What happened in my engine?

[Bimmer Nut Ed]

OK, the strangest thing just happened to my 1999 Z3 M52 i6. After driving it and turning it off, then trying to start it 10 minutes later, it would not start. It tried, the starter motor engaged, turned the engine over only a hair where you could just see the the fan blade move maybe an inch.

OK, I towed the car home, assumed it was the starter motor, replaced the starter motor. BTW, a real pita in a 6 cyl z3.

Still no start, still same symptoms.

I charge the battery overnight, try in morning, hear a pop, then the car starts up. Now white smoke, big time. That's all I have now, it ran well, while a ran it, but it's burning coolant.

Could the water pump somehow locked up, now somehow throwing coolant into the intake. Does not make sense. Any Ideas?

[Ross]

Just saw this same scenario, it was a head gasket.
After shutdown the pressure in the cooling system forces coolant into the effected cylinder hydro-locking it.
Did it run ragged when it started?? That's the coolant burning off.
Hope I'm wrong.

[whiskychaser]

Any black stuff in the expansion tank? I'd be taking out the plugs to see if any are wet. I've had one motor drop so much coolant into the cylinders it wouldnt turn over. Spun it with the plugs out and water spurted out of the plug holes. HG was shot. Sincerely hope this is not the case.

[ryan roopnarine]

IIRC, i don't believe that the intake on your iteration of the bmw I6 has any reason to have coolant passages that run through the intake. good luck, in any event.

[Bimmer Nut Ed]

Yeah, I'm thinking head gasket, and hydro-lock causing the no start symptom. I'll go pull the plugs and let you all know. Good call.

Yay, I get to do a head gasket. Have not done one on a bimmer yet.

Wonder if my daughter who was driving it at the time noticed anything like overheating or such.

Thanks guys.

[Ross]

"Wonder if my daughter who was driving it at the time noticed anything like overheating or such."

Ha!

[Bimmer Nut Ed]

She's usually pretty good about these kinda things, you forget, she has me for a daddy. I'll have to interrogate her when she gets home!

[whiskychaser]

Lets be really cheerful : isnt it more likely the HG went because it overheated and not the other way round? If its gone I'd be looking for the cause: coolant leak, duff pump, stat stuck etc. Then the buttock clenching moment: you have backed off the head bolts and hope that they hold when you do the re-torque test. And if not you are looking for these: http://www.timesert.com/
Fingers crossed.

[Tiger]

Do a coolant system pressure test.

[bsell]

So OP, what did the combustion chamber spies look like?

Spark plugs, that is.

I figure you will find one very clean spark plug of the six...