Ran AC in heavy traffic; car sputtered and then wouldn't start

[Maggiolone]

I was in heavy traffic with a load of passengers and luggage in my 325e. The car began to sputter and shake; the oil warning light would flicker and the temp gauge creeped slowly to the red.

We got to our destination without over-heating. I attempted to start the car a minute later, and I received NOTHING when I turned the key. I initially thought it was a dead battery.

3 hours later, the car started and ran fine - without the AC on, too.

I don't know. ICM? ICV? Or, new battery needed?

[getouth]

sounds like an electrical relay issue ....... gets too hot and doesn't work right, cools off and is GTG.

[Das Delfin]

CPS possibly.. it's not unheard of

check your oil first

[mazzo]

Any check engine light on?

[george graves]

My guess - it's unrelated to the AC in traffic (and who in the world still has AC in their e30?!?!?!? - ok, that's not far, if live in a hot part of the country, I would love AC

Check the voltage while the engine is off, and then when running.

Engine off should be ~12 volts
Engine running should be above 13 volt

[Maggiolone]

I took it upon myself to get a new coolant temp sensor and thermostat. Those helped a bit.

I can safely drive with myself and the AC on. I had passengers again, and my shotgun passenger put the blower motor up to the highest setting. The car stalled. I immediately restarted it, with the fan low.

I'm going to buy a new battery today. The alternator is newer.

[DesertBMW]

the temp gauge creeped slowly to the red.

We got to our destination without over-heating. I attempted to start the car a minute later, and I received NOTHING when I turned the key.

Engine overheated so much that pistons expanded and were locking up against the block. After you shut it off, there was too much friction for starter to move the pistons. But when engine cooled off, pistons shrank and you were able to start it again. Cylinder walls are scratched now.