Reasons that may not require engine repair (Mitsubishi Colt 4)

Oil pressure can be low for several reasons that do not require engine repair. These include: low oil level; the oil filter is clogged; liquid or diluted oil; oil pump pressure relief valve stuck open; the oil pump oil intake tube is damaged.

Low oil level

Checking the oil level is essential before deciding to overhaul the engine. When the oil level is low, it is difficult for the oil pump pickup tube to draw enough oil to maintain proper pressure in the engine's lubrication system. Low oil pressure under these conditions is a small evil compared to the damage that can cause low oil pressure. Probably the best preventative measure in this case is to check the engine oil level at least once a week and add oil as needed.

Clogged oil filter

The simplest or most obvious cause of low oil pressure is a clogged oil filter. Unfortunately, there is no way to say for sure that this is usually the result of carelessness or mistakes. If the oil has not been changed during the time the engine suffered from low oil pressure, then the oil and filter should be changed.

Liquid or diluted oil

The idea of buying oil that is too thin (i.e. low viscosity) is pretty silly. If you are using oil that was purchased for the purpose of lubricating a car engine, it is almost impossible to buy oil that will, by itself, cause low oil pressure. Some people may disagree with the statement that using thick, high viscosity oil will cause high oil pressure. This is often true. However, if the engine lubrication system, oil pump, and bearings are in good condition, even low viscosity oil will provide the necessary oil pressure.



Another thing is diluted oil. Oil becomes diluted in several ways. Perhaps the most common way is the following. When the engine is running, especially after starting, some exhaust gases escape past the piston rings and into the crankcase. These gases contain some unburned fuel. The unburned fuel dilutes the engine oil. This diluted oil can cause low oil pressure. But what can happen even more critically is that the unburned fuel, combined with moisture in the crankcase, can form an acid that can damage bearings and their surfaces long before the low oil pressure caused by the dilution can damage the engine.

Another way: Engine oil can become diluted by engine coolant (coolant). If the cylinder head gasket starts to leak, or if the cylinder head or block cracks, coolant can leak into the combustion chamber and/or crankcase and dilute the engine oil.

Although low pressure due to diluted motor oil can be determined by a simple oil change, the question is: does the engine need a major repair due to a failure caused by diluted motor oil? Another question is, how much damage has been caused by diluted motor oil? A simple oil change may increase its pressure, but the engine may already be damaged and this damage must be repaired before catastrophic consequences occur.

Oil pump pressure relief valve stuck open

All engines are equipped with an oil pressure relief valve in the oil pump. The valve's job is to limit the oil pressure to a level that prevents the oil filter from becoming a shrapnel grenade. Occasionally, the relief valve will stick open, allowing oil to be pumped by the oil pump and back into the oil pan. This is a very difficult fault to diagnose and may require a complete engine overhaul.



If time is not a critical parameter, remove the oil pan and install a new oil pump. Although it is possible to repair the pressure relief valve, there is little point in removing the oil pan and doing the repair "just in case".

Damaged oil pump oil pickup tube

When the oil pump is removed during the installation operation of a new pump, check the feed pipe for possible damage. If the pipe is cracked or loose, the oil pump will not be able to suck oil from the oil pan. This will cause low oil pressure. Before replacing the oil pump, make sure the feed pipe is in good condition.

The original can be found on the website (MitsubishiMan.ru)