5 Ways to Reduce Smoke From Diesel Cars and Trucks

(Updated on July 21, 2021)

Diesel engines are notorious for creating a lot of smoke which sends toxic carbon emissions into the atmosphere. The amount of smoke that a diesel engine normally produces is typically dependent on the size of the vehicle. If the vehicle is big like a truck, then the diesel engine needs to provide more power to move it. This means there will be more smoke generated. However, there shouldn’t be excessive amounts of smoke that come out consistently while you’re driving. If there is, then it could mean there is something wrong internally. You’ll want to get this problem fixed soon because too much smoke coming from the engine will likely lower your fuel efficiency.

Top 5 Ways to Reduce Diesel Smoke

If you want to reduce the amount of diesel smoke coming out of your vehicle, below are 5 repair tips that may be able to help you do just that.

1) Air Filter – A diesel engine requires a certain amount of air to enter the combustion chamber first, and then fuel injectors will spray diesel fuel in to mix with it. The result of the diesel combustion process will be carbon dioxide and water being emitted. If enough air was in the chamber, it won’t create as much visible smoke after the combustion process. But if the air has trouble passing through the air filter because it is blocked or clogged, then the chamber won’t have enough air. This will result in a mixture that has more fuel than air which means more fuel is getting burned. If more fuel gets burned, then more visible smoke will be emitted. Therefore, clean or replace your air filter right away.

2) EGR Valve – The exhaust gas recirculation valve is something that has been used in newer diesel vehicles for a while now. The purpose of this valve is to recirculate the emissions from the engine back into the combustion chamber, so they can be reused and burned again. This ultimately lowers the emissions that come out of your vehicle. However, if you have a bad EGR valve, then it will fail to recirculate the emissions. As a result, more visible emissions and smoke will come out of your vehicle. You can fix this problem by repairing or replacing your EGR valve.

Read also: 5 Symptoms of a Bad Front & Rear Differentials and Repair Cost

3) Fuel Injector Timing – The injector of a diesel-powered vehicle must be balanced and timed just right. If the injector fails to spray the right amount of fuel into the chamber at the exact right time, then it will throw off the entire combustion process. Check to ensure that your fuel injectors are not too worn out or misaligned. If so, repair or replace them immediately. You might also want to check with your vehicle’s central computer to ensure there is no programming issue with the timing.

4) Engine Deposits – Diesel engines are not going to stay healthy forever. If you’ve put a lot of years and miles on your engine, then carbon deposits have probably accumulated in the combustion chamber of your engine. You can reduce the chances of this by adding detergent packages to your diesel fuel. These detergents will clean these deposits from places like the combustion chamber and fuel injectors. Normally diesel fuel does not come with these detergents mixed in with it, so you must add it yourself separately. Otherwise, the accumulating deposits will keep causing more smoke to appear.

5) Turbocharger – If you are driving a big diesel-powered vehicle that requires extra power and fuel efficiency, then it is likely equipped with a turbocharger. The turbocharger is able to increase this power because it has the ability to allow more air to enter the combustion chamber. However, a turbocharger also needs a lot of fuel when you try to accelerate from a stop position. Sometimes all this extra fuel will cause smoke to emit during takeoff. The best thing you can do here is to use a catalytic converter to help lower these emissions as much as possible.

3 thoughts on “5 Ways to Reduce Smoke From Diesel Cars and Trucks”

  1. White smoke from Swift Dzire in morning for few minutes only. Then there is no smoke in car. Any problem in car or other issue?

    • It’s very possible it’s just normal condensation (water vapor) burning off in the morning. If it’s more light gray or blueish gray, you may have a small oil leak which burns off for the first few minutes of driving each day.


Leave a Comment