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For more than 20 years, the Audi A4 has been one of the German automaker’s most popular luxury cars. With a reputation for reliability and owner satisfaction, it’s no surprise the A4 remains one of Audi’s flagship vehicles. But as it turns out, the most common issues Audi A4 owners have may prove otherwise. We looked across the range of Audi A4 models to find common problems you’ll want to look out for if you’re considering this German luxury compact.

Excessive oil usage plagues most Audi A4 models

Overall, Audi A4 owners’ most common problem, per Car Complaints, is excessive oil usage. It’s a general Audi (and VW) problem, appearing in nearly every A4 model year. The 2.0-liter Audi four-cylinder is known for losing oil, most often via a failed crankshaft seal. Rear main seals are another common contributor to the Audi A4 losing oil. That seal, located where the engine meets the transmission, is one of the most common issues with any EA888-engine car, including modern Audi A4 sedans.

However, the A4 can also burn oil thanks to weak piston rings (See below). Though most model years have complaints of excessive oil usage or burning oil, the problem appears worst in the 2011 Audi A4. According to Car Complaints, this problem happens around 64,000 miles. In total, it costs owners an average of $6,000 to repair, earning a severity rating of 8.0 (out of 10).

Certain Audi models are prone to engine failure

Though the 2002 Audi A4 has fewer complaints than many other model years, it is where the A4’s second-worst-rated problem exists. The only reason engine failure is not the top-rated problem is because fewer owners run into such severe problems. But engine failure earns Car Complaints’ severity rating of 10.0, the worst rating possible. The average Audi A4 repair cost in 2023 is $8,500 and the problem arises at an average mileage of around 66,000 miles.

Timing tensioner failure is the most common cause of engine failure problems in the Audi A4. When the timing tensioner fails, the engine can jump timing and cause catastrophic internal damage. And owners report that this problem can bite in as little as 50,000 miles, depending on how hard you drive your car.

Bad piston rings hinder Audi A4 reliability

This complaint isn’t as common, but is extremely costly. While only two out of nine owners of the 2012 Audi A4 report experiencing a bad piston rings, the problem earns Car Complaints’ severity rating of 10.0. This problem occurs at a low average mileage of around 48,000 miles and costs around $8,500 to fix, despite being some of the cheapest parts in the engine. Often it involves a complete engine replacement, as both the piston and engine block receive damage.

Engine problems are the worst-ranked category across all model years of Audi A4, receiving more complaints than any other category. In fact, the vast majority of complaints about all A4s fall within this category. For example, 25 out of 33 total 2009 A4 complaints are engine-related. The same is true for 2011, where 19 out of 22 complaints involve engine problems. It’s expensive, too; the most common engine problem costs an average of $7,000 to fix and happens at an average of fewer than 59,000 miles. 

What are the least reliable Audi A4 years?

Joe King (Head Audi India), at the launch of Audi A4 2016
The Audi A4 | Raunak Dave/The India Today Group via Getty Images

According to the model year comparison on, the 2009 Audi A4 has 33 complaints, making it the worst overall. While that’s an obvious model year to steer clear from, Car Complaints actually rates the 2011 A4, with 22 complaints, as the “Worst Model Year”. Their reason? In short, the 2011 Audi A4 has expensive problems earlier in its lifespan than most.

Is the Audi A4 unreliable?

While the problems some owners are experiencing are severe, the Audi A4 still has an impressively-low number of owner-reported complaints. Out of model years 1996-2020, the majority have fewer than 20. Overall, the Audi A4 proves to be a generally reliable vehicle. In fact, out of every new luxury compact car tested by Consumer Reports, the 2020 Audi A4 is ranked overall as the best, with an impressive score of 88 (out of 100) and a perfect predicted reliability rating of five (out of five).

Related 5 Unreliable Audi A4 Model Years To Avoid, per Real Owner Complaints

5 Unreliable Audi A4 Model Years To Avoid, per Real Owner Complaints