I was driving my Ford Ka Mk2 and the revs started dropping, with blue smoke coming from the rear of car. The following day, I started it up and blue smoke was still coming out. I took it to a garage and they said it was because it was overfilled by five litres of oil. Is this right because I can’t believe it! Jayne Newbury Without checking your oil level, it is difficult for me to say if it was overfilled or not, but I can confirm that overfilling the engine with oil will give the symptoms you have. If you have been topping-up the oil and the level has not been dropping, this may get you to this situation. If this is the case, draining down to the correct level should rectify the problem. It may still take a few miles after draining down the oil before the blue smoke subsides completely, but hopefully no long-term damage will have occurred.
If the oil has not been topped-up or overfilled, then it will need investigating to discover why the oil level has risen. If your Ka is a petrol model, the oil level rising of its own accord would be very unlikely. If your Ka is a diesel, then a fuel problem may be the issue, allowing diesel to leak into the sump and raise the oil level.