My Fiat Punto regularly has trouble starting, especially on cold/damp mornings. It makes a sort of metal grinding noise. I have had a new starter motor which hasn't resolved it. I find it is better if I make sure wipers, lights and fan are turned off.

It is intermittent though and my local garage cannot identify the problem. Also, often on starting the warning of excess radiator heat comes up, even when freezing temperatures outside and car not driven for 8+ hours. Can you help?