Have you noticed some strange noises coming from your engine lately? Or maybe it’s idling rough or losing power? There’s a good chance you have a bad hydraulic lifter. But what exactly does that mean? And what will it cost to fix?
A hydraulic lifter is a small but important engine component that opens and closes the valves that let fuel and air in and out of the cylinders. When a lifter goes bad – usually due to a lack of oil pressure or buildup of sludge – it can cause all sorts of problems.
In this guide, you’ll learn:
- What hydraulic lifters do and why they go bad
- The common symptoms of a faulty lifter
- The dangers of driving with a bad lifter
- How much it costs to replace hydraulic lifters
- A step-by-step guide to lifter replacement
- Expert tips for preventing lifter failure
If you notice any of the lifter issues below, don’t hesitate to get it checked out. Driving with bad lifters can lead to further engine damage down the road.
Table of Contents
What is a Hydraulic Lifter and What Does It Do?
Hydraulic lifters, also sometimes called tappets or valve lifters, are small parts located in the engine valley below the cylinders. They connect to the pushrods which open and close the intake and exhaust valves.
The lifter’s job is to take up space between the camshaft and valves while also ensuring the valves fully close. This maintains proper combustion compression and allows the valves to “float” to account for temperature changes and wear.
Hydraulic lifters use oil pressure to maintain a small gap between the lifter and valve. A tiny plunger inside the lifter acts as a shock absorber to smooth out engine operation.
Most modern engines have roller lifters while older ones use flat lifters. Each cylinder generally has two or more lifters. So an 8-cylinder engine can have 16 lifters or more.
When functioning properly, the hydraulic lifters ensure smooth valve timing and compression. But when one goes bad, it can hamper engine performance.
What Causes a Hydraulic Lifter to Go Bad?
Hydraulic lifters can fail due to:
- Low oil pressure – Without adequate pressure, the lifter can’t ride properly on its cushion of oil. Lifters depend on oil for lubrication and their hydraulic operation.
- Thick, sludgy oil – Contaminants and condensation buildup in old oil can gum up lifters and prevent them from moving smoothly.
- Worn camshaft – Excessive wear between the camshaft and lifter allows too much play. This also prevents the proper lifter movement.
- Bent pushrod – If something causes the pushrod to bend, it will alter the lifter’s motion and valve timing.
- Improper adjustment – Over time, adjustments to the valvetrain components can get thrown off. This strains the lifters.
- Debris – Small bits of gasket material or engine grime can get lodged under lifters and jam them up.
When one or more lifters begin to fail, you’ll quickly notice changes in how the engine runs. And it will only get worse from there if ignored.
Common Symptoms of a Bad Hydraulic Lifter
Listen for these telltale signs of faulty hydraulic lifters:
The most common symptom of a stuck open lifter is a loud tapping or knocking sound from the engine. This happens when the open valve keeps striking the piston as it moves up and down.
The noise varies with engine speed and typically goes away once the engine warms up. It’s most noticeable at idle. This sound indicates it’s time to replace the lifters before further damage occurs.
Check Engine Light
If the powertrain control module (PCM) detects an issue with the valvetrain operation, you may see an engine warning light illuminate. The computer can sense when the valves open and close improperly.
Diagnostic trouble codes like P030X (“Cylinder X Misfire Detected”) often accompany lifter problems too.
Along with the audible knocking, bad lifters make the engine idle unevenly. Since the valves can’t open and close normally, combustion suffers. The engine will sound rough and feel like it’s misfiring.
When crud builds up under a lifter, it can pop the lifter out of its bore in the engine block. Engine oil will then leak from the gap between the lifter and block. You may notice oil spots under the vehicle if this happens.
Loss of Power
As hydraulic lifters wear out, the valvetrain loses its normal “lash” clearance. This throws off valve timing, duration and lift. The result is decreased engine performance – your ride just doesn’t have the same pep and response.
Ignoring lifter issues allows increased wear between the valve tips and cylinders too. Compression and combustion continue to suffer unless the problem gets addressed in a timely manner.
Dangers of Driving With a Bad Hydraulic Lifter
You don’t want to continue driving once you detect bad lifter symptoms. Here’s why:
- The constant tapping can lead to bent pushrods or valves. Not only are repairs more involved at that point, but bent valves increase the risk of catastrophic engine failure.
- Small debris from the excessive wear can start to circulate in the oil. This contaminates the oil and accelerates damage to bearings and other critical components.
- As compression drops, your engine has to work harder to provide sufficient power. This strains systems from the fuel injectors to the catalytic converter.
