It sounds like we need to get on the same page as to what (1) diagnostics, and (2) parts replacements have been done in the last month or two, and when, BEFORE you spend more time & money throwing parts at it.
9/12, Post#1:
1) You stated that the car would NOT start, so you replaced the starter & alternator (no identification of any DTCs, whether the original starter cranked the engine but not fire, alternator voltage output, etc.).
2) You stated that AFTER replacing starter & alternator: "I tried starting the car, and it wouldn't turn on." I assume you meant the starter cranked the engine, but the engine did NOT fire?
3) You stated that: "I had to reset the trouble codes in order to start it. It finally turned on, and I thought that was the problem fix, but around 30 minutes after the car was on. It started to overheat."
QUESTIONS:
a) WHAT were the trouble codes you CLEARED?
Hint: ALWAYS record all DTCs and Freeze Frame Data BEFORE clearing codes.
b) WHAT diagnostics did you do to evaluate the coolant pump and/or thermostat? WHO is "everyone" who suggested coolant pump & thermostat? Did you read codes (what coolant pump code was saved in DME Memory?) or do any Activation of the pump (including pressing the accelerator pedal for 10 seconds)? Do you have a scan tool or BMW-specific software, and if so, what model?
4) You stated: "I figured it was the water pump, so... I replaced it with a new one, replaced the thermostat too, like everyone suggested."
5) Then after replacing the pump & thermostat, the pump would NOT run when you tried to bleed the system by pressing the throttle for 10 seconds with ignition on, engine OFF. You checked fuses -- did you record which ones you checked? Did you refer to the proper circuit diagram for the coolant pump on your model in TIS or Bentley (see below)? Do you have a multimeter and know how to read voltage at the pump connector?
9/20, Post#12:
Do I understand correctly that you replaced the coolant pump and thermostat AGAIN (2nd time in a MONTH), AND the pump will NOT run???
I'm sorry you have NOT received proper diagnostic advice in this thread. You say that one of the codes you deleted "to get the car to run", presumably ON or BEFORE 9/12/18, was
2E84. That is a communication fault between the DME and Coolant Pump. It is NOT a Speed Deviation Fault (2E81) which would indicate a failing pump. It would appear that your currently-installed pump (and probably any other pump(s) you have removed since this whole fiasco began) is OK, and you have a power supply fault, ground fault, or other wiring fault.
Here is the TIS circuit diagram for your 330i cooling system. The coolant pump is component#
M6035, on the right side of the schematic:
https://www.newtis.info/tisv2/a/en/e...ooling/i7SHdY5
Note that there are TWO (2) fuses supplying power to the Control and Motor respectively: (1)
F02, 30A, located in the E-box, which powers the control circuit, and should produce 12V+ at pin# 2 (Orange wire) of Connector
X6035 at the pump when Terminal 87 is active; (2)
F09, 30A, also located in the E-box, which provides primary pump power, 12V+ at pin# 1 (Red wire) of Connector X6035. Test for 12V+ at BOTH pins #1 & #2 (Red & Orange wires) with ignition on, being careful NOT to short/ground either pin. There is also a ground at pin# 4 (Brown wire) of Connector X6035 and you should test for continuity to ground at that pin.
Finally, note the DME control of the pump, turning it on, off & regulating speed, including running the pump for bleed procedure, is via the Violet wire, from pin# 26 of Connector
X60007 at the DME to pin# 4 of the pump connector. That is also known as the BSD Bus (Bit-serial Data). Test that wire for continuity, with the connector disconnected from both DME & Pump. The BSD Bus also controls alternator output -- you did NOT state in this thread what caused you to replace the alternator. Does your alternator NOW produce voltage in the 13.5V to 14.5V range with motor running (just run for 30 seconds to test voltage at jumpstart terminal)? Do NOT run engine for more than ~ 1 minute from cold with coolant pump NOT functioning.
The TIS circuit diagram is interactive, and you can click on any
BLUE component ID# and get more information on that component, such as Installation Location or Connector View. Here is the Connector View for
X6035:
https://www.newtis.info/tisv2/a/en/e...i-lim/CTMccBeM
Here is the location for
F02:
https://www.newtis.info/tisv2/a/en/e90-330i-lim/Ri8cSt3
Please let us know what you find,
George