You have a blown head gasket. Go to a parts store and get a radiator stop leak that has copper in it. It is called Liquid Glass and there are several suppliers of it. I have used this in many cars over the years and have had very good success with it. It is about $6. Follow the instructions and let it dry overnight.
AnswerOne potential cause is too much gas. It may be running "rich". Your car may also be burning a little oil. White smoke is usually water or antifreeze. If you are loosing coolant from the radiator, it's probably a blown head gasket. If not, it is just condensation in the exhaust pipe that is evaporating as the pipes heat up. If the car is running too rich, the unburned gas will cause black smoke and burning oil smoke will be blue.
It sounds like you are burning oil. Is it dense, or just a thin cloud. Check your oil level, if it is too high, you can force oil around rings and burn it. The rings on the pistons could also be shot. What year/model/etc. is it? Also, be sure to check your oil every time before mowing, and after for that matter. This will prevent overheating, and also a premature rebuild.
Typical of a Bad Head Gasket
built up heat coming out engine breather tubes on the motor!
if the smoke is white and you've over heated the car in the past there is a good chance that you have blown the head gasket or even the heads sorry
Head gasket is leaking
It's probably a heat shield, to protect the passenger compartment floor or fuel tank (or whatever is near the muffler) from excessive heat from the muffler. You could remove it, but why bother?
Sorry bad news Your heater core has a leak
When gasoline is burned in an engine, it turns into heat, water, and a couple of different carbon compounds. The water, being hot, is in the form of a gas. When it hits the cold exhaust pipe, it condenses back to liquid water.
Confinement and excessive heat Smoke-stained windows Smoke puffing at intervals from the building (appearance of breathing) Pressurized smoke coming from small cracks Little visible flame from the exterior of the building Black smoke becoming dense gray-yellow
That is probably antifreeze steam. Your heater core is a small radiator used to heat your car. The engine heats the antifreeze and circulates it through the heater core. Your blower blows heat through the core (radiator) into the car, and warms you. If the core gets a small leak, it will put out steam.
Check you've got water in the cooling system.