White Smoke from Under the Hood: Common Causes

Learn the most common causes of white smoke from the under the hood

If you notice white smoke from under the hood, pull over immediately and shut off your engine. Check your engine temperature gauge to see if the engine has overheated. An overheated engine can cause a radiator hose to burst and blow the coolant out of the engine. In that case, the smoke would look like white steam and have a sweet smell. any grease or oil on the engine to burn off and cause smoking from under the hood.

However, other causes can result in a medium gray-to-black color smoke. Let’s take a look at the most common causes and how they appear.

A cooling system leak is the most common cause of white smoke from under the hood

The white smoke is steam from evaporating coolant. A cooling system failure can be caused by:

• A burst radiator or heater hose
• A burst radiator
• A leaking water pump
• A failed water pump drive belt

Symptoms: White smoke from under the hood. The engine temperature gauge is in the “hot” zone.

What to do. Call a tow truck and have it brought to a shop. Do NOT continue driving. Driving with a cooling system failure can destroy your engine, costing upwards of $5,000.

An oil leak is the 2nd most common cause of smoke coming from under the hood

Smoke from an oil leak is often a bit darker in color than a cooling system leak, but in small amounts it can appear white.

1) Motor Oil leak from valve cover gasket failure— Valve cover gaskets leak as they age, and oil drips down the side of the engine. The oil burns on the hot exhaust, causing smoke to come from under the hood. Check for leaking oil dripping down the side of the engine.

2)Power steering fluid leak from power steering hose— A leak in a power steering fluid line can also cause a car smoking from under the hood condition. This happens when the fluid lands on hot engine parts and burns. Check your power steering fluid level.

A head gasket failure can cause white smoke from under the hood

Head gaskets can fail in several ways. If the gasket fails between the cylinder and a cooling passage, the engine can pump hot exhaust gasses into the cooling system. In that case, the gasses can push coolant out of the coolant reservoir, causing white smoke from under the hood. The smoke would appear as thick white steam

Belt failure causes smoke coming from the engine bay, along with a burnt rubber smell

Belt failure that causes smoke is caused by a seized pulley. The belt burns up as it skids across the seized pulley. This would also cause a loud, screeching sound. The smoke from a burned belt appears dark grey.

©, 2020 Rick Muscoplat