Reasons that require engine repair (Hyundai Elantra J1)

Oil pressure can be low for several reasons/which will require engine repair. If you decide to repair your engine due to low oil pressure, pay special attention to the following:

• condition of main bearings and main journals of the crankshaft;
• condition of connecting rod bearings and crankshaft journals;
• clearance in camshaft bearings and camshaft journals;
• condition of the oil line plugs and condition of the oil line.

Condition of main bearings and main journals of the crankshaft

Damaged main bearings can cause low oil pressure or even a clunking noise. The sound will resemble a high-frequency dull knock. Replacing main bearings is part of any engine overhaul.



When the main bearings and/or main journals of the crankshaft are worn, the clearance between the bearing (liner) and the journal increases. Increasing the clearance allows oil to easily escape from the space between the bearing and the journal. This oil escape causes a decrease in oil pressure. The way to eliminate this malfunction is to grind the crankshaft and/or replace the crankshaft and bearing liners.

Condition of connecting rod bearings and connecting rod journals

Bad connecting rod bearings cause dull knocking sounds, some higher in pitch than main bearing knocks but lower in frequency. The knocking sound from connecting rod bearings only appears when the working mixture in the combustion chamber is ignited. The main bearing knocking noise occurs every time a spark jumps in any of the spark plugs.

Like main bearings and main journals, connecting rod bearings and journals can cause a loss of oil pressure if the clearance between them becomes too large. The noticeable increase in clearance allows engine oil to easily escape from the space between the bearing and the crankshaft journal. Oil leakage causes a decrease in oil pressure. The only way to fix this problem is to regrind or replace the crankshaft and replace the bearings.

Camshaft bearings and camshaft journal clearance

Often overlooked by inexperienced repairmen, excessive clearance between the camshaft journals and camshaft bearing can also cause low oil pressure, just as large clearances in the connecting rod or main bearings can. It is sometimes thought that because camshaft bearings are not subject to the same loads as connecting rod and main bearings, they require no more than a simple visual inspection. Nothing could be further from the truth. On most overhead cam engines, bearings are virtually impossible to replace without completely disassembling the engine. Overhauling an engine without carefully checking the bearings and camshaft journals runs the risk that the overhauled engine will still suffer from low oil pressure. Always check the bearings and camshaft journals carefully.

Condition of oil line plugs and oil line itself

If the oil lines are clogged with deposits from poor maintenance, or if the plugs at the ends of the oil lines are leaking, the engine will suffer from low oil pressure. When rebuilding an engine, take the block and cylinder head to a workshop and have them hot cleaned. This ensures clean oil lines through which oil can flow freely.

Knocking of main bearings

Not only does increased bearing clearance lead to low oil pressure, but low oil pressure is usually accompanied by knocking sounds. This knock is a high-pitched, high-frequency sound coming from deep within the cylinder block. The name "high pitch" refers to the musical pitch of the tapping sound. The name "high frequency" refers to the number of knocks that occur during one engine cycle. If the frequency of knocks is approximately the same as the number of flashes in the cylinders, then the main bearings require attention.

Time and effort can be saved by having a sample of engine oil analyzed. Some shops can analyze a sample of engine oil from your engine. The analysis results will tell you how much bearing and crankshaft material is in the oil. If the amount of these materials is high, this indicates the need for engine repair.

Knocking of connecting rods

The knocking sound of connecting rods can be very similar to the knocking sound of main bearings. Its tone can vary from higher than that of the main bearings to lower. The main difference is the lower repetition rate. This happens because the connecting rod itself, unlike the main bearing, is subject to load (high pressure) only when a flash occurs in the corresponding cylinder. The connecting rod knock frequency will correspond to one knock per one engine operating cycle. This is explained by the fact that a cylinder with a faulty connecting rod only works once per engine cycle.



The problem with analyzing bearing knock by sound remains difficult to solve until you are very familiar with the engine you are working on and can say to yourself, "Is that a high pitched or low pitched, high frequency or low frequency bearing knock, different from the knock that would come from another component if it were bad?".

Valve knocking

Some engines may have valves that have manually adjustable clearances. On these engines, valve noise can often be eliminated by adjusting the valve clearances. Even in engines with hydraulic tappets, valve knocking does not always require engine repair. There is an opinion that carrying out serious repairs to valves causes deterioration of the sealing ability of piston rings. As with other opinions, there is an element of truth in this one. When the valves' sealing ability increases, the pressure in the combustion chambers increases so much that it becomes close to the value that was on a new engine. And the piston rings are no longer new. They start to leak compression pressure. The result is that the operation of the valves causes deterioration of the piston rings. What is happening in reality is that rings have now replaced valves as the weakest link in some chain.

