ISTANBUL, Turkey - 'Luscious Liz' has been replaced by 'Randy Mandy' in Sebastian Vettel's affections.The German F1 driver has a habit of giving female names to his cars and needed to come up with a new one after Red Bull found a defect in the chassis he had used in the season's six races so far.The 22-year-old, who is level on points with championship-leading team mate Mark Webber, will have a different car in Turkey this weekend. The old car was dubbed 'Luscious Liz', following on from 'Kate' and 'Kate's Dirty Sister' last season, and the question before Istanbul was what name would be selected this time."Randy Mandy," the driver announced with a sly smile to a crowd of reporters gathered round in a steamy Red Bull motor home. Webber has won the last two races from pole position and leads the standings by virtue of having won two races to the German's one.STARTED WELLVettel said it remained to be seen how much the unspecified defect had cost him but it clearly had not helped in Spain and Monaco. "Apart from that, we found some other parts that were broken so I wasn't happy in the last two races in particular so we need to see."It's difficult to say (how much difference it made)."Vettel said he had been complaining for some races that all was not well with the car and was gratified when the team discovered the problem after Monaco. "I think it explains a lot and on top of that we found also other things that weren't in proper shape any more," he added."It doesn't mean that we come here and everything is solved, we still have to work hard and try our best to be at the front again."Red Bull have started every grand prix this season on pole position, while Vettel took the top slot in Turkey last year only to lose out to Jenson Button's Brawn in the race. Asked whether he had been surprised by Webber's sudden pace, Vettel turned the question around: "Whereas he always seemed to be quite happy, I wasn't," he said."We need to see this weekend, but I think he did a very good job. It's good to have someone who is pushing." Vettel cautioned against expecting Red Bull to be in a league of their own this weekend and pointed out that there had already been four different championship leaders in six races."If you look at the gaps, it's not that we are massively clear," he said. "It's three points to (Ferrari's) Fernando (Alonso) in the drivers so you never know what happens. "In terms of performance we are looking strong, so that's a good thing. So we should be in good shape for this weekend but I am not really a big fan of using words like unbeatable. Things change too quickly in Formula One."