2007 Audi A4 S line, Amazing condition, Has motor noise

I have an 07 Audi A4 S-line 2.0t Quattro that is in amazing condition inside and out and driving. It always was tight and didn't have any suspension noises or lights on the dash. It drives like a 20k mile car. Looks as well. The leather is in great shape with really no wear and no tears at all. There is no wear on the dash or window buttons like most. Everything works as it should. It is all power including seats that are heated. Sunroof. Headlights turn and aim with the steering. You can open and close the windows and sunroof with the keyless remote. Navigation. Bluetooth for your phone. Memory stick slots for music as well as an aux jack. Paddle shifters on the wheel. I'm sure there is more. Tinted windows. We just replaced the liquid filled motor mounts and oil cooler/filter housing totaling almost 1000 dollars. Last year brand new wheels and tires and the timing belt and water pump. This car is very well taken care of with receipts and records. It has a fair amount of stone chips in the front end but no rust or damage anywhere. It's a super nice car as a whole. It looks so nice. We drove it every day but the other day it developed a loud knock in the motor. No dash lights on but I can't afford to fix it or have the time. We hate to sell it as we love this car. Please ask any questions you may have. I want to keep perfect feedback and have nothing to hide. It is sold as-is and will require a 500.00 non refundable deposit at the end of the auction with the balance paid when it's picked up. It will need trailered as it starts and runs smooth but I wouldn't drive it anywhere but on a trailer. Again please ask any questions. Thanks.