Ⅰ.What are the causes of large oil loss?
Normal break-in
The engine has reached its normal lifespan and it's time for a major overhaul.
Abnormal running-in
The causes of abnormal wear and tear include early wear and tear due to product quality and improper use. The causes of early engine wear include using substandard engine oil, failing to change the engine oil and oil filter beyond the specified period, deeply pressing the accelerator pedal to start the engine when it is cold, running for a long time without engine oil, running for a long time in a high-temperature state, running for a long time under overload at high speed (engine speed exceeding 4000r/min), and running for a long time in poor air quality (excessive dust content). Running the engine without replacing the air filter upon expiration, insufficient oil pump force, low oil pressure, clogged oil passage, etc., will all reduce the engine's service life and cause premature wear.
Ⅱ.What are the damaged parts with high oil consumption?
The wear of the cylinder liner and piston will increase the clearance of the cylinder wall, causing some engine oil to seep into the combustion chamber and catch fire.
② Wear of the piston rings, weakened or broken elasticity of the piston rings, and misalignment of the piston rings (where several piston ring openings are in a straight line) can cause poor sealing, allowing some engine oil to seep into the combustion chamber and catch fire.
③ Aging and damage to the valve oil seal can also allow some engine oil to enter the combustion chamber and burn, especially the aging and damage of the intake valve oil seal, which is more likely to cause engine oil to enter the combustion chamber and burn.
④ The blockage of the engine exhaust pipe (the oil chamber is connected to the engine intake pipe) causes excessive pressure in the oil chamber, resulting in some engine oil flowing into the combustion chamber and burning.
⑤ The collision between the oil passage of the cylinder gasket and the cylinder can also cause some engine oil to seep into the combustion chamber and burn.
⑥ The turbocharger also consumes some engine oil when starting and stopping the machine.
Since the exhaust gas turbocharger seals the lubricating oil by the balanced pressure of intake and exhaust, there is always a small amount of engine oil leaking out when starting and stopping the machine. This is also a characteristic of all engines that use exhaust gas turbochargers.
Ⅲ. How to eliminate excessive oil consumption?
① Check whether the exhaust gas pipe is unobstructed. If it doesn't work, clean or replace it. Drive for a while longer to check if the engine oil is low and if blue smoke is still coming from the exhaust pipe.
② Measure the cylinder pressure. If the cylinder pressure is normal, it indicates that the oil burning is caused by the aging and damage of the valve oil seal. Replace the valve oil seal.
③ If the cylinder pressure of a single cylinder or multiple cylinders is lower than the normal value, then the only way is to disassemble the cylinder head to check whether the cylinder gasket is in the oil passage, the degree of wear of the cylinder bore, the degree of wear of the piston, the elasticity of the piston ring, etc. If it is only the oil passage, replace the cylinder gasket to eliminate it. If the cylinder bore and piston are worn too much, the cylinder liner should be repaired and the piston and piston rings replaced. If the wear of the cylinder bore is not significant, the piston and piston rings can be replaced. If the problem lies with the piston rings, then the only way to eliminate the fault is to replace all the piston rings.
Ⅳ. How to Determine and Rule out Oil Burning in a Car Engine?
Engine oil burning is a relatively serious malfunction phenomenon and should be detected and treated as early as possible.
① Judgment Method
Excessive clearances among engine components, improper assembly and adjustment, or prolonged wear and tear can all cause engine oil to enter the combustion chamber through different channels and be burned off. The severity of engine oil burning can be identified and inspected by observing the color of the exhaust gas from the exhaust pipe. When the engine is idling, dark blue smoke is emitted from the exhaust. If the engine is briefly accelerated, excessive dark blue smoke will be discharged from the exhaust pipe, resulting in more obvious smoke. Sometimes, by observing the oil filler port, one can also notice a large amount of smoke or pulsating smoke, which can determine that the engine is burning oil.
Causes and Solutions
1) Excessive wear of the engine's related components can lead to an overly large fit clearance, causing excessive engine oil to splash onto the cylinder wall, far exceeding the oil ring's oil-scraping capacity. If the clearance between the crankshaft bearing shells is too large, engine oil will leak from one or more pressure-lubricated bearing shells.
Main components: Piston rings, pistons, crankshaft journal bearings, connecting rod bearings, crankshaft thrust plates.
The best way to handle it: Replace these main components.
2) Oil burning caused by improper assembly or failure of engine-related components.
Main components: The valve oil seal has fallen off or aged.
The best handling method: Replace the valve oil seal.
3) Poor quality of car engine repair and improper selection of parts are also causes of oil burning. For example, piston rings. If the clearance of the piston rings is too large and the tension is insufficient, the engine oil on the cylinder wall cannot be scraped clean. This oil will enter the cylinder and be burned off, resulting in oil consumption. Poor-quality components are also highly likely to cause engine damage. For instance, the erosion of the connecting rod bearing bush leads to the damage of the engine crankshaft. The engine is severely worn.
V. What are the main causes of engine oil leakage?
If engine oil leaks out, tighten the bolts and/or replace the gasket and oil seal if necessary.
② If the oil level is improper or the oil dipstick reading is incorrect, when the vehicle is parked on a level ground, wait for a sufficient period of time for the oil to flow back and check whether the oil level is correct.
③ The crankcase ventilation system is blocked or there is a malfunction of the components.
④ Turbocharger failure.
Ⅵ. How to Troubleshoot oil leakage faults?
① The gaskets have aged, including the oil pan gasket, valve cover gasket, front and rear crankshaft oil seals, and camshaft oil seals. If these components have problems, they can only be replaced. In actual maintenance, the surfaces of most components that need to be sealed require the application of sealant. The application method is: remove the old sealant adhering to the surface where the sealant is applied and the mating surface. Thoroughly remove the adhered old sealant from the sealant application surface, fixing bolts and bolt holes. Wipe the application surface and mating surface of the sealant clean, and remove the adhering water, grease and foreign objects.
② Oil filling port. Each time you add oil, be careful and steady to avoid overflow and dripping.
③ When tightening the bolt of the oil drain port after each oil change, be sure not to apply excessive force, especially for the aluminum oil pan. Otherwise, after several times, it will lead to poor sealing and oil leakage.
④ If the oil filter seat is not sealed tightly, causing oil leakage, the sealing gasket should be replaced.