I would start by saying that we love the Mazda CX-5 Sport Nav we have except for ONE thing... the engine. It all started okay, until we had 1170 miles on the odometer and it was 6 weeks old. My wife cold started the engine as per normal except for one thing... It started on 3 cylinders with the most horrendous heavy metal banging from the lower part of the engine, such that I made her switch it off as I feared imminent catastrophic failure, it really was that bad.

I have driven all types of vehicle over my 45 year driving career from 2 stroke 50 cc Mopeds up to Articulated Heavy Goods Vehicles (trucks) and everything else between, Spent 13 years in the Motor Trade as a fully skilled Motor Vehicle Technician before changing Career paths. In all that time I have never heard a noise like this in any engine until now.

The CX-5 was uplifted to the Garage where we purchased the vehicle for investigation as to this problem, the technician informed us that according to the computer there was no fault found.. No surprise as it was mechanical not electronic and no computer is going to acknowledge mechanical problems in it's software.

Since it made this noise I have videoed each start up from cold, with a number of them having the 3 cylinder with banging engine noise, others ranging from 800 to 1800 RPM and no noise at all which I have presented to the Garage and forwarded to Mazda UK.

In turn I was informed that the latest Skyactiv diesels can have 'piston slap' on initial start-up from cold under certain circumstances. Piston Slap ? No Kidding this sounded like a Piston break up and in an engine which has covered less than 2000 miles yet has been with today's technology built to limits of microns in which piston slap should never occur. That is a problem for high mileage engines due to wear between bore and piston skirt.

Despite presenting all the video evidence to Mazda UK all we have been offered is an Injector check followed by a Compression test both of which proved nothing other than both components were working, again no surprise to me.

I am now in the process of using a Mazda CX-5 demonstrator to the same specification as ours for comparison for 2 weeks, on the first day the demonstrator was markedly different from our own CX-5 in terms of cold start up,engine liveliness, acceleration, kick down placement and MPG.

I firmly believe we have an engine in our CX-5 which is what we call a 'Friday Nighter' and is problematic having a major cold start problem that Mazda are not addressing with any urgency, I do know that another CX-5 owner does have the same 3 cylinder start-up and heavy rattle and has contacted me regarding this.