well i have a 1999 bmw 328i and its overheating seems alot of pressure build up i replaced upper radiator hose that blew off from the pressure and cracked and bought a new thermostat well the thermostat didn't fit . so i left it out to see if it would still overheat guess what still overheating bad when i feel the upper radiator hose its hot and very hard alot of pressure build up thats what blew it off the 1st time i also tried flushing the radiator? i think i did it right but still overheating please help!

lewis, September 2009

Remove and check the water pump.
The vanes often break off inside, if that has happened you will need a new pump.

fse879, September 2009

thermo switch may of failed this will also make the engine overheat because when the water in the engine gets to a certain temperature the thermo switch operates the fan and cools the water going around the engine quickly or may be the fan is not working to test this remove the plug from the fan now find a flexible piece of wire and hold the wire across the the connection plug make sure the engine is switched on remember to keep your hands back from the fan if the fan works put the plug back on to the fan and buy a new thermo switch you may have to drain the water from the engine if the fan is not working replace fan not thermo switch.

noel, September 2009