- If a collapsed lifter allows valves to remain partially open, it throws off combustion temperatures promoting premature ignition, burning issues and loss of power.
Addressing bad hydraulic lifters as soon as possible reduces further repairs down the road. In a worst case scenario, you could be looking at a full engine rebuild!
How Much Does it Cost to Replace Hydraulic Lifters?
Replacing all the lifters in an engine can run $1000 or more in total repairs. Let’s break that down:
The hydraulic lifters themselves range from $5 to $30 each, depending on the brand and quality. Most engines require 8-12 lifters for a full set. Plus there’s the cost of new pushrods, oil, gaskets and other incidentals.
Some people use lifter additives to try to clean sludge and improve lifter performance, but there is no scientific proof that they work, and they may have negative side effects on your engine.
This is where most of the expense lies. First the mechanic has to properly diagnose which lifter is bad. Then there’s a significant amount of labor just to access them buried deep in the engine valley.
With the intake manifold and valve covers off, replacing the actual lifters is the fastest part of the job. The labor cost for replacing the hydraulic lifters is between $100 and $1000, depending on the engine design and the shop rate.Some engines are easier to work on than others, and some shops charge more than others.
Total Replacement Cost
In total, the average cost to replace a set of hydraulic lifters ranges from $300 to $1,000 parts and labor. A professional can usually charge between $1,000 and $2,500 to replace one or more lifters.The exact cost will depend on:
- Number of cylinders/lifters
- Accessibility difficulty
- New pushrod requirement
- Type of vehicle (make/model/year)
Shop around among reputable mechanics to find the best value. Then you can breathe easy knowing your lifter replacement cost is fair.
Step-by-Step Guide to Replacing Hydraulic Lifters
Wondering what’s involved in the lifter replacement process? Here are the basic steps:
1. Diagnose the Bad Lifter
First you’ll want the mechanic to verify the source of the engine noise or misfire. Through a visual inspection and diagnostic testing, they can home in on the bad hydraulic lifter.
If it’s accessible, the mechanic may try wiping the lifter bore clean and adding some freshly filtered oil. Then run it to see if the noise goes away. That confirms the culprit.
2. Access the Lifters
Gaining access to lifters buried deep in the engine valley varies by vehicle. Some require removing the intake manifold or cylinder heads. Expect extra cost and labor time if extensive disassembly is needed.
Many modern engines at least require taking off covers, throttle body components and fuel rails. New gaskets here add to hydraulic lifter replacement cost.
3. Remove and Replace the Lifters
With access clear, the mechanic removes the lash adjusters/lifters along with the pushrods. These get inspected for wear patterns indicating issues like oil starvation or debris.
Before inserting the fresh hydraulic lifters, oil galley passages and lifter bores get thoroughly cleaned. Some mechanics recommend a break-in oil additive too. If the camshaft looks worn, plan on some extra repairs.
4. Reassemble the Engine
The new hydraulic lifters and pushrods get installed in reverse order of disassembly. Various adjustments may be needed to achieve proper preload. Then the cylinder heads, intake manifold and other components go back on.
An oil change finishes up a thorough lifter replacement job. Some shops recommend coming back after break-in miles to recheck adjustments.
FAQ About Bad Hydraulic Lifters
Here are answers to some commonly asked questions about identifying and fixing faulty hydraulic valve lifters:
How Long Can You Drive With a Bad Lifter?
Driving any length of time with one bad lifter risks further engine damage. The knocking and tapping can quickly snowball valve, cylinder and piston problems. Schedule repair ASAP.
Can You Just Replace One Lifter?
You can replace only the bad lifter if positively identified. But often debris contaminates the nearby ones too. Since the labor accessing them is the same either way, best practice is to replace the full set.
Will a Bad Lifter Damage the Engine?
Absolutely – an untreated bad lifter can wreak havoc inside the engine. Bent pushrods and worn camshaft lobes just scratch the surface. Irreparable cylinder/piston/valve damage often results if ignored too long.
Hydraulic lifter problems significantly affect engine performance and come with risks if driving a vehicle with bad lifters. Diagnosing and replacing faulty lifters promptly reduces the chances of secondary damage down the road.
Knowing what typically causes lifters to fail allows you to be proactive too. Stick to the manufacturer’s maintenance schedule and use quality oil and parts. Catching minor lifter noise early before it turns into major engine repairs saves money.
While a full hydraulic lifter replacement job runs $300-1000$ on average, that pales in comparison to a full engine rebuild! Hopefully this guide gave you confidence in identifying bad lifter symptoms, understanding replacement costs and making an informed repair decision.