Around the world users consumers are turning to forums and technology web sites to complain that their new pride and joy is cooking in hot European and US summers. Launched on June 19, some iPhone users have complained that the device has become too hot to hold to the ear during long calls while others have noticed that the white 32GB model has turned pink after overheating.

In a warning posted on an Apple site users are advised not leave their phones in a car where temperatures can exceed the -20C to 45C range that the iPhone 3G and iPhone 3GS models were designed to function in.

Apple says that "if the interior temperature of the device exceeds normal operating temperatures, you may experience the following as it attempts to regulate its temperature: the device stops charging, display dims, and/or weak cellular signal".

One hot a built in mechanism triggers that tells users that the iPhone is becoming too hot. It's also emerged that the phone may overheat when left in direct sunlight for prolonged periods, when GPS tracking is used in a car on a hot day or when its iPod function is used in direct sunlight.

iPhone 3GS users on Mac forums have lodged several complaints, that the handset have become hot when not being used in a car. In a posting on the macrumors.com forum, one user complained that using the new device's video recording feature had caused it to overheat while another complained that after carrying his phone in a backpack, it got so hot that the plastic case became distorted with tiny bumps.