It’s not unusual to see different types of smoke coming out of your car’s tailpipe. Smokes range from Blue, Grey, Black, and White with each pointing to a particular problem in your vehicle. One common situation you’re likely to find yourself in is white smoke on startup then disappears.
Sometimes, white smoke can be common and harmless and other times, it can point to a serious situation in your vehicle that needs immediate attention. Now, one of the major causes of white smoke in the exhaust is the accumulation of condensation in the exhaust system. Although this is a common phenomenon, there are other causes that reveal similar symptoms.
If this is what you’re experiencing, then it’s important that you take your vehicle to a repair shop for further inspection. Though a professional mechanic will handle the situation, it doesn’t hurt to get some general information on what could have caused the white smoke. So, in this guide, we’ll discuss what exactly causes white smoke on startup and then detail some steps you can follow to remedy the situation.
But First, What Do the Different Smoke Colors Mean?
Unless you’re driving an electric or a hydrogen-powered vehicle, any other type of engine will emit white smoke at a point. You see, gas and diesel engines operate via internal combustion, which produces exhaust emissions when the vehicle is idle or when it’s accelerated.
Now, in this guide, we’ll discuss white smoke in particular. But, other than white smoke, there are other types of smoke you’re likely to see from time to time which are blue, black, and grey smoke. So, in this section, we’ll discuss what each smoke means to understand what your vehicle is trying to say.
- Black Smoke: If black smoke is what you’re seeing, then this is a clear sign that your car is burning too much fuel. In most cases, this issue is caused by a clogged air filter, blocked manifold, or a malfunctioning fuel injection system.
- Blue/Gray Smoke: In case you’re seeing blue smoke coming out of the exhaust, then it simply means two things.
One, if your car was serviced recently, then there’s a possibility of too much oil in the system or some oil has spilled on the hot exhaust pipe and is being burnt.
Two, if your car has not been serviced recently, then the blue smoke can signal a possible oil leak in the engine. In most cases, this can be caused by several issues such as leaking valve seals, worn-out cylinder walls, or damaged piston rings. In case you’re driving a turbocharged vehicle, blue smoke can be a sign of a worn-out turbocharger.
- White Smoke: This is the most common type of exhaust smoke you’re likely to see when driving. In most cases, white smoke appears in the morning when the engine is at idle and is mostly caused by condensation, which turns into steam when temperatures within the engine rise.
Although white smoke is normal, there are times when it becomes a concern. For instance, if the smoke becomes thicker and doesn’t stop, then there’s a possibility of a more severe issue within the engine. So, some of these possible reasons are exactly what we’ll be discussing in this guide.
What are the Causes of White Smoke from Exhaust?
The first cause of white smoke in the exhaust is the buildup of condensation within the exhaust. In most cases, this issue occurs in cold regions or during winter where exhaust gases condense as they approach the tip of the exhaust system. As the engine warms up, this condensation vaporizes forming white light smoke that exits through the exhaust pipe.
In most cases, the white smoke should be light and thin and should disappear completely after a few seconds of starting the engine. Also, the white smoke should appear in a cold climate and not in a warm climate.
The second cause of white smoke upon startup is leaking coolant. Now, the purpose of a coolant is to cool the engine. Since it’s located within the engine block, a small leakage can cause white smoke to come out of the exhaust system in the form of sweet-smelling smoke.
One of the causes of leaking coolant is a possible crack in the cylinder head or the engine block. Once the coolant leaks, it combines with engine oil to create a milky appearance in the form of sweet-smelling smoke.
With insufficient coolant in the engine, the engine is likely to overheat causing the head gasket to fail. To those driving modern European vehicles, a crack in the EGR cooler can cause the coolant to leak. Since the EGR cooler is located within the engine, the car might end up combusting the coolant to create white smoke that has a sweet odor.
Leakage in the Piston Ring
The third cause of white smoke upon starting your vehicle is possible leakage in the valve seals or piston rings. If this is the case, then there’s a possibility of oil leaking into the combustion chamber. In the process, the oil is likely to interfere with the fuel/air ratio causing white smoke to come out of the exhaust system.
