Hi I have an S reg Renault Megane 1.4 which is losing water but I'm unable to find any obvious leak. I topped up this morning before going out on a round journey of about 20 miles. In that time I lost at least 2 litres of water and the heater hardly got warm but by the end of my journey was blowing cold. The engine didn't start to overheat but when the thermostat initially opened the engine temp went higher than usual but quickly fell to normal after it opened. I've checked hoses etc but can not find any obvious signs of leaks. I've been told that it could be a blown head gasket but the car is not down on power and the oil doesn't appear to be contaminated with water. This has been going on for about 4 or 5 days now and I'm hoping someone has a few suggestions as to the cause.
TIA Phil