Recently bought a 98 (S) reg Astra 1.7TD LS Estate with 193,000 on the clock. Changed the oil and air filter, no problems. I then bunged some diesal clean in the tank and gave it a really good run up M5 to Wolverhampton to see the footy with a mate. Saturday morning I tried to start her up and she wouldn't fire! The engine kept turning over and then finally she fired up in a massive cloud of smoke! Once fired up she is as sweet as a nut and drives much better for the clean out. What did I do by putting that stuff in the tank?!