7 Major Causes of White Smoke From Exhaust on Startup, When You Are Accelerating And Idle

When you start noticing white smoke from the exhaust, either accelerating or when idle, then it can be a clear indication that your vehicle may have an issue that needs your attention. Its seriousness entirely depends on the type and color of smoke that comes out. In most cases, the white smoke from exhaust on startup is because of the condensation that accumulates within the exhaust.

It is worth mentioning that such kind of smoke may not be having a direct impact, but you need to understand what it means and the reason for the white smoke from exhaust on startup. There is a possibility that it might not only be limited to the startups, but white smoke from the exhaust can be seen when you accelerate, and you may also see it from the exhaust when the engine is idle.

What are the main reasons for white smoke from exhaust on startup?

  • A cracked cylinder head


You will see the coolant leaking out when you have a damaged or cracked cylinder head. Although the crack doesn't need to be that big, even a tiny gap might be enough to leak the coolant and get mixed. Therefore, the oil may get contaminated because of this.

What Can Cause A Cylinder Head's Crack?


Cracks in cylinder heads can occur for a number of reasons. The most common cause is due to extended periods of high engine temperatures. This can happen when the vehicle is driven hard for long periods of time, or if the cooling system is not working properly. Other causes include physical damage (such as from a rock hitting the head), or manufacturing defects.

How to fix a cracked cylinder head?

If you have a cracked cylinder head, it is important to get it repaired as soon as possible. A cracked cylinder head can cause your engine to overheat and can lead to serious engine damage. There are several ways to repair a cracked cylinder head, but the most common and effective way is to weld the crack shut.

If you decide to weld the crack shut, it is important to use a welding rod that is made of the same material as the cylinder head. This will ensure that the weld will be strong and will not cause any further damage to the cylinder head. Once the welding is complete, you should have the cylinder head checked for cracks by a qualified mechanic.

If the crack is too large to weld shut, then you may need to replace the cylinder head. This is a more expensive repair, but it will ensure that your engine is in good working order. Be sure to have the replacement cylinder head checked for cracks before you install it.

No matter what method you use to repair your cracked cylinder head, it is important to have the repairs done as soon as possible. A cracked cylinder head can cause serious engine damage if it is not repaired in a timely manner.

  • Condensation burn off


When white smoke comes directly from the muffler, you should never assume it to be the worst. Try not to worry about it because it can just be condensation accumulation. In this situation, the white smoke can be seen on cooler days and comes out in small amounts when the engine is started.

What Can cause the Condensation to burn off in your car?

There are a few things that can potentially cause the condensation to burn off in your car. One possibility is that your car's cooling system is not functioning properly, and the coolant is boiling off instead of evaporating. This can happen if there is a leak in the system, or if the coolant level is too low. Another possibility is that the temperature inside your car is set too high, causing the moisture in the air to condense and then evaporate. Finally, it's also possible that you have a clogged air filter, which is not allowing enough ventilation and causes the condensation to build up. If you're not sure what's causing the condensation to burn off in your car, and, as a result, you don't know what causes white smoke from exhaust on startup, it's best to take it to a mechanic and have them diagnose the problem.

  • Damage in the coolant reservoir tank


Another excellent reason for the white smoke from exhaust on startup can be the reservoir tank of your coolant. Generally, it may not leak, but it occurs if the tank gets harmed or broken. There are times when it happens when the mechanic fixes another issue and damages the tank accidentally.

What can cause damage to the coolant reservoir tank?

There are several potential causes of damage to the coolant reservoir tank. One possibility is that the cap on the tank is not properly secured, causing pressure to build up and eventually causing the tank to burst. Another possibility is that there is a crack or hole in the tank itself, which can allow coolant to leak out and cause damage to surrounding components. Finally, if the tank is not properly maintained and cleaned, it can become corroded and weakened over time, making it more susceptible to damage.

How to fix the damage in the coolant reservoir tank?

If the damage to the coolant reservoir tank is minor, it may be possible to repair it. However, if the damage is significant, it is likely that the tank will need to be replaced. In either case, it is important to consult with a qualified mechanic or technician to ensure that the repair or replacement is done properly and that there are no underlying issues that could cause further damage.

