), I’ll pass along some tips I’ve learned to hopefully save some others some trouble.
1. The nozzle thing Eric mentioned is true. I’ve encountered this at more than one station. It’s best just to keep an eye out for labeling on the pumps, usually noticeable as you pull up to them, saying something like “diesel trucks only” or some such. These nozzles have a ring around the tip so they can be “hooked” into the big diesel tanks of large trucks and semis. This makes them incompatible with most light duty diesel filler tubes. Better to look elsewhere than to try and trickle-feed your tank.
2. All diesel now sold for on-road use in the US is “ultra-low sulfur diesel” (ULSD). This was mandatory in the US as of around 2007 or so. The only places you’ll find lower quality diesel is leftovers in old diesel storage tanks or on farms and other places where old diesel is kept and hasn’t been used up yet. Off-road diesel, “dyed diesel,” “red diesel,” etc. are intended for non-road going vehicles (tractors, combines, etc.) and the price doesn’t include many of the fuel taxes, so is typically cheaper. You generally won’t find that at service stations. #2 Fuel oil is pretty much the same thing as this red dyed diesel stuff. It’s dyed red so government stooges can check and see if you’re running the non-taxed stuff and fine you for it if you’re on road. Aside from that, at least in theory, you could run any form of ULSD in this Audi and be fine, as they’re all essentially the same stuff. Doesn’t matter what injectors you have. TDI stands for Turbo, Direct Injected, and has been around for 15+ years now. That has nothing to do with why you can’t run older diesel in modern TDIs.
3. Biodiesel is a no-go. Biodiesel, diesel fuel made from grains (wheat, barley, etc. turned into vegetable oil) is extremely clean burning and often much cheaper than regular diesel. This latter fact has to do with the farm lobby and the subsidies that the taxpayers in various states (like Illinois) pay to farmers to turn more of their crops into fuels like ethanol and biodiesel, instead of putting them to less environmentally harmful and more productive uses like livestock feed and putting food on people’s tables. So at least my few experiences in Illinois, the state you’re most likely to see this in, revealed price differences of around $1 less for biodiesel mixes than for straight diesel. Most of the mixes were B20, which means 20% biodiesel and 80% regular diesel. Diesel engine manufacturers are slowly weighing in on how much max they will rate their TDIs for, but VW rates them currently at a max of B3 (3% biodiesel). This is pretty much true for any diesel that has a DPF, or diesel particulate filter. This is also why you can’t run old diesel through a new diesel engine (2008 or newer at least).
The DPF needs to be regenerated periodically, which means all the soot the filter has caught must be burned off. This is done by injecting small amounts of diesel fuel into the exhaust system flow. The heat from the exhaust vaporizes the diesel and then it is set on fire in the DPF to burn up all the soot that has been trapped. Not only is this a waste of fuel, it also depends on a diesel fuel that is volatile enough to vaporize at the temperature of the exhaust gasses. Unfortunately, biodiesel doesn’t vaporize as well (less volatile) and is more prone to clogging up the DPF than to clearing it through regeneration. This can void your warranty. Similarly, using the older “Low sulfur diesel” instead of the new “ultra low sulfur diesel” will produce more soot and plug up the DPF too much, again voiding your warranty.
Typically, regular diesel fuel pump nozzles have a green color to them (as do the pumps). Biodiesel tends to have yellow nozzles and pumps. You can read the biodiesel mixture ratio on the pump without getting out of the car.
4. Price differences. This is one point that may be why diesel is appearing more in higher end car models than lower end models. Ten years ago, diesel typically was the same or cheaper than regular grade gasoline most of the time. The mandate for Ultra-Low Sulfur Diesel (ULSD) has jacked the price up by about $0.50/gallon on average, in my experience. However, these prices vary wildly from station to station along the same road and from region to region in the country. I’ve seen diesel prices vary >$0.40 within a mile radius from quality vendors (Shell, BP, etc.) and often it’s 20 cents cheaper across the street.
The difference, though, between diesel and premium gasoline, which is what most luxury cars will require, is much smaller and is frequently in favor of diesel. Thus you can get a small-engined gas vehicle with poor performance and a little bit better gas mileage that requires premium fuel (the gas powered GLK, for example), or you can get a good performing diesel engined version of the same thing that gets much better mileage at the same time OR a similarly performing diesel engine that gets even better mileage. It’s common to see diesel cost 5-10 cents less than premium gas.
Also, it seems that the price difference between gas and diesel expands during the winter months and contracts come next spring. I suspect this is because they switch to a winter blend which has more additives to keep the diesel fuel from “gelling” by getting too thick/viscous in the cold weather. This is also why diesels need “glow plugs” to heat the diesel in the tank a little bit so it will flow through the fuel lines. Modern such glow plugs are so fast they are barely noticeable. During the summer, on my travels, I’ve seen the cost of diesel still rarely be less than the cost of regular gasoline, but it’s typically closer to mid-grade gasoline. Rarely is diesel more than 20 cents higher than premium. All told, even at the maximum price differences, the better fuel economy of the diesel compared to a comparably performing gasoline engine model will still win out. Except for the up front cost.
5. Range. Trust me. If you’ve got a 26 gallon tank and are getting 29+mpg on the highway, you’ll be going a long way before you need to fill up. You will almost certainly need to pull over for a break, a drink, food, etc. long before you get close to running out of fuel. So passing up a fuel station because they only have biodiesel is not a problem. Just fill up when you get close to 1/8th tank and you’ll be fine. It is the antithesis of the “range anxiety” you get in an electric car. This also means you’ll go as far or farther on a 1/2 tank of diesel than most vehicles will go on nearly a full tank of gasoline, particularly SUVs.
