2004 Audi A4 1.8T engine sludge--complete engine failure. Audi absurdly refuses to honor their own extended warranty on the basis the car was run without oil. The engine failed internally because there was and is sludge blocking lubrication ports to the moving parts, I.e., failure. This is my executive synopsis, but I have volumes of supporting evidence, unbelievable as it is to think this could happen in America.

- Summerville, SC, USA

I have owned my 2004 Audi A4 1.8T quattro for four years. The problem that I am having is a massive issue that hundreds if not thousands of other B6 platform owners also have, the water pump in our vehicles is very prone to failure. The water pump found in our us market vehicles has a plastic impeller that is known to snap, crack, or leak causing the part to fail. I have had two of these pumps fail in the past two years. The first one failed at around 74K in July of 2008 when the part was nearing it's replacement date. The second failure occurred in January 2010 at roughly 98K miles. So I have had two failures in a very short time period. Now Audi is fully aware of this but has never had a recall or even acknowledges that it is their fault for releasing a poorly designed part. When a pump fails it usually goes very quickly. In my case it leaked and then I lost ac compression. I am lucky that I know cars and knew to immediately park the car and get it into the shop. I know that many other people have had significant engine damage because the failed pump caused overheating. The pump is also part of the whole system that drives the timing belt so a failure could also cause catastrophic engine failure if that belt seizes up. Overall it is a huge problem and each time a pump needs to be replaced the entire timing belt service needs to be performed which runs about $1700 at a dealership and around $800-$1500 at independent shops. I feel that this is very unfair to us as owners, but that it also puts the public at great risk if a failure occurs at highway speeds or in traffic. Lives are already at risk enough on our highways and the last thing that I want to do is cause bodily harm or property damage because a company released a poorly designed part and did nothing to improve it. I request that the NHTSA look into this issue. If you search sites like audiworld.com and audizine.com you will find lots of information and first hand accounts.

- Jessup, MD, USA

2004 Audi A4 w. approx 38,000 miles. Failures involve plug & leaking water pump which ruined timing belt. Total charge for repair: Approx $1700.

- Cincinnati, OH, USA

I have a 2004 Audi A4 1.8T. This exact model is what is described in the Audi manufacturer's 8 year extended warranty for engines. I am currently being denied warranty coverage for the engine sludge that has built up in the engine. The reason being according to university Audi in seattle, is that: My car is "too new." But it is a 2004, the cut off year for the extended warranty.

- Renton, WA, USA

Ignition coil failed in one cylinder on 2004 Audi A4 1.8T quattro. This part on Audi repeatedly fails. Loss of power, very shaky at idle and acceleration. $400 to repair, but now catalytic converter is ruined due to the cylinder misfiring.

- San Diego, CA, USA

Engine has an repeated but intermittent loss of power. Usually occurs shortly after starting the car and before the temperature gage shows the engine running at normal temp. Engine continues to run, but when pressing gas pedal all the way to the floor, there is insufficient power to move the car. Also, when in neutral or park, RPM barely goes above 1500 when pedal fully depressed. After waiting a few seconds for sometimes as long as a minute, engine will regain power and will then operate normally. This has happened at least 10 times from oct07 (when purchased car used) through 22 April. Manufacturer technician is unable to locate problem.

- Irvine, CA, USA

I am having ongoing major issues (equipment and safety) with my Audi A4 cabriolet with no resolution from my local dealer or Audi customer care agents. I have had my car towed three times in three months. Most recently(July 21) my car was undriveable, leaving me stranded 2.5 hours from home. The engine started to "skip" and "miss" the check engine light started flashing and the check oil indicator came on. I managed to get off the highway into a parking lot. The person with me can verify that the engine/car felt like it was bouncing or vibrating. Prior to that, my car stalled in the middle of interstate 264 in Norfolk, va. It was a near death experience trying to get out of the middle of that highway. The car stalled when I was leaving work. I decided to try to make it home once it restarted. Once I started to accelerate onto the interstate, the car would sporadically accelerate. It felt like a "stop and go" situation. It progressively got worse over a distance of about 300 yards, finally stalling. The dealer said they could no replicate the problem. Audi refused any further action on my car after repeated requests. The first time my car was towed was from my own local street: The safest place of three locations where I've been towed. The dealer maintains they can not find a problem for the second and third tows. I fear for my own safety to ride in this Audi car. Family members now refuse to ride in this product. Friends and co-workers have witnessed the problems first hand as well. I have made repeated requests to audio customer care to: 1. get the car repaired properly 2. replace the engine 3. extend the warranty 4. offer a reasonable trade-in 5. buy back the car I have been rejected all along the way. I am again begging and pleading for someone at Audi to offer reasonable help here. I'm not asking for much. I'm simply asking for a car that runs to any acceptable standards where I can believe I am safe. Please help.

- Virginia Beach, VA, USA