  • Oil leakage


If the oil starts to leak out of the valve seals or the piston rings, it may float into the inner combustion compartment and the fuel, and produce white smoke from the exhaust on startup. When the mixing of the oil and fuel happens, then they can come out of the tailpipe. Here, you will see blue smoke from the exhaust that may appear white to some.

How to fix the oil leakage?


It is advisable to take your car to a mechanic and have it checked as soon as you notice any oil leakage. Depending on the severity, the mechanic will either change the seals or gaskets or replace the entire oil pan. In some cases, they may also suggest replacing the engine oil. You should always follow their advice to avoid any further damage to your car.

How to prevent oil leakage?

1. Inspect your engine regularly. Look for oil leaks around the seals and gaskets.

2. Replace any damaged or worn seal or gasket.

3. Use a higher quality oil if you notice that your engine is leaking oil.

4. If you continue to have oil leaks, take your car to a mechanic for further diagnosis and repair.

5. Check your oil level regularly and top off as needed to prevent engine damage from low oil levels.

  • Poor fuel injector


This is quite an important component liable for infiltrating the fuel into the inner combustion chamber. If you don't have a good fuel injector, then there are chances that it may form the white smoke from the exhaust on startup. The main reason is that the correct quantity of fuel may not penetrate the compartment at the right time.

Major Signs Of Poor Fuel Injectors

Clogged or dirty fuel injectors are one of the most common signs of poor fuel injectors. If your fuel injectors are not working properly, it can cause your engine to run lean or rich. Lean means there is not enough fuel being delivered to the engine and rich means too much fuel is being delivered.

Another sign of poor fuel injectors is misfiring. Misfiring can be caused by a number of things, but one of the most common causes is a dirty or clogged fuel injector. If your engine is misfiring, it can cause knocking, pinging, or other strange noises.

If your vehicle is hard to start, if it stalls often, or if you see white smoke from the exhaust on startup, this can also be a sign of a poor fuel injector. If your vehicle is running rough, or if the idle is erratic, these are also signs that your fuel injector may need to be cleaned or replaced.

How To Fix Poor Fuel Injector?

One of the most common issues that can occur with fuel injectors is poor performance due to clogging. When this happens, it's important to clean the injectors as soon as possible to prevent any further damage. There are a few different ways that you can clean fuel injectors, but one of the most effective methods is to use a professional injector cleaning service. This type of service will clean the injectors and remove any build-up that may be causing the clogging.

Another issue that can cause poor fuel injector performance is a faulty or damaged injector. In some cases, it may be necessary to replace the entire injector. However, if the problem is only with one or two injectors, it may be possible to repair them. In either case, it's important to take the vehicle to a qualified mechanic who can properly diagnose the problem and recommend the best course of action.

Fuel injector problems can be frustrating, but they don't have to be. With a little knowledge and the right tools, you can fix the problem quickly and get back on the road.

  • Error in the engine control unit


If your engine control unit is faulty or glitchy, then there are chances that it may disturb the fuel injector timing. Although it may not mean that your fuel injector is wrong, you should reprogram the engine control unit for accurate fuel injector timing.

How To Fix Error In The Engine Control Unit?

There are several ways to fix an error in the engine control unit. One way is to use a software program that can re-program the engine control unit. This will require getting a new software program and downloading it onto your computer.


Another way to fix an error in the engine control unit is to physically replace the unit. This will require taking the old unit out and replacing it with a new one. If you are not comfortable doing this, you can take your car to a mechanic and have them do it for you. Finally, you can send the engine control unit back to the manufacturer to be repaired or replaced. This may be the best option if the unit is still under warranty. Whichever way you choose to fix an error in the engine control unit, be sure to follow the instructions carefully to avoid damaging the unit or your car.

  • A cracked engine block


When your whole engine block has a rupture in it, this might be the worst-case scenario for you. Such a problem can be very costly to fix, and you may not know which issue is the actual cause of the white smoke produced. You will know it when you visit the mechanic and have a diagnosis performed on it.

Final Thoughts

When you start noticing some white smoke from the exhaust on startup, this might be because of the internal issues of the engine. By having fixed the white smoke billowing from the exhaust, you can prevent any future fuel issues, including engine repairs, problems with the fuel injection system, and any transmission issues that can build up from the unburnt fuel.