Common Causes of Hydraulic Lifter Noise in Modern Engines

A silent smoothly running engine is an indication of being healthy. However, when that recognizable tapping, or ticking, noise comes out of the engine top, then it is usually the hydraulic lifters. These are minor but significant parts, and knowing their purpose may enable you to properly diagnose the problem.

Understanding Hydraulic Lifter Function and Internal Design

Before you can comprehend the reason why lifters become noisy, you must understand the manner in which they work. Between the camshaft and the valve is a hydraulic lifter which is a self-adjusting point. Its main task is to cut off clearance, or, lash, so that the valve is opened and closed with no play.

There is a smart mechanism within the lifter. It is made up of a hollow and an internal piston or plunger. The gap between them is filled with engine oil which flows in via a small port. This oil is then trapped by a one-way check valve which makes the lifter an under-pressured, non-compressible solid unit. This hydraulic movement takes into account the expansion and wears in the valve train automatically and maintains zero clearance. When this internal system fails to hold pressure properly, the lifter can collapse slightly, creating the clearance that leads to that characteristic ticking noise as components make contact.

Oil Quality and Flow Key Factors in Lifter Noise Development

Engine oil is the blood of any hydraulic lifter. The most popular causes of lifter noise are its quality and flow. The lifter is a precision hydraulic machine, therefore, anything that limits the amount of oil or impairs its quality can lead to issues.

The easiest reason is low oil level; in case not enough oil is present, the lifters will not fill up and will end up being aerated. Nevertheless, the viscosity of the oil is even more important. Too thick oil, usually as a result of cold start or improper grade, drains slowly and may not reach the lifter in time. On the other hand, overheated or fuel diluted oil is too thin to sustain the required pressure within the lifter and spills away.

Oil also disintegrates with time and becomes non lubricating. Queen old, corroded oil may gather varnish or deposits, which fill up the small oil orifices that open into the lifter. A clogged oil filter can inhibit total flow even with a new oil, and even a worn out oil pump might not have the necessary pressure to maintain the lifters at the correct pressure.

Worn Lifters vs. Oil Sludge Diagnosing the Real Culprit

When you get the noise of lifters, the first thing that comes to your mind is that the lifters are exhausted and require change. Although, this has possibilities, it is not always the case. It is important to diagnose whether the problem is a mechanical fault or it is merely a problem with the oil.

Wear of the interior is a real cause of failure. The internal plunger and the cylinder may wear to an inability to form a tight seal over millions of cycles. Check valve may also fail and the oil may leak out very fast. The failure is normally continuous and remains relatively the same irrespective of engine temperature and is usually isolated to one or two ticking lifters.

In more instances, the actual malefactor is the oil sludge or debris. Sludge- is a tar-like thick substance of oxidized oil, contamination of fuels and by-products of combustion. The inlet port of a lifter is incredibly small and thus easily blocked by this sludge making it unable to fill up. In this case, the lifter can be in excellent mechanical condition, it is simply starving to death because of lack of oil. The problem can be more common, it can affect several lifters, and it can be relieved in the short run by changing the oil or injecting the engine with a couple of pumps of engine flush, only to re-occur when the sludge breaks loose and re-blocks the passages.