Smoke From The Oil Cap – A car is a complex build-up, it looks easy to handle but can be complex to maintain. Any little change that you notice in your car should be taken seriously because it either means that a problem is starting to develop or it has already developed and it needs important attention. Sometimes, some issues do not need urgent attention, but it is best advisable to attend to every little issue on time

Also, sometimes, a Mechanic may not always be available 24/7 to attend to your car’s issues. So, what do you do in such a situation? You have to do it yourself. Here on CarMart Ng, we want you to buy cars but we also give important tips on fixing car related challenges. Today’s car tip will focus on the reasons and solutions for smoke from oil cap.

oil cap smoke
oil cap smoke

Whenever you start your car, do you notice an engine fume from the oil filler cap? If yes, then you need to roll up your sleeves and get to work. It’s nothing to get flustered about, as the first thing that needs to be determined is, what is the amount of engine fume emanating from the oil filler cap? A little smoke is okay, but when the smoke is more than little then work needs to be done as soon as possible.

How to test for the amount of smoke from the oil cap

To test the amount of smoke coming from the oil cap, to check if it is urgent or not, you will need to:

  • Start your car’s engine.
  • Allow the car to sit. Don’t drive, just let it start.
  • Slowly loosen the oil cap, till it gets removed completely.
  • Check the amount of smoke coming out. If it is small of smoke, you’re good to go.

Safety tips to note when testing for smoke from the oil cap

  • Do not attempt to open the oil filler cap when the engine of your car is still hot. As stated above, turn on the car engine, but do not wait for more than 2 minutes before proceeding to open the oil cap. Remember 2 minutes is the maximum, so you can time yourself.
  • After testing for the amount of smoke from the oil filler cap, please remember to close the tank with the oil filler cap. Do not make a careless mistake by forgetting to close it, then taking the car out on the road. Not only are you risking your life, but damaging the car’s life.
  • Clean up around the tank once you are done testing, so your car does not look like a mess.

After testing for the amount of smoke from the oil cap, if the smoke or fume coming out is much or if it is coming out with some pressure then you may want to start worrying, cause a sign like that is not good news. A need for extra worry comes in when you notice that there is a lot of fume and it is contaminated, then it is an urgent case that needs immediate attention or car servicing.

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Reasons for smoke from the oil cap

There are two reasons for smoke from the oil cap. They are:

  1. When hot fuel does not pass through worn valve stem seals and rings
  2. When fuel does not pass through the worn valve stem seals and worn rings

For a car’s engine to be 100% efficient each part of the car has a specific role to play and if one part defaults in playing its part, a part of the engine can feel it and start faulting. The oil has to flow through the engine system properly to prevent it from any lock or seize. If there is no oil flow, then sooner or later, the various components of the engine will start showing some signs of wear and tear during usage and it will start to show signs of being too thin for use.

If there is proper oil flow, then there would be no lock or seize. When the seals have become thin, some components between the machines become wider than normal and then oil begins to leak through the valves and piston rings, it gets to the combustion chamber which should not be. When oil gets into the combustion chamber, it turns into smoke, and the more you drive the car or the faster you drive the car, the more the oil leakage and smoke production.

Solutions for fixing smoke from oil cap

If you are used to fixing minor damages in your car’s engine, then fixing the smoke from the oil cap should not be tough. But if you’re not used to doing such, no worries you can always call on your Mechanic to help. But here are the solutions for fixing smoke from oil cap.

  •  Check the state of the valves and piston rings. Check for damages in either of the two or the two altogether.
  • If there is any damage in either of them, it needs to be changed. The best solution will be to change the two elements, even if one is only affected. This is best advisable because, an older element won’t be able to withstand the pressure from the new element and soon the element that was not replaced will get spoilt also.
  • Check further for any damages in the engine’s elements.


When changing the valves and piston rings, check around the engine to ensure that there are no pending issues. Fixing one problem in the engine and neglecting another rising issue is being pennywise, pound foolish.

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She is a Writer, Content creator who’s interested in Gender Equality, Women Empowerment, Lifestyle and Food. When she’s not writing, she’s listening to music, watching Nollywood movies or creating business ideas.

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