Why cars consume oil, causes and how much they should consume

So, to begin with, it should be noted that car engines should consume a very moderate amount of oil, since, ultimately, we are going to have minimal consumption due to the oil lubricating the cylinder wall and, more specifically, the movement of the piston in the cylinder. So, the piston rings are going to retain the largest amount of oil so that it does not rise to the combustion chamber. But part of that oil, of that oil film that forms around the cylinder wall, ends up filtering into the combustion chamber and there is consumption. That is inevitable, but this consumption has to be minimal or at least moderate. Now, how much is that minimum consumption? How much consumption do we have to see in an engine? For example, every 3,000 miles or 5,000 kilometers to say that it is still normal consumption? There are several figures that are used, the most logical figure and the one that is most true is the following. An engine that is operating in good condition should not use more than about half a liter every 3,000 miles. An engine in good condition will use that, around half a liter or less. And those who have a car that is halfway through its life and is well preserved will agree with me that it does not use more than a quarter, if at all, half a liter every 3,000 miles. That is what we are generally going to see and it is normal. Now, if for example we have a car that already reaches the figures of 1 L or more every 3,000 miles, then it is very likely that we already have a problem. Now, what should we check? If our car is using more than 1 L of oil every 3,000 miles or 5,000 kilometers, what we should check quickly and easily are oil leaks, which are not uncommon in cars that have already gone through a lot of miles or kilometers, and the other is the PCB system. And the two are very related and very important. The PCB system is very important because if, for example, we have problems with leaks due to the oil pan gaskets or a seal, even if we repair those leaks, if the PCB system is not working properly, we will have leaks again, the leaks will reappear. The PCB system is very important because it is responsible for ventilating the oil pan. As we know, the oil pan is not a sealed system. The oil pan is a place where there is a lot of agitation, there are temperature changes. So, all of that has to be ventilated and the PCB system is responsible for that. The PCB system consists of some ducts, hoses and the PCB valve. So, it is very important that this system is working properly. The best thing to do is to check the PCB system every time we change the oil. The other possible scenario for high oil consumption in a car engine is mechanical problems with the engine, which are often accompanied by blue smoke from the exhaust. If we have a car that is using a significant amount of oil, more than 1 L R every 3,000 miles or 5,000 km, and we also see blue smoke from the exhaust, either when starting it at idle or when we are running, it is likely that we have mechanical problems. What are the problems related to oil, high oil consumption? Mainly loose piston rings, rings that do not seal properly, that are already loose and will cause a greater amount of oil to pass into the combustion chamber and burn, therefore it will be consumed. The other problem is the valve guides or seals, which also cause this problem. Therefore, if we have these symptoms of high oil consumption in the engine, we do not have leaks, the PCB issue is working and we have smoke in the exhaust. Gray smoke, between gray and black, at least it will indicate that we have to check what has to do with mechanical situations in the engine. And that's it, thank you very much for watching the video, thank you for making it to the end and see you next time.