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 clicking noise that is originating from the engine of your car. These warning signs make you wonder what is the exact cause of the oil pressure being low. The moving parts need oil for lubrication, which right now is in short supply. If you insist on driving in spite of the engine protesting thus, there are high chances of damage to the parts, like a tappet, or the upper valve train.
Importance of Oil Pressure
The oil pump merely maintains the flow of oil to the engine. 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 that lets the oil in. There can be many reasons behind the less-than-required oil pressure, resulting in a scored engine oil pump, and damaged:
- Camshaft bearings
- Overlay of crankshaft, main as well as rod bearings
- Small end bearings of connecting rods
- Engine timing/idler/accessory drive gear train bearings
What Causes Lowered Oil Pressure
The first thing to inspect is the dip stick. Take it out, and after wiping it, insert it again. After withdrawing it for the second time, check the level of engine oil. Ensure that it is between the markers representing the minimum and maximum amounts of oil present in the engine. If it is, then the cause lies somewhere else. If it is low, either there's a leak somewhere, or the engine is burning more oil than is normal. However, before looking elsewhere, it is important to check whether the viscosity of the oil 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.
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, and also 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, can also be the cause of such pressure. The other causes, leading to this trouble, are leakage of oil between the oil pump and engine block, cracks in the oil galleys, and malfunctioning galley plugs.
An oil pump is a fine-tuned instrument, and is considered to be the heart of an automobile. When that malfunctions, your vehicle can come to a stand still. One of the causes is the excessive clearance in the oil pump itself. Depending on the type of oil pump, which your vehicle is employing (gear type or rotary), the amount of the clearance required varies. Then, 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 lack in pressure after changing oil, 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 the engine is heated to a great extent. The problem arises after you have driven the vehicle for some time. The engine oil absorbs the heat, and becomes less viscous. This 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 is best handled by an expert mechanic. It must be looked into as soon as possible, to limit the amount you spend on the car repairs, which may go out of hand if you let the car seize on you.