coolant problem

[ciaran]

2 days ago my 01 lbw 359 transit started to blow cold air through the vents in the cab when on full heat. was told the coolant might be low. so put in about 2l of coolant then the van starts to over heat only when i turn on the fan to blow air. another thing when i look in the tank there dose not seem to be any coolant like it has leaked out somewhere. the van is not not smokey and no signs of a leak on the engine. really need help thanks

[ake]

You need to find out where the coolant is going, oil cooler is a favourite, also egr cooler

[ciaran]

i went out this morning it took 6l there is no trace of water around the van. how will i find out if it is in the intercooler. it has been about -10c the last few nights here in ireland

[chooseatransit]

have you checked your oil level

[ciaran]

oil is ok. now the expaansion tank is continuely bubbling with air. this only started to happen after i took the top of the thermostat and pushed it down put it back together and then the new problem. is it working out a big air lock.