* Blown Head Gasket: This is a very common cause of smoking when hot. A blown head gasket allows coolant to leak into the combustion chamber, where it turns to steam and is expelled as white smoke from the exhaust. You might also notice a loss of coolant, milky oil (oil mixed with coolant), or overheating.
* Cracked Cylinder Head: Similar to a blown head gasket, a crack in the cylinder head allows coolant to leak into the combustion chamber, resulting in white smoke. This is often accompanied by overheating and other signs of coolant loss.
* Burning Oil: Blue or greyish-blue smoke usually indicates burning oil. This could be due to worn piston rings, valve stem seals, or a leaking PCV valve. Oil consumption will likely be increased.
* Leaking Valve Cover Gasket: While less likely to cause significant smoke, a leaking valve cover gasket can allow oil to leak onto hot engine parts, causing some burning and smoke, especially if the leak is significant. This smoke is usually light blue/grey.
* Clogged Catalytic Converter: While not directly causing the smoke, a clogged catalytic converter can cause increased back pressure, leading to increased engine temperatures and potentially exacerbating other issues causing the smoke. This might manifest as reduced engine power alongside the smoke.
To determine the exact cause:
You'll need to have a mechanic inspect the vehicle. They will likely perform a visual inspection looking for leaks, check the oil and coolant levels, and possibly perform a compression test or leak-down test to diagnose problems with the engine's internal components. The color of the smoke (white, blue, grey-black) is a crucial clue, as is the smell.
Don't continue driving the car extensively if it's smoking heavily. This could lead to further engine damage, especially if the problem is a blown head gasket or cracked cylinder head.
