Hydraulic Valve Lifter – Takes Up Clearance Within The Valve Train

Hydraulic valve lifter engine noise is usually a symptom that something may be wrong with your engine.

All engines make some noise, but when you hear an unusual tapping noise it usually means trouble.

Hydraulic Valve Lifter
Hydraulic Valve Lifter

A hydraulic valve lifter uses oil pressure to adjust a plunger that takes up the clearance within the valve train.

A faulty hydraulic valve lifter usually results in the failure of other components as well.

Are you able to tell when a lifter is going bad, and how to deal with it when it does.

Sticking lifters in most cases are caused by a varnish build up on the lifter surfaces.

If you have hydraulic lifters, the tapping sound can be caused by the accumulation of dirt within the lifter’s hydraulics due to lack of routine oil changes.

This will then cause a drop in the internal oil pressure of the lifters hence the ticking sound.

The lifter is only responding to the conditions and trying to adjust for them. That’s why it is critical to make sure that the lifter is the culprit when chasing any excessive noise.

Not only will this work to create less engine noise, it will also provide longer levels of reliability.

A “collapsed” lifter will allow excessive valve lash and noise.

A tapping noise that gets louder when you rev the engine is probably a faulty hydraulic lifter.

Common Hydraulic Valve Lifter
Common Hydraulic Valve Lifter

Confirming The Noise

The most obvious symptom of a faulty hydraulic valve lifter is the sudden increase in the amount of tapping noise. A faulty lifter has a distinct sound which makes it easily identifiable, even before you lift the hood. Instead of a knock or pinging sound, a faulty lifter will create a tapping sound within your engine. The sound frequency of the valve train noise is one-half the crankshaft speed.

The tapping will occur at a high rate and is more likely to happen when the engine is hot or cold. One of the most common issues in this situation is that the vehicle is experiencing issues with a sticking hydraulic check valve, or that dirt has begun to block up the engine.

What To Check

First, check the engine dipstick to see if the oil level is low. If low, add oil to bring it back up to the full mark. Is the engine still noisy? Check your oil pressure. A low gauge reading (or oil warning light) would indicate a serious internal engine problem. Something is preventing normal oil pressure from reaching the upper valve train components. The cause might be a worn or damaged oil pump, a clogged oil pump pickup screen or a plugged up oil filter. Using too thick a viscosity of motor oil during cold weather can also slow down the flow of oil to the upper valve train, causing noise and wear.

Fixing The Noise

If your car has a faulty hydraulic valve lifter, replace it as soon as possible to avoid further damaging your engine. In most cases, a faulty hydraulic lifter will simply need to be replaced. You might be able to get away with replacing a single bad hydraulic valve lifter depending on the make and model of your vehicle. However, many mechanics suggest that when replacing one lifter, you should go ahead and replace them all. If you find a bad one the others are not far behind.

Conclusion

A hydraulic lifter is designed to ensure that there is zero clearance in the valve train. This leads to a quieter operation of the engine. In many cases, hydraulic lifters have to replaced instead of adjusted.

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