5748 water temp prob

[greg_5748]

After an hours driving the water temp slowly creeps up until the rad blows the water out, now I have changed the rad cap for a new one but it still happens so which should I look at first the water pump ( which sounds fine) or is there something else ive missed???

 

[dave_peters]

Clean the radiator first, blow air the "wrong" way from back to front and clean the fins. if that isnt effective take off both hoses and back flush the rad with as high a volume of water you have available. There are propretery radiator cleaning products on the market, but I find that a couple of spoonfuls of dishwasher powder in hot water left in the rad for an hour or so works just as well.
Also take the thermostat out of the top hose and put it in a saucepan of water and bring to the boil, if it doesn't open at around 80* C then replace it.
Hope this helps, Dave