Now, earlier on, we mentioned blue smoke and we said it’s caused by possible oil leakage. So, in this situation, it’s possible to see the white smoke being accompanied by blue smoke.
Faulty Fuel Injector
Another possible cause of white smoke on the exhaust upon startup is a faulty fuel injector. Here, the fuel injector can either be clogged or leaking on the O-ring causing a lean or rich supply of fuel to the combustion chamber.
In either case, the amount of fuel getting to the combustion chamber will interfere with the fuel/air mixture causing improper combustion. In case of excess fuel in the combustion chamber, the excess fuel will fail to burn completely causing white or grey smoke to come off the exhaust pipe.
Incorrect Injection Timing
In the case of a diesel engine, proper fuel pressure and injection timing is needed to turn the engine on without causing any problems. Now, in case the timing is poor, maybe it’s too early or too late, the engine might end up running rich, resulting in incomplete combustion of diesel fuel. As a result, white or grey smoke will come out of the exhaust pipe when you start the engine.
How Do You Fix White Smoke on Startup then Disappears?
After learning the different causes of white smoke on exhaust then disappears, the next possible cause of action is to diagnose or troubleshoot your vehicle to solve the problem.
Now, depending on your level of profession, you can decide to either take your vehicle to a professional mechanic or fix the problem on your own. In case the latter is your priority, then here are some simple steps you can follow.
- Step One: Smell the Smoke
The first step you should take the moment you notice white smoke coming off the exhaust pipe is to inspect its smell. If the smell is sweet, then it means the coolant is leaking. If it’s not, then it means it’s either a normal condensation or there’s another underlying problem in the engine.
- Step Two: Inspect the Air Intake Gasket
After inspecting the smoke, the next step is to inspect the intake manifold gasket for any cracks or signs of wear. You see, the intake manifold gasket is made of either rubber or plastic and it’s tasked to transport coolant and oxygen to the engine.
In case it’s cracked or damaged, then it means both air and coolant will leak causing the engine to overheat. Also, the mixture of coolant and fuel will cause white smoke, which will exit through the exhaust pipe. So, to fix this problem, you’ll have to remove the intake manifold gasket and repair it.
- Step Three: Inspect the Head Gasket
In case the problem is not the air intake gasket, then you can proceed to the next step, which is the head gasket. Now, the head gasket is tasked to seal the cylinder head to ensure oil or coolant doesn’t leak to the inside.
In case the head gasket is cracked or dented, then there’s the possibility of oil and coolant leaking to the cylinder. If this happens, the engine is likely to burn coolant and oil causing white or bluish smoke to come off the exhaust pipe. So, to fix this problem, you only need to replace the head gasket.
- Step Four: Check the Cylinder Head
In case the head gasket is in perfect working order, the next area you need to inspect is the cylinder head. Now, the cylinder head connects the engine block and the head gasket. Since it’s mostly made from aluminum or cast iron, it’s prone to cracking and warping due to exposure to extreme heat around the engine.
So, if upon inspection you realize that the cylinder head is cracked, then you’ll either repair it via flame spray welding or replace it with a new one.
- Step Five: Check the Fuel Injectors
Again, the fuel injectors need to be checked for any clogging caused by carbon deposits and sludge formation. In case of any, you can use fuel injector cleaners to flush them. In case the fuel injectors are malfunctioning due to old age, you can consider replacing them with new ones.
- Step Six: Replace the Fuel Injector
In case you have a diesel-powered vehicle, one area you need to inspect keenly is the injector pump. In case it’s off, you need to reprogram the computer or simply replace the pump in case you don’t see any progress.
There’s nothing more to add on the issue of white smoke on startup then disappears. Although it’s considered a common phenomenon, white smoke on the exhaust pipe should not be ignored as it can point to a serious problem.
In this guide, we’ve discussed some of the possible causes of white smoke upon starting the vehicle. we’ve also detailed some of the steps you can follow to fix the problem. With this information at your disposal, we believe that the next time you see white smoke coming out of the exhaust; it will be easier for you to fix it.