1996 406 cooling ?

IIRC it's about a gallon but the Haynes BoL is in the garage at the mo and it's too far from the computer to get it. You could do what I do and premix the antifreeze and water in half gallon [1.257] lots before refilling. That way you only put in as much as you need and you have some ready mixed if you need to top up at a later date. Also by only doing half gallon lots you don't waste too much if you don't need it all.

Thanks for the input. I filled the system up today with some 6-7 liters. The problem now seems solved.

David.

Did you use an old plastic pop bottle with the bottom cut off (or similar) sealed to the filler to raise the filling point. This is necessary because there are parts of the cooling system that are higher than the filler and you can be left with an airlock which can lead to expensive damage if the engine overheats.