White Smoke On Startup Then Disappears

Car generate white smoke when starting engine.

If you see any sort of smoke coming from your exhaust on startup, whether it’s white smoke, it’s a sign that something is wrong with your car and it needs your attention.

No matter how you detect the white smoke, you must act quickly to stop it from becoming worse. Make an appointment with your technician to prevent any additional engine or exhaust system damage if this happens. While it’s a good idea to entrust the work to the mechanics, we suggest it’s also a good idea to know what triggers the white smoke in the first place.

In this article, we will explain what white smoke is and how to deal with it. We will also clarify any concerns you may have about this issue.

Causes of Car Blowing White Smoke from Exhaust

Coolant Leak

Your external coolant may be leaking if you continue to notice white smoke coming out of the exhaust pipe after the engine has had a chance to warm up or when driving at high speed.

Probably the most apparent sign of internal coolant leakage is when white smoke begins to billow from the exhaust pipe, leaving a pleasant sweet-smelling odor in the air. Any time you see or smell white smoke coming from your exhaust pipe, you know your coolant is starting to leak.

A fracture in the cylinder head or engine block is typically the source of coolant leakage. Although whether the crack is just a few millimeters wide, the internal coolant may quickly seep out and pollute the engine’s oil. Ultimately, this culminates in a cloud of whitish exhaust smoke.

A whitish color in the smoke will be caused by the mixture of coolant and engine oil. If even a little amount of coolant enters the combustion chamber, white smoke will begin to emanate.

Having a low coolant level combined with an unmaintained cooling system can cause your engine to overheat and eventually malfunction. Once your head gaskets become too hot, they can’t properly seal, and it will lead to failure. Consequently, your engine and internal components will wear out and break down considerably more quickly, resulting in costly repairs.

Bad Fuel Injector

Over fueling occurs when a fuel injector malfunctions, such as one that is jammed open or has o-ring leakage. Due to the inability of the excessive fuel to be adequately burned in the engine, it manifests as a cloud of white or gray exhaust smoke.

You may resolve the problem by replacing the faulty injector or its o-ring. Due to the difficulty in determining which fuel injector is faulty, many technicians may suggest replacing all of them depending on the vehicle’s mileage. It’s because fuel injectors are not prohibitively costly in most instances.

The injector pump of a diesel engine must operate with pinpoint accuracy in terms of timing and fuel pressure. Due to lack of proper timing, your machine will be running high, leading to fuel not being burned and releasing the exhaust as whitish smoke.

Excess fuel in the Combustion Chamber

In most cases, an overload of fuel in the combustion chamber is caused by a faulty fuel injector. Any kind of fault may be the cause of the issue. You may have an injector jammed open, allowing fuel to be continually injected. Another possibility is that the injector’s O-ring is defective and not working right.

When too much fuel is injected into the engine, it gets overloaded and cannot burn all the fuel. When the engine is starting up, a thick white substance is emitted that contains unburned fuel. Replacing your fuel injector can solve this issue quickly and cost-effectively.

Water Contamination of Fuel

The combination of water and fuel is one of the most common sources of white smoke in cars. It may also happen for a variety of reasons.

One possible possibility is that the gasoline you purchased was of low standard and had been diluted with water from the outset. It might cause by water condensation in the combustion chamber.

When water vapors react with combustion gases in the cold season, they form white smoke, similar to liquefaction. It would help if you were addressed it since the Condition cannot stay in this sense.

It’s not difficult to resolve this issue without the assistance of a professional. It is just a matter of lowering the air pressure in the engine to prevent liquefaction from occurring. However, if there is any water in the fuel, it must be drained.

These are the potential causes of white smoke, as well as their respective treatments. It is a past time for us to figure out what preventative steps should be implemented to avert these issues in the first place.

White Smoke from Exhaust on Startup: What to Look For?

Some factors must be kept in mind to detect whether white smoke signals a potential threat. To begin, let’s talk about the parameters in which there shouldn’t be an issue.

Observing the Smoke’s Thickness

The thickness of smoke is directly proportional to its hazard level. There is nothing to be concerned about if you see just a few extremely thin vapors escaping from the exhaust pipe.

White Smoke During Winters

It’s not uncommon to see white exhaust smoke from the exhaust throughout the winter. It’s because of condensation, a well-known natural phenomenon. Whenever you start on your vehicle during winter, the water vapors begin to evaporate because of the drastic warmth temperature, which absorbs heat and creates puffs of smoke in the process. 

The presence of white smoke from the exhaust on startup must be considered an issue. It is one of the reasons behind parameters that white smoke may be hazardous and the indication of potential sources.

White Smoke Due To Transmission Fluid

A faulty engine forces the vacuum pipe to absorb more fluid, causing the car to overheat. As a consequence, the oil-producing white smoke becomes contaminated. Several further changes occur as a direct result of fluid transmission. 

For instance, it will have a smell like a burning oil odor. For the health of your engine, you must be on the lookout for these warning signals and take immediate action when you notice them. Changing the vacuum modulator valve solves the issue. You need to refill the rest for those who have a lower than the standard transmission fluid level.

A Cracked Cylinder Head

A fracture in the cylinder head is a common source of whitish smoke coming from exhaust on startup. Cracks in the cylinder head may cause coolant to leak into the other cylinders or perhaps even into the combustion chamber in some instances.

When the engine gets too hot, cracks appear. Various factors may contribute to overheating, including a poorly maintained cooling system, a cooling fan that isn’t functioning correctly, and contaminants in the cooling fluid.

What Mechanical Parts You Should Check?

There are mechanical parts of your car that you should inspect to discover why your exhaust is spewing white smoke. Both are related to the engine’s coolant, but one is specifically related to the head gasket. To resolve the white smoke problem, you’ll have to follow a process that includes many stages.

Check the Condition of the Head Gasket

Head gaskets are the next thing to check for once the intake gasket has been inspected. The purpose of this is to seal the head to the block using this gasket. Its primary priority is to keep coolant free from leakage. There should be no delay in fixing a faulty head gasket.

Conduct a Coolant Level Monitoring

To begin, remove your car’s hood and check the coolant levels. Nevertheless, bear in mind that before removing the radiator cap or reservoir cap, make sure the engine is cool. You should wait about 30 minutes after starting the engine to inspect the coolant level if it’s still hot from running. 

Check Coolant Reservoir

To determine whether or not a low coolant level is causing your white smoke, check your engine once it has cooled down completely. The coolant may be checked by looking into the coolant chamber or inserting a stick into the reservoir and measuring the remaining coolant. However, the stick will tell you exactly how much coolant is remaining in your vehicle, which is more precise than just peering into the coolant chamber.

Other Parts of the Engine Should Be Inspected

If the coolant level is sufficient, the next step is to inspect the cylinder head, head gasket, and even the engine block itself for any signs of cracking or other damage that may cause the coolant to blend with the oil or fuel. If so, replace them. Additionally, if feasible, you should run a cooling system pressure inspection to pinpoint which component is causing these problems.


It all depends on what color and kind of smoke are spewing to determine how bad things will get. White smoke from the exhaust is typically caused by condensation that has built up in it. The smoke emitted will not directly affect you, but it is imperative to know the cause and why you may notice white smoke from exhaust on startup. Smoking is not restricted to startup, and you may also see white smoke coming from the exhaust while driving or when the vehicle is at rest or idling.