White Smoke From Tailpipe When Starting Car? (Main Causes)

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Under normal conditions, the gas coming out of your exhaust tailpipe would be almost invisible. But then, in some cases, the exhaust fumes may be light white depending on how gas was burnt in the combustion chamber.

The truth of the matter is that the color of the fumes coming out from the exhaust tailpipe of your car tells so much about the condition of your car’s emission system. If you notice a thick white smoke from tailpipe when starting car, it signifies that water found its way into the combustion chamber.

It could be the coolant liquid or normal water (probably when you washed the engine bay) that got into the chamber and blend with the air-fuel mixture process that goes on in the combustion chamber.

Hereunder is the explanation of what happened.

White Smoke From Tailpipe When Starting Car?

When you start a car, there are pretty many activities that occur sequentially and simultaneously too. On cool days, it’s quite normal to see white smoke come out of the exhaust tailpipe when you start the car; the white smoke would dissipate into almost-invisible exhaust steams after the car warms up.

The white smoke on cooler days (maybe during the winter season) is a result of condensation. However, if you still see white smoke coming out of your car after it has warmed up, that is a sign that water is penetrating the exhaust system. Yes, the major cause of white exhaust smoke is “leaks.”

As said earlier, the nature and color of the steam/fume coming out from your car exhaust’s tailpipe has so much to tell about the current condition of your engine and exhaust system component.

The major exhaust system components are the muffler, resomer, and catalytic converter; if any of this is clogged, you may see white fumes.

Causes of White Exhaust Smokes

White Smoke From Tailpipe When Starting Car

Coolant leak – this is the main culprit here. If you regularly see thick white smoke coming out from your exhaust, it is possible that the head gasket is blown and the coolant liquid is leaking into chambers it is not supposed to penetrate.

Also, a crack in the engine block can allow fluid to travel into the combustion chamber, and the result could be thick white fumes gushing out of the tailpipe.

A cracked head gasket would cause the coolant liquid to evaporate quickly when the car heats up, and when the coolant liquid is down – below the recommended level, the engine is most likely going to overheat, and if this is allowed to go on for a while, you may be needing a full engine replacement service.

What To Do About White Smokes From Exhaust Pipe

You need to have the car checked for cracks and leaks; the head gasket, cylinder head, and engine blocks should be checked for cracks.

Once you detect the exact component that cracked, you need to have it replaced or repaired as early as you can, before the issue skyrockets into a costlier one.


If you regularly see white smoke from tailpipe when starting car, you need to check for cracks and also ensure your coolant liquid is not leaking. Leaks and cracks would allow water and fluids to get into areas they are not meant to penetrate, and once this happens, you’d start experiencing issues while driving.

However, while we mentioned leaks as one of the things to check when you see thick white exhaust fumes, it is important to note that oil leaks don’t cause “white smoke.”

If oil finds its way into the exhaust system, what you’d see is blue-tinted fumes/smoke, not white. Either way, always ensure that nothing is leaking or cracked in the engine bay.

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