Overheating please help

GIBBO123

MEMBER
BMW

Hi I currently own a bmw 520i se [e39] 1997. Vin BH 31436. I have owned this car for about a year now and had no problems until now. I had just driven about 20 miles when the temp went to red all of a sudden. When I pulled over found the rad had blown. Got a mechanic to take it away and had a new rad fitted. When I picked up car I drove it home about 15 miles no probs[or I thought] untill I got home and heard strange noises from engine. When I looked, saw water bubbling and coming out from cap on top of expansion bottle. Thought maybe cap had not been put on correctly. So refilled water and bled system only to find I cant drive the car more than 2-3 miles without it overheating and spewing water from the cap. I have checked all hoses, changed thermostat. When the car is just ticking over it doesnt seem to overheat. Im finding that when I take off the two bleed screws, the water would rather seep out from cap than come out of bleed screw holes. There are no colour changes in water or oil. So im at my wits end. Please please help thanks. Andy

2 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Try bleeding it longer this time and follow below

Always bleed air from cooling system after replacing coolant. Set heater for maximum heat. Remove radiator cap. Loosen drain plug and remove drain bolt (if equipped) from engine block. Drain coolant reservoir. Fill coolant reservoir to MAX mark with 50/50 water-coolant mixture. Loosen bleed bolt and fill radiator up to base of filler neck. Close bleed bolt when coolant flows out without bubbles. Tighten bleed bolt. With radiator cap removed, start and operate engine to normal operating temperature. Add coolant if necessary and check for leaks.