I am new to this so hopefully posting correctly. My Audi a4 avant 2.0 tdi 6 speed 05 reg lovely car, but what an expensive problem firstly being a BLB engine we had to replace chain driven oil pump for gear drive about 3 years ago. Now it died on A3 in fast lane, no warning, running perfectly, then stopped like key was turned off. Turns out the cam belt has come slack, the tensioner has come off ! Or nearly off. The bolt that holds it pulled out of the cylinder head, threads gone. It's been in there 3 years ok, so why now? the above has resulted in pistons hitting valves and breaking rollers, showering inside of engine with tiny rollers. dont know if valves are damaged, don't know if we will ever find all rollers, and too risky to take chance we have got all them. Big problem, not sure what to do. Anyone had this before? Have read about one similar where bolt came loose, but this has damaged threads and pulled out. Very expensive problem again, on car with about 80k miles. Not amused.