msaudiq5

Everybody knows that diesel is great on long trips but does anybody here have real experience to use Q5 TDI mostly for short city trips?
Is it bad for diesel engine reliability?

Thanks

Barraged

I routinely get 26-28 mpg in city only driving...diesels are very reliable and city driving will not place any burden on the engine...

Yoshimura

Need a short-haul grocery getter? Don't pick diesel - The Globe and Mail

“I hate to say it, but I don't think diesel's right for this guy,” says Volkswagen Canada spokesman Thomas Tetzlaff. “They're quiet, they have great acceleration and extremely good fuel efficiency. But they’re really not designed to be driven just five kilometres a day.”

ex-quattro PETE

Yoshi, this is exactly why I decided to stay away from the TDI. My wife has a 3-mile commute.

Then again, even regular DI gasoline engine will probably have issues when driven in such manner. I fully expect I'll have to deal with carbon deposits at some point, given her driving patterns. The engine just doesn't have a chance to stay at normal operating temp long enough to help burn off deposits. But with TDI, you have the additional problem of DPF regen.

Thunder22

I just sold my 2012 BMW X5 diesel because I was using it as a DD and getting crap mileage due to the nature of my commute in stop/go traffic around NJ/NYC and replaced it with a Q5 2.0T gas. I'm getting much better mileage now. The X5 was amazing on longer trips, I made it round trip from NYC to Killington on 1 tank of diesel, but around town I was getting mid to upper teens MPG.

Be careful which advice you take. Hills/stop & go/short trips all kill diesel MPG. Someone with a 15 mile commute on flat roads with no lights? Diesel is fine. 15 miles in/around NYC with a light every block and up/down hills (not that diesel can't handle hills, it's the combo of standing starts and hills that kills MPG), and diesel sucks. I know this first hand.

Add in that diesel engines need to get up to temp and stay there for optimal MPG and short trips are not a great use for diesel.

ex-quattro PETE

But the same is true for gasoline engines.

Thunder22

yes, but it takes diesel longer to get there and stay there, and diesel runs cooler than gas. Diesel engines are also usually heavier than gas.

carkarl

Not sure anybody really can answer the question. Does such short-trip duty cause reliability or maintenance problems with TDI versus TFSI? Sure, when you just make short trips and low miles per month, you get poor MPG and tank range. But, under this usage the MPG is almost irrelevant to total cost. You lose much more on insurance, registration, maintenance, and depreciation. And remember, service is also due by time as well as mileage.

I have a 1999 A4 1.8TQ just now reaching 70k miles on the odometer. I have replaced aging tires, a timing belt, thermostat, various sensors, various seals, axle boots, engine and drive-line mounts, and power steering that have failed or worried me one way or another due to calendar age rather than miles driven. People who drive a lot would think my maintenance history looks insane, since they wouldn't see most of these milestones if they hit 70k miles after just a handful of years.

If prices and depreciation were close enough, a plug-in hybrid or full electric might be better for these short-trip schedules, to avoid running a gas engine at all or avoiding all the engine-related parts and maintenance in the case of full electric. But, my urban environment of parking garages still lacks charging options for plug-ins and full electrics, and I wonder if that will improve in the next decade or two.

AudioBear

I drive a 2014 A6 TDI (37.3 mpg/34K miles) but I would go electric or a hybrid if I lived in a city or did a lot of stop and go driving in a city. Diesels have no advantage there; where they excel as others have said, is the open road.

I don't know how Audi diesels last compared to their gas engines but one of the reasons you see diesels in all sorts of commercial and utility applications is that, in addition to better efficiency, they tend to last longer and cost less to maintain and repair. Now whether this is true for a performance luxury car like an Audi I cannot say. I do know old Mercedes diesel cars were bulletproof, if somewhat under-powered. My brother-in-law put over 500K miles (800K Km) on one without any major repairs. I'd be interested in knowing how Audi diesels compare to gasoline versions on long-term durability and maintenance costs. Has anybody every seen any data on that?

ex-quattro PETE

I know this was true in the past, but does it still hold true with modern turbo diesels? People on here report that they actually warm up very quickly.

Wife's 3.0T gas takes a really long time to get up to operating temp (I'm talking oil temp, not coolant temp). It's hard to fathom diesel takes significantly longer than that.