Simplest Maintainance Task Gone Wrong
 

OK, this is the second time this happens and I still don't believe it's happening. How complicated does flushing and adding coolant to an 89 e34 can be?!! I decided to clean out my radiator and re-adjust coolant/water ratio for the hot weather. I drained the old fluid, added some coolant, ran the engine and added the rest. I know I'm supposed to unscrew the plastic screw near the radiator cap and when the engine warms up, it should release all the extra air from the engine.

Well, after the engine warmed, vapor was being released from the little hole as supposed to. But suddenly the engine started over-heating and I had to turn it off. This is the second time it happens. The first time, I brought a mechanic to do it and all he did was take out the screw and add coolant until it shoots out from the hole. I did the same thing but still over-heating. Any advice?

Open the screw.

Add coolant then squeeze the hoses, repeat. You should be able to hear the bubbles in the system.

Start it and make sure the screw is open and the heater set to hot.

first things first. turn the heat in the car to full on hot. then remove the screw, is there also a screw on the thermostat housing? a metal one possibly. fill untill coolant comes out of the hole. run car increasing idle then crack open srew and close quickly. if only coolant comes out then you should be good, it air first continue to run and crack the screw