Regarding: www.honestjohn.co.uk/askhj/answer/69825/bmw-318i---nox-and-cam-shaft-sensor-failure

I too had a 318i (E91 Tourer) and had the same failure occur. I thought I should let you know that on my car, I've always followed your advice on using Shell V Power, and although my mileage wasn't enormous, the bulk of the use was on medium to long distant runs between London and Suffolk.

My problem occurred at five years and 38,000 miles and although out of warranty, my local dealer did (supposedly) obtain a 50 per cent goodwill contribution from BMW, although I still ended up paying close to £600. The dealer hinted it wasn't an uncommon problem.

I disposed of the car shortly afterwards, as I did lose confidence in it as a long term prospect, as it had also got through two coil packs - both replaced under warranty.

I am currently running a 2 Series Active Tourer 218i, which I hope will prove more reliable - I read your advice that the engine has proven reasonably reliable in the Mini. The 2 series has proven far more comfortable (sensible wheels/tyres help) and economical. It really is strange that BMW have failed to sell more of them, even though the dealers are willing to do deep discounts to shift them. I just hope long term reliability is better.