I am the owner of a 2008 Audi A4 2.0T with this exact issue. In November of 2012, with 70k miles on my vehicle, my wife and I were on the highway with the cruise control set and BANG! After attempting to start the car for 3-5 minutes, my wife grew concerned about sitting on the shoulder of I-355 in Chicago, with an abundance of traffic flying by us. I had the car towed to a local mechanic. The cause of the catastrophic engine failure was a faulty timing chain tensioner which slipped and bent all of the valves in the cylinder head. There was damage to 3 of the 4 pistons due to impact with the valves. The engine was scrap metal. Up until this point I had my oil changed every 4k miles (more frequently than required by Audi and for a vehicle running synthetic oil), there was no warning and I had never had a check engine light. The mechanic contacted Audi and they refused to cover the damage under warranty, I do not remember if it was due to milage or some other circumstance.

I purchased a lightly used engine with 25k miles, out of another 2008 Audi A4 2.OT. It was a relatively good deal with installation and only cost me $5K. In August of 2014, with 45K miles on the lightly used engine and once again driving along at 60mph on the highway, the second timing chain tensioner slipped. I had it towed back to the same mechanic, the shop has an excellent reputation and I have had them work on my cars for the better part of 15 years. I explained that I believed the two events were very similar, the engine sputtered a couple of times and then made some loud clanking noises and finally shut off and would not restart. The mechanic pulled the timing belt cover and informed me that I was correct, the timing chain had slipped again, hanging off the gears. He used a scope to verify, and once again, every valve was bent, and there was impact damage on the domes of the pistons. The car is currently parked in the garage, as it is in pristine condition, except for needing an engine. I have been considering purchasing a third engine for it, as I enjoyed the comfort, liked driving the A4 and there is some sentimental value to it. My dad paid off the balance that I still owed on the car, as a wedding gift, when my wife and I wed a few years ago. I'm not going to scrap the car.

While shopping for used 2.0T engines online, and researching the timing chain tensioner to see if this was a known issue, this site came up.

I wish you all the best of luck working with Audi towards a solution and am thankful that no one has been injured as a result of these failures.

I am sorry to read about other similar incidents. I feel inclined to add my story for a few reasons: additional information may be useful for ongoing class action lawsuits; to dissuade anyone who is considering purchasing one of these vehicles from doing so; and to let the other commenters know they are not alone in their frustration.

I am the owner of a 2008 Audi A4 2.0T with this exact issue. In November of 2012, with 70k miles on my vehicle, my wife and I were on the highway with the cruise control set and BANG! After attempting to start the car for 3-5 minutes, my wife grew concerned about sitting on the shoulder of I-355 in Chicago, with an abundance of traffic flying by us. I had the car towed to a local mechanic. The cause of the catastrophic engine failure was a faulty timing chain tensioner which slipped and bent all of the valves in the cylinder head. There was damage to 3 of the 4 pistons due to impact with the valves. The engine was scrap metal. Up until this point I had my oil changed every 4k miles (more frequently than required by Audi and for a vehicle running synthetic oil), there was no warning and I had never had a check engine light. The mechanic contacted Audi and they refused to cover the damage under warranty, I do not remember if it was due to milage or some other circumstance.

I purchased a lightly used engine with 25k miles, out of another 2008 Audi A4 2.OT. It was a relatively good deal with installation and only cost me $5K. In August of 2015, with 45K miles on the lightly used engine and once again driving along at 60mph on the highway, the second timing chain tensioner slipped. I had it towed back to the same mechanic, the shop has an excellent reputation and I have had them work on my cars for the better part of 15 years. I explained that I believed the two events were very similar, the engine sputtered a couple of times and then made some loud clanking noises and finally shut off and would not restart. The mechanic pulled the timing belt cover and informed me that I was correct, the timing chain had slipped again, hanging off the gears. He used a scope to verify, and once again, every valve was bent, and there was impact damage on the domes of the pistons. The car is currently parked outside of the garage, as it is in pristine condition, except for needing an engine. I have been considering purchasing a third engine for it, as I enjoyed the comfort, liked driving the A4 and there is some sentimental value to it. My dad paid off the balance that I still owed on the car, as a wedding gift, when my wife and I wed a few years ago. I'm not going to scrap the car.

While shopping for used 2.0T engines online, and researching the timing chain tensioner to see if this was a known issue, this site came up.

I wish you all the best of luck working with Audi towards a solution and am thankful that no one has been injured as a result of these failures.

Update from Feb 23, 2017: Posted date of timing chain tensioner failure was November of 2012, an error was made during initial setup of this complaint stating November of 2011. Also the milage was stated at 65,000, milage was 70,000 miles.

I'm a technical person, hopefully you won't get lost through this.

Variable Cam Timing adjuster assembly - this is the cylindrical metal assembly mounted to the rear of the exhaust camshaft of the 2.0T engine. It is "secured" to the cam by a relatively thin soft-steel bolt and a conical screw. This metal adjuster circulates engine oil (which is pushed here by the engine's oil pump) through it, and based on velocity of engine and centrifugal force exerted by the metal assembly itself, the oil inside it will change pressure... there is an electronic pressure sensor (for lack of a better "layman" description) that reads the oil pressure from this metal assembly, and advances the engine's timing based on that...

This is an extremely poor design (set timing solely based on an oil pressure sensor) - Audi already has a position sensor key on the front of the intake cam, so why not use the same for the exhaust cam, instead of relying on a SECOND oil pressure sensor? I know that the intention was to cut power in the event there is low to no oil in the engine, but drive everything off of a single sensor? C'mon! It looks like high school grads with no technical supervision and no holistic view designed this engine.

Well... if your "skilled" Audi shop mechanic does your front timing BELT replacement and skips more than a tooth there, the timing will be off.. valves will hit the cylinders, they will jam the camshaft, which in turn will shear the holding pin of this Variable Cam Timing Adjuster assembly... and from there on it becomes a $4,000 and up engine repair job (starts from a cylinder head assembly repair to an entire engine replacement, which will easily reach $9,500 + tax)..

I've worked on many other cars before, but this is the worst design I've ever seen. Junk auto mfg's do their engines better than this one.

Knowing this was a poor design, I hoped that Audi would cover this under the warranty - but instead I'm reading reports from all over the web that they didn't, and that they passed all repair costs to the consumers the instant the factory warranty expired.

It seems Audi took the hint from all other auto MFGs and replaced the front timing belt with a timing chain - but that was at least 10 years after everyone else did it... 2009 and newer models of Audi no longer have the rubber timing belt, so I guess this is no longer an issue.