Why My Car Hood Smoking In Cold Weather?

White smoke is most prevalent when the weather is cold or frosty. Condensing steam causes the white smoke when you first start the car. The white smoke will dissipate or disappear as the engine warms up in normal conditions.

Imagine seeing your car hood smoking in cold weather, it definitely will make you anxious. What if the car engine will blow up? Don’t worry this is completely normal and does not indicate that the vehicle has a problem. Here are some reasons why it happens and a guide to solving the same:

What Causes Smoke From A Car Engine?

Seeing any type of smoke emerge from beneath the hood can be a frightening sight. Most motorists automatically associate car engine smoke with a serious and significant repair, and they begin to worry about the impending cost of repairing the problem; however, before you panic, you should know that your car engine could be smoking for a variety of reasons.

A glimpse of white smoke can appear during a cold start for many of you, whether you’re driving a new or older vehicle. White smoke is more prevalent when the weather is cold or frosty. After the first start, white smoke appears due to condensation in the car. Here are the most common causes of your car engine smoking to give you some relief and help you decide whether it’s time to buy a new car or if it’s just a simple repair.

1. Leaking Coolant

A leak in the coolant overflow tank can result in the steam coming from beneath the hood on occasion. Smoke puffs can also be the result of leaking and burning power steering or transmission fluid. In that case, a cloud of smoke will appear, along with a faint chemical odor.

2. A Blown Head Gasket

A high-pressure gasket will seep through the cylinders and into the coolant, depleting it. The gasoline and air will react to the ammonia once the engine is restarted. When this is done, white smoke fills the air.

3. Spilled Oil

The presence of oil outside the engine, where it does not belong, could cause the car to smoke under the hood. If you aren’t careful when filling up the gas tank, oil could end up there. Alternatively, a spill could occur while adding oil to the crankcase.

If it’s just an oil spill in the wrong place, it won’t do much damage other than emitting a strong, oily odor. It will quickly burn off with no long-term consequences. However, if spills occur frequently and you continue to drive without wiping them off, some rubber or plastic parts may break down as a result of being submerged in oil for an extended period.

4. The Cap For Filling Oil

This is a common problem with older engines. Almost all engines emit a faint whiff of smoke from the oil filler cap, which is a residue of the burned fuel inside the engine. Older engines generate more hot spots, causing the car to smoke under the hood but not overheat.

This smoking problem is caused by worn-out piston rings and a clogged PCV tube or valve. The pistons siphon fuel into the cylinder, where it burns and produces smoke, thanks to the worn rings. After that, the smoke passes through the piston rings. The smoke is supposed to be drawn back into the engine by the crankcase ventilation and burned again. When the PCV tube or valve is faulty or blocked, however, this does not happen. The smoke is released through the oil filler cap in this case.

What To Do When Car Hood Smoking In Cold Weather?

If you notice steam or smoke coming from your engine, pull over when it is safe to do so and turn off your engine. If you are comfortable with it, pop the hood of your car. Before you can open the hood, the engine must be cooled. You will only do this if you are certain that it is safe to do so.

1. Checking Coolant Level

In cold weather conditions, hood smoke is mostly caused by leaking coolant. Check your car’s coolant level on a weekly or bi-monthly basis. Coolant damage or seeping can be indicated by a steady drop in the level.

2. Check The Temperature Gauge

Is your vehicle’s engine overheating? If that’s the case, the first thing you should do is open all of the windows and turn on the heater in your car. This assists in removing some of the heat from your engine until you can find a safe place to pull over. Pull over and turn off your engine once you’ve found a safe location.

3. Repair The Thermostat

If you see your car thermostat surface is blocked by any rust, corrosion, or any other reason, immediately repair or replace it as a defective thermostat can cause smoking in the hood.

4. Fixing Cracked Engine Block

If the cooling system is filled with too much water and not enough antifreeze, the block can crack in freezing temperatures. It usually gets repaired by welding but sometimes the mechanic will recommend you to replace it which can cost you a lot of money.


Frequently Asked Questions:

Here are some frequently asked questions about car hood smoking in cold weather:

1. What Is The Source Of The Steam Coming From Under The Hood?

A loss of coolant through a ruptured hose, a punctured radiator, a defective thermostat, a defective radiator cooling fan, or a blown cylinder head gasket are all possible causes of overheating

2. Is White Smoke Always Related To A Blown Head Gasket?

White smoke cannot always be attributed to a blown gasket, but it is the most common cause of white smoke.

3. Why Does A Car Produce Smoke Only When It Starts In Cold Weather And Not When It Is Hot?

When it’s cold outside, you can see more water vapor in the exhaust. It’s also worth noting that the engine control computer runs the engine in “open-loop” mode when the car starts. This indicates that the fuel-air mixture has been set to a preset value that causes the engine to run rich. The computer switches to “closed-loop” control mode after the catalytic converter and O2 sensors have warmed up and optimizes the fuel-air mixture to the exact stoichiometric ratio required for complete combustion. There is a noticeable reduction in visible exhaust at that point.

4. Is It A Cause For Concern If My Hood Is Smoking?

If you see smoke coming from beneath your hood while driving, pull over as soon as it is safe. Turn off the engine and lift the hood to inspect what’s wrong and determine whether it’s safe to drive to a repair shop or if a tow truck is required.


If you see your car hood smoking in cold weather while driving, pull over as soon as it is safe. Turn off the engine and lift the hood to inspect what’s wrong and determine whether it’s safe to drive to a repair shop or if a tow truck is required.

If you notice white smoke in the air, it’s most likely due to your car’s coolant fluids. On extremely cold days, you may notice white smoke coming from beneath the hood of the car sometimes this is normal and does not indicate that there is a problem with the vehicle. But it can also be some of the other issues. With the help of the points mentioned above, you can easily diagnose if there is a problem with your car engine. If that doesn’t work try consulting a skilled professional to solve the issue.

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