Hi All My car is a Sigma-engined 270, a year old, having had its first service back at the factory a few weeks ago. Went out for a sedate drive yesterday (Mrs M was on board). All seemed fine, temp around 90deg. Was out for an hour or so. Got back and a few minutes later I noticed a small puddle of coolant under the front of the car. Just spent a while investigating...No evidence of any leaks from any hoses, but lots of splashes around the expansion bottle. When the engine is cold, the level in the expansion bottle is fine, just above the min line, so I figure it can't have lost a huge amount yesterday. I ran the engine up to temperature. There is a steady flow of coolant back into the expansion bottle while the engine is running (I'd estimate the flow to be about a teacup or two a minute), but gradually the expansion bottle fills up and eventually, after about 10 min of idling, overflows through the filler cap. I switch off, and as the engine cools, the level in the bottle drops - it's 20 min later now, and the level is now almost back to where we started. Could there just be too much coolant in the system, or maybe there's a blockage somewhere causing too much to flow back to the expansion bottle? Any idea how much should be flowing back to the bottle during normal running? cheers Jon