Car overheats after about a 15-minute Drive

[FREAKx13]

Hey there so I just bought a 325Ci 2004 with a cracked expansion tank and a leaky lower hose brought it home replaced all of the faulty parts and now it overheats after about a 15-minute Drive. I've bled the system remove both thermostats rebled the system and it still overheats. It's not using coolant so I don't have to fill it there's no white smoke and the compression is good. If I'm not moving I can keep it running for much longer like when I bleed it. I've tried about everything and am loosing hope for this car. Any help would be appreciated. Thanks

[Dave1027]

What about the water pump? You removed both thermostats? Pressure test the system?

[FREAKx13]

Yes it's all working properly. Water pump isn't missing any fins

[FREAKx13]

And no leaking with the pressure test top hose hot and the thermostat side is warm not hot. Also only half the rad is getting hot

[charter21p5]

Sounds like either bad thermostat or air bubbles.

[MarcoZandrini]

Did you properly bleed the cooling system? See Mango's sticky at E46Fanatics.

[heechkass]

You may have a blocked or partially blocked radiator. You can flush it with a hose to see if you unplug it.

[Flash 330CI]

I just went through this but on purpose. Did you run the Heater wide open while bleeding the system? When everything is cold add more water coolant mix to the overflow tank and top it more than it needs, walk away. Look at it after a couple of hours, you might be surprised. Do all of this while the front end of the car is elevated. After all of this, Use a turkey baster and draw out the excess coolant from the overflow tank (If Any), run the car and bleed it again, run the Heater wide open to 91 degrees you know you have it right when the output hose from the thermostat is very hot and heat is blowing out of the air vents. It is amazing that you can fill the overflow tank to the proper level, run it, everything works normal, bleed it, but then it starts to overheat slowly. I found that the secret is the fact that there is still air in the system! That is why in my experience I purposely overfill the overflow tank and it fills the air void in the engine (Then I Adjust the Coolant Level), It takes it good old time also. LOL Check the coolant the next morning and adjust if necessary.