Hi - this is the first time I've used this forum so here goes... I have a 1999 318ti Sport Compact. I got the usual symptoms of a blown head gasket - lots of steam out of the exhaust, coffee coloured sludge in the oil etc., so used a sealing product which seems to have done the trick. I've also changed the water pump, the thermostat and the radiator but my problem continues with the fact that the car continually overheats. I keep bleeding the radiator (removing bleed screw and slowly topping up expansion tank until the bubbles disappear from the bleed screw outlet, then topping up again) and I can drive approx 6 - 8 miles then the car starts to overheat. Very occasionally it will correct itself but the air coming into the car is cold, although I did notice today that for the first few seconds after turning on the air vents it was warmer than it has been, but then it went cold again. Every time I bleed the system I have to use approx 2 litres of water to top up again. I'm only using water for now as it's getting very expensive whilst still bleeding the system using anti freeze! When the car is hot, the water is bubbling away in the expansion tank. I don't seem to be losing it anywhere though which is really baffling. Could this be the heater matrix causing a problem? I'm a single mum and have done all the work so far myself to try and avoid costly garage bills, so any advice would be truly welcomed! Thanks in advance.