6. Idling. This one I have yet to confirm, but it seems that diesels idle extremely well, by which I mean they burn little fuel sitting stationary with engine running. I haven’t run an experiment yet, but from what I’ve been able to determine with some research, the 3.0L V6 TDI in the VW family will burn in the ballpark of 1/3 gallon per hour. With a 26 gallon tank (which is what my Touareg has), you’re looking at 3 days straight, or if it actually burns closer to 1 gallon/hour, over a day.
Why do you care? If you’re in bumper-to-bumper traffic, spending most of your time at 0mph, you’ll actually be burning much less fuel per hour than the idling gasoline powered car next to you. Not as little as a hybrid or someone who shuts the engine off, but better than most. Odd thing: Remember a few months ago when Atlanta froze up because of a bad winter storm and everyone was stuck in perpetual rush hour, running out of gas on the freeways because their cars were idling? Very good chance, if my information is correct, that wouldn’t have happened if you were in a diesel with a decent amount of fuel on board. Yeah, weird use scenario I know, but something to consider in case of emergency. How long will your gasoline powered car run at idle on a full tank of gas? Ask Atlanta.
Thanks for that detailed, informative post, SJ!
Your point in re the cost of premium unleaded vs. diesel is spot on. There may be a handful of exceptions (possibly, on the lower end, such as the Camry-based Lexus ES, etc.) that don’t require premium – but you’re right that most high-end cars with gas engines demand premium, which is much closer in cost to diesel.
I love huge filler necks at truck stops….gets my 27 gallon tank filled in no time because they pump fuel so much faster at a very high volume
I like ’em too – but watch out if you have a diesel car!
And watch out for the actual fuel at the truck stops in a TDI. Big rigs can burn just about anything above bunker fuel and not complain, but TDIs can be very touchy when it comes to fuel quality, especially late model engines. The direct injection system is the culprit. Older TDIs could run on french fry oil with the normal modifications (and got better milage because of the lack of the soot capture device in the exhaust), but they also had a very different injection system.
I agree with you that SUVs seem like ideal vehicles for these modern diesels. And nobody can argue that this V-6 diesel in the Q5 TDI is an amazing combo of high performance with high mpg.
But this car evokes no desire in me. Perhaps it’s just me ( I bet that I’m far from alone,) but a compact CUV seems slightly “down market.” At a $46,500 “base” price, I want a full sized, “big dog” SUV, that can offer extravagant stretch out room, and more space for more of my expensive possessions. 😉
Hi Mike,
Sometimes, bigness – especially external – can be a liability. I’ve lived in both suburban/urban and very rural settings. In the former, a really big SUV or truck can be a hassle to live with. They eat up most of the typical home’s garage space. They’re not easy to park/maneuver. Something smaller – especially if it’s big inside – can fit the bill a lot better.
What I like about the Q5 TDI is that it so obviously out-classes its rivals in terms of power/performance – as well as prestige, arguably, given it has an impressive V-6 diesel while the others have fours.
Oh yeah, sometimes a little urban runabout is just what is needed. But I question the appropriateness of a monster motor, and luxuries up the wazoo for puttering around in congested environments.
Also gotta question your “big inside” terminology. “Space efficient for it’s compact external dimensions” seems more accurate.
Of course, if cost is absolutely no object, have at it! I think it would be awesome to see this engine shoehorned into a “Smart” Car.
I test-drove the GLK 250 Bluetec when I was looking for a replacement for the lemon Civic, and I liked it a lot. It won’t win many stoplight races (you can leave a Prius in the dust), and you’ll need a trailer to haul the wall-sized flatscreen TV home from Costco, but for a daily-driver SUV, it’ll fit the bill.
The advantage of the diesel came in city traffic – I was able to squirt my way past the Austin slow-pokes with the almost instant-on power of the turbo producing 369 ft-lbs delivered via Mercedes 4Matic all-wheel-drive. And do it while almost matching the mileage I was getting in the Civic.
Ultimately it came down to price – If I were to buy a GLK I’d have a $575 a month car payment and I wasn’t willing to do that (despite it being *very* nice to drive).
As much as I welcome the growing variety of diesel vehicles in the U.S., I’m still more than a bit disappointed that the growth seems focused (as Eric recognizes) on the higher-end market segment.
As a long-time owner of VW diesels (Jetta and Golf), I’d love to see more competitors hit that market AND bring an AWD option with them. The Chevy Cruze is FWD (and loud, to boot), the Mazda6 continues to be delayed. We keep hearing VW make all the right noises about bringing the next generation Golf Wagon in diesel AWD next year, but I’ll believe it when I see it. As it stands, there’s no question that VW is the power player in the non-truck diesel market (and certainly in the non-luxury diesel market), so it’s up to it.
As nice as they are, I don’t need (and don’t want) a $40,000 AWD diesel with all kinds of luxury nonsense. I want a $25,000 AWD diesel — that I can put a zillion miles on without feeling like I’m devaluing something too much — with reasonable options (I’d kill for a Subaru diesel — we’ll see if one ever gets here) that I can use to commute in all weather, including snow, that still gets reasonable mileage and gets to 60 in somewhere in the 8 second range.
But none of that is going to happen until VW either decides to make the leap, or someone decides its time to step into the lower-end market.