What does it mean when a car lets out white smoke? I have a 98 BMW Z3 1.9 L?

did the white smoke come out the tailpipe? and did it pour white smoke on the way home??? and how did it drive on the way home. It is going to need a good mechanic, and its best to tell him what happened and what you did.

never take off the rad cap when the engine is warm, the anti freeze will come out. could be a head gasket, but i think you would have been pouring white smoke out of the tail pipe if it were. might be a belt burning up or fan motor, hence the burning smell.

car 253 is using the simplistic..white smoke = head gasket...but before you spend 1500 to 2000 on rebuilt head and gaskets 1 thermostat sticking 2 AC clutch bad and burning or burning "fan" belt start with simple things working toward the worst ie head gasket

I would suspect that your oil pump needs replacing. I would say that your engine bearings were deprived of lubrication for a while which would cause the piston rings to overheat and allow exhaust smoke out of the tail pipe. The burning smell would be due to the piston rings ovrheating. A simple test for a blown head gasket, is to go to a garage and ask for a compression test. They remove the spark plugs and test the compression on each cylinder, if the test shows any low compression, then you need a new head gasket. It is not an expensive test, it takes about 20/30 minutes.

Not very good condition, I would say. Clean, maybe. But obviously someone forgo taking the car in for regularily scheduled maintenance. And it is 10 years old. So there could be a lot of maintenance. Such as hoses replacement, belts replacement, etc. This car needs a mechanic to "look it over" (not just neighbors opinions). You don't go to the neighbors if you need "brain surgery". Same for the car. It has to see a "car doctor" yesterday. So find a trusted mechanic(does not have to be BMW dealership as they are mainly focused on selling cars - but then again maybe the dealership could direct you to knowledgeable BMW mechanics. As it came from under the hood, it could be a broken hose(with a pinhole leak) and the white you saw is steam. Or electrical, and the smoke you saw was wiring covering burning off. Fan belt might be another problem that smokes. Again for a experienced mechanic, we know what smells like what. Why you were losing power is a ??? Again, not something done over the net. Engines are all the same as to their headaches. Oh, and as for removing the rad cap on a hot motor.....NEVER DO THAT. Leave it on. You want all the coolant to remain in the engine, otherwise you will warp the cylinder head. (then the cost is the cost of a new head $1000 minimum.) which was totally unnecessary. When in doubt, call a Tow truck. That is what they are for.

Here is my remote diagnosis. You A/C clutch froze up and stopped being able to turn. This caused the serpentine belt to get hot and start burning the rubber it's made of. Because the A/C clutch assembly MUST be able to turn with the other engine components, like water pump and alternator, and power steering. This is NOT a horrible problem. It should be easy to see if the A/C clutch will turn by hand. If not, you will need a rebuilt A/C pump (with new clutch). BE SURE that you use ONLY GENUINE BMW COOLANT in this car. If you added ANYTHING else to it, GET IT OUT OF THERE AT ONCE!!!! You WILL develop an expensive problem on down the road as your cooling system deteriorates. The burning smell was most likely the rubber in the serpentine belt. GET a new belt!! Make sure that your electric cooling fan can be turned by hand (with the engine cool, of course) Luckily for you, I do NOT predict a major engine fault. GOOD LUCK!!

Sounds like a blown head gasket to me. Time to get another car. Tell that guy that sold you the car that you want your money back. When the car is absolute cold take off the oil cap (where you put the oil in) and look at what color the cap is. If the cap is a gray color you probly have a blown head gasket. The car not accelerating means the engine is gone. If a car overheated you could have blown the head gasket or the prior owner did and sold you a bad lemon car.