Hi i have a 2001 325I , I REPLACE THE THERMOSTAT AND TOP AND LOWER HOSE, AFTER THAT I START THE CAR AND START OVERHEATING ,TOP HOSE IS HOT , BUT LOWER IS COLD , CAR STILL OVERHEATING , BUT NOT BEFORE I REPLACE THE PARTS , ??? ANY HELPP

If your engine is overheating, Try this procedure:

• Dirt and debris can get lodged in the radiator air flow paths. This can block the radiator and cause your engine to overheat and damage the engine.

• The thermostat can be stuck close. If you feel the upper hose very hot and the lower hose cooler than normal, it may be a stuck thermostat.

• Make sure the radiator and the overflow bottle are filled to the proper levels.

• Bleed air from the coolant system:This is best done by running the engine with the radiator cap off until you see when the air bubbles stop coming up.

• Check the radiator fans: The easiest way is to turn on the cars air conditioner and turn up the A/C fans. Both radiator fans should come on when the A/C starts

• Make a pressure test by using a pressure testing tool (available at most auto parts stores). Use the pressure shown on your radiator cap. Most cars are 16 PSI or less, so don't exceed that pressure. Replace the radiator cap if it doesn't hold the pressure.

You need to bleed the system otherwise the antifreeze will not flow to the engine.