Over heating, changed water pump, heater intake elbows, and thermostat, ran fine for a few days then stalled again. Smoke out of the exhaust and engine. Blown head gasket or UIM/LIM is my guess, but how can I be sure? And any help on how to fix it would be greatly appreciated!

SOURCE: black smoke from exhaust

hi nishga
im dave; hope i can help

First you need to determine if it is actually black smoke or if it is blue smoke. There are three colors of smoke that can come from the tailpipe. It is not white smoke obviously because that is easily differentiated from blue or black and generally indicates water or antifreeze leaking past the head gasket and into the compression area of the motor. White smoke is the steam of the water/antifreeze being emitted

Blue smoke is caused by engine oil entering the cylinder area and being burned along with the fuel air mixture. As with white smoke, just a small drop of oil leaking into the cylinder can produce blue smoke out the tailpipe. Blue smoke is more likely in older or higher mileage vehicles than newer cars with fewer miles. The car has many seals, gaskets, and o-rings that are designed to keep the engine oil from entering the cylinder, and one of them has failed. If too much oil leaks into the cylinder and fouls the spark plugs, it will cause a misfire(engine miss) in that cylinder, and the spark plug will have to be replaced or cleaned of the oil. Using thicker weight engine oil or an oil additive designed to reduce oil leaks might help reduce the amount of oil leaking into the cylinder.

Black smoke is caused by excess fuel that has entered the cylinder area and cannot be completely burned. Another term for excess fuel is "running rich". Poor fuel mileage is also a common complaint when black smoke comes out of the tailpipe. Black smoke out the tailpipe is the least cause for alarm. Excess fuel will usually effect engine performance, reduce fuel economy, and produce a heavy fuel odour in the engine compartment. Some of the causes of excess fuel are a carburetor that is out of adjustment which is not likely unless you have installed an aftermarket carburated system on your non-carburated car, a faulty fuel pump, a leaky fuel injector, or a faulty engine computer or emissions sensor. If black smoke is present, check the engine oil to make sure excess fuel has not contaminated it. Do not start the engine if a heavy, raw fuel smell can be detected in the engine oil. Check the above mentioned systems and after detecting the trouble replace the faulty parts and then the engine oil and filter.

SOURCE: '94 grand am cooling system failure

What engine do you have? One noted problem with the 4 cylinder engines is the reliability that at some point the intake will crack. I went through all the same things when I bought my 93. Drove off the lot, started overheating, replaced the thermostat and still had the problem without moving from the driveway. Look all around the intake. Make sure car is full of coolant and have the engine running. Most likely you will see a small coolant leak on the backside by the firewall. These cars were known for this problem. By the way if this is the problem make sure you take it to a reputable mechanic, make sure you get a new one installed. I had a used one and had the car back in the shop the next day. It then sat there for 2 more weeks while the used car dealer and I had a "discussion".

SOURCE: water and white smoke comming out exhaust

your cooling system is preasureising due to a leaking cylinder head gasket the white smoke you see is coolant passing through the exhaust valve on the offending cylinder have the cooling system tested for CO content hope this advice helps

SOURCE: 2000 Sunfire coolant problem. Engine overheating,

ok, its time for a radiator flush. there is major sludge in the internals of this radiator. Make sure the thermostat is in the correct position as well. I've seen many cars come into my shop with the thermostat inserted backwards.

SOURCE: Intermittent white smoke out exhaust and engine misfire

The piston rings in your engine might be needed to be replaced already... go to a local shop with a compression tester.. have your engine tested for compression leaks.. if it does have compression leaks.. then you need to change piston rings. Note** white smokes = engine is burning oil..