The purpose of oil is to lubricate the whole engine system especially those components that are moving such as the piston, crankshaft, piston rings, connecting rod, and other vital components.
But in some cases, the rocker arm may not receive oil while other engine components are well-lubricated.
Don’t forget the position of the rocker arm, it is the furthest part to the oil pump. The rocker arm is at the top of the engine while the oil is at the bottom which is the sump. So we can rightly say that the two are at opposite ends of the engine.
So what can cause the rocker arm not to receive oil?
1. Weak oil pump: When the oil pump becomes weak, it will lack the power to push oil to the rock arm. As stated earlier, the rocker arm is at the upper part of the engine. Other components such as the crankshaft and bearings are closer to the oil pump, so it is easier for them to receive oil, but difficult for the rocker arm because of the location. At this point, the oil pump is not totally bad, but weak and it lacks sufficient power to supply oil to the rocker arm.
2. Blockage in the oil gallery: There are holes in the engine that oil passes through, and these holes are very thinning for the oil to maintain good pressure. If the holes are big, the oil will lack pressure. Due to the size of the oil gallery, the hole can be blocked. And when the hole blocks it prevents the oil from getting to the rocker’s arm. But what usually blocks the oil gallery you may be asked? There are a few things that can cause that which include oil sludge and foreign particles.
If you allow your oil to stay too long in the engine, it can cause the oil to form a sludge. Such sludge is capable of blocking the oil line. That is why you must change the oil according to the manufacturer’s prescription. And you should also buy quality oil that doesn’t become sludge quickly.
When there are foreign particles in the oil, it can also block the oil passage. These foreign particles are due to a clogged oil filter. When the filter is clogged it will not be able to trap oil dirt, so much dirt can clog the oil passage will later prevent the oil from getting to the rocker arm.
3. Spun bearings: Spun bearings are when the journal bearings are stuck to the crankshaft and sometimes cause engine seizures.
When you have spun bearings, it will then block the oil passage in the crankshaft which prevents oil from getting to the rocker arm. The oil passes through the crankshaft before getting to the upper part of the engine. So if there is an obstruction on the oil passage, then it will prevent the crankshaft from getting to the up. Too much clearance between the bearings and the crankshaft will also cause low oil pressure which can prevent oil from getting to the top.
4. Wrong cylinder head gasket: if you use the wrong cylinder head gasket, it can sometimes block the oil passage from the engine block to the cylinder head. Before you install a head gasket, ensure you check all the holes to ensure that the oil passage hole is not blocked.
5. Unsuitable oil: if you use the wrong oil for a specific engine, then the oil may not be able to pump it. That is why you should check the the oil to ensure it is suitable for your engine so that the oil pump can pump the oil. Ask a professional or check the owner’s manual for the right oil for your engine.
Note: You should also remember that there are holes in the rocker arm itself. If you notice that a specific cylinder rocker arm does not receive oil, you can check the holes in the rocker arm.