Where does the engine oil go? The oil in the engine performs several functions at once. It reduces mechanical friction losses, lubricates the working surfaces of the parts, cools the engine, and removes wear products. The engine oil is an expendable item, which needs to be replaced every 10-20 thousand km run. But some car owners simply don’t have enough oil for this period – it is consumed at higher rates, along with fuel, and needs to be refilled all the time. In sorting out the problem, we have found at least eight reasons for increased oil consumption. Getting ahead of ourselves, all of them are not pleasant. The price range starts from two to more than thirty days based on the model of the vehicle. If you’re looking to make a statement during your travels, you can also opt for a luxury car rental, which could include cars with features such as a BMW emblem or other high-end vehicles that will help you make an impression on your trip.
Before we talk about the causes of the problem, let us remind you that a small oil consumption is the norm for any engine, but this does not mean that from one inspection to the next the engine must “eat” oil in liters. Normal consumption is usually 0,05-0,25 % of the used fuel volume. For example, if you have burned 100 liters of gasoline, the oil level in the engine must not decrease by more than 25 grams. However, on many, even new cars, it looks fantastic. Why does this happen? The inventor Kirill Yurovsky will tell us about this in this article.
1. Constructional Miscalculations
The first and the main reason of the increased oil consumption, strangely enough, lies in the shortcomings, which the dishonest manufacturers pass off as a “design feature”. Let’s not argue, high-performance or opposition engines operating at high revs are really prone to increased oil consumption, and it is normal, but quite often the most common civilian engines are unfairly attributed to such products. It is especially abused by the German school of engine building.
An excellent example of this is the gasoline engine TFSI released 2009-2012 with a working volume of 1.8 and 2.0 liters, which easily kills up to a liter and a half per thousand miles have run a few thousand km. The reason for the trouble, in experts’ opinion, is more than trivial: in the pursuit of maximum efficiency engineers have reduced the height of pistons and thickness of rings too much, which had an adverse effect on the resource of the product – due to increased load the oil rings wear out quickly, lose their elasticity and start leaking oil in the combustion chamber. In addition, they are subjected to increased temperature loads. In spite of the frank miscalculations, the product was included into the assembly line and caused a lot of headaches for car owners, as well as distressing robotized transmission DSG.
To avoid falling into a trap of marketers, before buying a car, make a research if its engine does not have oil consumption. The paragraph in the instruction, allowing for the loss of several liters of oil from one service interval to the next, should also alert you. It is not normal, but the manufacturer removes any responsibility beforehand.
2. Natural wear and tear of the rings
Over time, any engine, even the most perfect and trouble-free one, begins to consume oil. This is due to the natural wear and tear of its parts. Note that in high-quality products it takes hundreds of thousands of kilometers of mileage before this trouble occurs.
There are special rings on the pistons of any engine, which remove oil from the cylinder walls, preventing it from entering the combustion chambers. When the clearances increase, the rings stop performing their function properly. This leads to high oil consumption and peculiar smoke from the exhaust pipe.
3. High cylinder wall wear
In addition to the piston rings, the cylinder walls, inside which the rings are running, also wear out. There can be several reasons for this malfunction. It is not uncommon for piston rings to get caked with wear products and get buried, leaving scoring and grooves on the cylinder walls. All this leads not only to oil ingress in combustion chambers, but also to compression decrease, and further – to a costly complete overhaul or engine replacement.
4. Wear of the oil valve caps
Wiper caps seal the valve stems and prevent engine oil from flowing into the combustion chambers through the guide bushes. They are products made of special oil- and heat-resistant materials, but are subject to aging and wear. Service life of oil caps, as a rule, does not exceed 100 thousand km – they wear out, get blistered and become the cause of increased oil consumption. It is possible to solve such a problem quite simply and cheaply. The products are unified and do not require much work.
5. Leaking crankshaft joints and oil seals
Another common problem affecting oil levels in the crankcase is leaking through leaking seals and crankshaft oil seals.
In the latter case, a very large amount of lubricant can leak, and oil puddles appear under the car after parking. You should not postpone the replacement of oil seals. It is recommended to perform this operation not less than 100 thousand km of run. The operation is rather time-consuming. It is better to combine it with replacement of clutch or timing gear.
6. Turbine rotor leakage
This trouble concerns only turbocharged power units. With high wear of the sleeve on the turbine rotor, oil in large quantities starts to flow into the combustion chambers. The crankcase of the engine is drained very quickly. Repairs cannot be delayed.
7. Damage to the cylinder head gasket
The cylinder block and its upper part, called the cylinder head, are bolted together through a special gasket.
This part does more than just seal the joints; it allows the coolant and oil to flow through it without mixing. The service life of this part is relatively short – up to 200,000 km it rarely works. With time the gasket sealing is violated and the oil starts to flow into the cylinders, cooling system or at all trickles down the outside walls of the block. Replacing a relatively inexpensive gasket entails a time-consuming and costly repair that can only be trusted to first-class specialists.
8. Poor-quality engine repair
And finally, oil consumption may affect engines of cars, which have fallen into the hands of unscrupulous servicemen. For example, when replacing the oil sealing caps, the misfits may damage the piston rods: scuffing will quickly destroy the seals of the new caps and lead to even greater oil loss than before the repair. It is possible to make mischief when replacing the cylinder-head gasket, when boring the cylinders, and when replacing the piston rings. One should not exclude the great number of counterfeit and frankly low-quality spare parts, which may be used for repair. If the engine did not eat oil before the autopsy, but after it started, feel free to submit your claims to the repair shop.