Low Oil Pressure Causes

Most often, you come to know about the oil pressure in your car by the flickering of the oil pressure warning light or by the tapping or engine clicking noise that is originating in the engine of your car. These warning signs make you wonder what is the exact cause of low oil pressure. How you react to these signs also determines the health of the engine as its moving parts need oil for lubrication which right now is in short supply. If you insist on driving on when the engine is protesting about the oil, there are high chances of damage to the parts, such as a 'tappet,' or the upper valve train, inside the engine and of engine seizing on you.

Importance of Oil Pressure

The oil pump that supplies oil to the engine, merely maintains the flow of oil to it. The resistance to the flow which results in the creation of oil pressure inside the engine is due to the action of the input valves in the engine block which lets the oil in it and the clearance between the bearings and the crankshaft journals. There can be many reasons behind the less than required oil pressure which may cause scored engine oil pump and damage to:

• Camshaft bearings.
• Overlay of crankshaft main as well as rod bearings.
• Lifters
• Small end bearings of connecting rods.
• Engine timing/idler/accessory drive gear train bearings.

What Causes Lowered Oil Pressure

Engine Oil
The foremost place to start investigating is the dip stick. Take it out and after wiping it, insert it again. After withdrawing it for the second time, inspect it for the engine oil that is sticking to it. Check, if it is between markers representing the minimum and the maximum amount of oil present in the engine. If it is, then the cause lies somewhere else. If it is low then either you have a leak somewhere or the engine is burning more oil than that is normal. However, before looking elsewhere it is important to check whether the viscosity of the oil in the engine is as specified by the manufacturer or not. In the cold season, if it is the motor oil viscosity that is causing the low oil pressure, it may pay to switch to some less viscous engine oil.

Clearance
One of the main reasons is the excessive bearing clearance which can be due to wear and tear of the old engine parts or loose assembly tolerance. The high bearing clearance allows the oil to leak and oil pressure to drop. Increased engine noise as well as pounding are the signs one should look for before visiting a good mechanic. Along with the high bearing clearance, wearing of the lifter bores and clearance between camshaft journals and bearing as well as end play in the cam can also be the cause of the pressure. The other causes leading to this trouble are leakage of oil between oil pump and the engine block, cracks in the oil galleys and malfunctioning galley plugs.

Oil Pump
An oil pump is a fine tuned instrument which is considered as the heart of an automobile. The malfunction of an oil pump, as you have seen, can bring your vehicle to a stand still. One of the causes is the excessive clearance in the oil pump itself. Depending on the type of oil pump your vehicle is employing (gear type or rotary), the amount of the clearance required varies and even small debris sucked in by the oil pump can become a cause of its malfunction and low oil pressure.

You may have also observed the low pressure after oil change, and it is considered as normal. However, it is safer to put some oil in the filter before installing it on the engine. Another time when you are most likely to face low pressure is when it is hot. The problem arises after you have driven the vehicle for some time, the engine oil has absorbed the heat and has become less viscous. In such a situation, the less than normal oil viscosity makes it difficult to maintain proper oil pressure in the engine. Along with the situations mentioned above, low oil pressure at idle is a situation that one must let an expert mechanic handle. It must be looked into as soon as possible, to the limit the amount you spend on the car repairs which may go out of hand if you let the car seize on you.