I have a 2005 tdci 130 which is losing coolant, at least a litre a week. There is no visible leak, and when running the engine I cannot see anything coming out. Any ideas? Also having intermittent starting difficulties, sometimes fires then cuts out, other times turns over once then sounds like battery is flat, only to start up perfectly on the next turn of the key. Not sure if the two problems are related. Any suggestions appreciated.