ok so i got an 86 325e coolant seems to be clearly coming out the overflow quite abit like in a 25 min drive ill loose all the expansion tank and some! i replace coolant sensor a few hoses expansion tank cap and the tank with a used one. also theres no signs of a head gasket where should i go next? thanks in advance!

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Actually it sounds like a bad head gasket. The cooling system is over pressurizing and forcing coolant out of the tank. Is the vehicle overheating. You could also have a bad water pump allowing the engine to overheat and cause the coolant to boil over.

- Kerry