The conclusion from the above is that if the engine has enough wear and requires valve grinding, then it probably needs a major overhaul. This is a pretty bold statement, and in some cases no repair is required, such as when the valve rocker arm has failed due to a manufacturing defect.

Camshaft wear

Some engines have chronic problems with camshaft lobe wear. Sometimes this happens because the camshaft designers chose the wrong material. Often camshaft failures are the result of poor maintenance or lack of lubrication.

Before deciding whether camshaft wear will require a complete engine rebuild or simply replacing the camshaft and valve lifters (if any), consult with your local auto repair shop. If this type of engine has a reputation for being prone to this type of cam failure, then replacing the camshaft is probably the best option. On the other hand, if the engine in question is not prone to this type of failure, then a worn camshaft may be an indication of another hidden problem that requires engine repair.

Low compression

As an engine wears over time, the ability of each cylinder to withstand and create pressure decreases. This can be due to several factors. First, the valves no longer seal as well as they did when the engine was new. After tens of thousands of kilometers, piston rings do not seal as well as they did when the engine was new. Over time, the cylinders become slightly oval in shape, and the piston rings no longer seal as well as before. When an engine reaches this state, it is considered "tired".

Low compression in one of the cylinders is usually the result of one of two defects.

One of them is a burnt, bent or poorly sealing valve. Another is a damaged cylinder head gasket. The best way to differentiate between these faults is to use a cylinder leak indicator.



Low compression in one of the cylinders is usually the result of damage to one of the components.

• Never use low quality parts.
• Always check carefully for additional damage while performing the main work. A catastrophic failure of one part can cause failure of other parts. It can also be an indicator of other nearby faults.
• Never repair your friends' cars.

Oil leaks

Relatively new engines do not require major repairs simply because small oil leaks are found on the garage floor. However, older engines may have so many leaking areas that the only practical and logical way to repair it is to remove it and rebuild it. When a car owner decides to remove the engine to eliminate leaks, it makes sense to overhaul the engine

Oil burnout

Two faults can cause excess oil to burn: oil leaking past the piston rings and past the valve guides. Each malfunction has its own symptoms and solutions.

Oil penetration past the piston knees

The most common symptom associated with piston rings that are wearing out and allowing oil to pass past them is blue smoke when accelerating. Before you suspect the rings, there are a few other things you need to check.

If the crankcase pressure is too high, it can force oil past the piston rings into the combustion chamber. If the crankcase pressure is too low, oil can enter the intake tract. When either of these happens, the oil is burned as the air-fuel mixture ignites. While these symptoms are identical to those of worn piston rings, this problem is fairly easy to fix.

The engines are equipped with a positive crankcase ventilation (PCV) system. The purpose of this system is to capture hydrocarbon-containing gases that pass past the rings from the combustion chamber and direct them back into the combustion chambers for re-burning. When the PCV system becomes clogged, the pressure in the engine crankcase begins to drop. This pressure drop is the result of the intake manifold vacuum pulling gases out of the crankcase, and air not replacing the gases in the crankcase due to the clogged PCV system. The result is that when the pressure drops, the intake tract pulls in increased amounts of oil through the ventilation system. If the PCV valve itself is clogged, the crankcase pressure increases and the oil passes by the oil scraper rings during the intake stroke.



Another typical cause of oil burnout, which is somewhat similar to oil passing past the piston rings, is sticking or "sticking" of the oil scraper ring. a "stuck" ring can often be freed with a high detergent oil. Also, a large number of oil additives can clean piston rings. Consult with your auto repair shop staff regarding which oil to use for the specified purposes.

Oil penetration through valve guides

If blue smoke comes out of the exhaust pipe when engine braking, it is probably the result of worn valve guides. When engine braking occurs, the pressure in the intake manifold decreases significantly and the vacuum increases. A higher vacuum causes the combustion chamber to empty. Excess clearance between the valve stem and the guide bushing allows combustion chamber vacuum to draw air from the top of the cylinder head, under the valve cover. This air is saturated with oil. Oil is drawn in along with the air and burned in the combustion chamber.

A malfunction associated with oil penetration into the valve guides can be easily eliminated without major engine repairs. However, piston rings, main and connecting rod bearings, camshaft and camshaft bearings may also have the same wear as the valve guides. You need to see if you are simply trying to eliminate the symptom or if you are making the engine capable of running for another few tens of thousands of miles.