A car engine is made up of several moving parts, all working together within tight tolerances. While some noise is natural, some sounds are more “normal” than others, and a keen ear may be able to detect something is wrong before significant damage is done.
A ticking noise is a good example of this. You may hear a loud click or tick emitted from a car’s engine bay soon after starting the vehicle or while idling, accelerating, or decelerating the engine.
Although some clicking, clunking, screeching, or ratcheting noises from a few components, such as the fuel injectors, PCV, and purge valves is, normal, a persistent and loud tick may be a sign of worn-out valve lifters, excessive valve gap, exhaust leaks, bad spark plugs, bad bearings, or rod knock.
While most of these issues are harmless, some may spell doom for your engine if left unchecked, especially if the underlying cause is a lack of lubrication.
So, if you perceive that your engine started to make an uncharacteristic ticking noise, you have come to the right place. In this guide, we’ll explore the causes of engine ticking or clicking, from very mild to catastrophic, as well as ways to fix it.
7 Causes of Ticking or Clicking Sound From the Car’s Engine
Engine ticking is often caused by poor lubrication, which can result from low oil levels, the wrong type of oil, or pressure. The most frequent causes of ticking or clicking noises include faulty valve lifters, improperly adjusted valve gaps, or rod knock. Additionally, drive pulleys or an exhaust leak from a gasket or faulty spark can also be the source of the ticking sound.
The main causes of engine ticking noises are noted as follows:
1. Lack of lubrication
Improper lubrication can cause problems with the connecting rods or valvetrain, which will produce ticking noises. The oil system is an essential part of the engine, as it lubricates all the metal components, reduces friction, and carries away heat.
In case of a serious lack of oil pressure, you may even get a red warning light on your dash; if this happens, you should stop the engine as soon as it is safe to do so in order to prevent major damage.
Low oil pressure may be caused by a number of issues, such as:
2. Excessive valve gap
The valve gap or lash is the clearance between the rocker arm or camshaft lobe and the top of the valve stem or lifter. If the gap is too high, there will be an audible ticking noise as the rockers hit the valves from a higher distance.
The valve gap must be adjusted periodically on some vehicles (especially Hondas or older models). Most modern engines will have hydraulic valve lifters which automatically keep valve lash at a minimum when working properly, eliminating this problem.
3. Worn-out or unlubricated valve lifters
The most frequent source of an audible tick from the engine bay is the hydraulic valve lifters or tappets. These are part of the engine’s valvetrain, which is located in the cylinder head. They work by using hydraulic pressure from the engine oil system to keep the valve gap at a minimum across the entire engine temperature range.
If the oil pressure is low, the little piston in the tappets may get stuck, causing the characteristic tick of metal-to-metal contact as the camshaft lobes hit the un-lubricated lifters several times per second.
4. Rod Knock
The connecting rods have the difficult job of translating the crankshaft’s rotating motion into linear motion, which drives the pistons up and down the cylinder bores. The rods attach to the crank through the big-end journal bearings.
This interface has a very small clearance that allows for the oil to lubricate the surfaces and ensure smooth operation. This oil seal may be broken with improper lubrication, leading to direct metal-on-metal contact, which will be perceptible inside the cabin as a ticking noise.
In extreme circumstances, repeated operation in this state may increase the temperatures exponentially and eventually result in spun bearings, causing severe bottom-end damage.
Note: This will be more like a clunking sound in more severe cases than a mild tick.
5. Exhaust leak
The exhaust manifold gasket is the most common source of engine bay exhaust leaks. It sits between the exhaust headers and the cylinder heads, and its job is to ensure the combustion gases stay where they should – inside the engine. If there’s a leak in the gasket, the sound of the exhaust passing through this pinhole might make a ticking noise.
Other common areas for exhaust leaks are along the welds and flanges through the piping. While an exhaust leak won’t do any damage to your car, it is a health and environmental hazard, on top of making the engine run less efficiently. Therefore, it should be addressed as soon as possible.
6. Worn-out pulleys And/or bearings
Besides reciprocating assemblies, like the ones we’ve seen so far (such as the rods, pistons, valves, tappets, rockers, etc.), engines also have rotating components, like the drive pulleys. These components sit on bearings, which can become worn out over time. While these will more often than not make squirrely noises rather than ticking noises, in some situations, they might emit a noise that’s close to a tick as well.
7. Faulty Or Misaligned Spark Plugs
A spark plug that isn’t seated properly will let exhaust gases through, which might cause a ticking noise. Furthermore, if you fitted spark plugs that are too long for the engine, the tip of the spark plugs might be impacting the top of the piston crown, causing a ticking noise.
This is a bit out of the left field, but could cause damage to the piston and to the spark plug and result in a loss of engine performance. Check the service manual for the right spark plug specifications when replacing them.
Not All Ticking Noises Are Bad
As mentioned before, a running engine is a complex machine, and some noises are unavoidable. It’s important to be able to tell apart a normal ticking noise from a bad one. Here are some of the “ok” ticking noises you might hear:
1. Cold starts
Some ticking noise after the engine starts from cold is common, especially if it has been sitting for way too long. That’s because the cylinder heads are usually the highest part of an engine, so the oil drains down over time, causing the lifters to be unlubricated at start-up.
It might take some time for the engine to warm up and pump enough oil through the cylinder heads and valve tappets for them to resume their normal operation, so the ticking should subside after a few seconds.
Some oil filters have check valves built-in to prevent the oil from draining out completely once the engine is shut down, so buying high-quality filters may help alleviate this issue.
2. Fuel injectors
A fuel injector is essentially an electro mechanical valve opening and closing several times a second, and this motion can be quite noisy in some cases. This is particularly noticeable in diesel (especially older ones), direct-injection petrol, and some LPG-converted engines. It might be difficult to tell the ticking noises apart, making these engines a bit harder to diagnose.
3. Other solenoid valves
A few other solenoid valves throughout the engine can make noise, such as the purge or PCV valves. While these don’t normally operate at the same high frequencies as the fuel injectors, a particularly old or faulty valve may make a persistent ticking noise, so make sure to check those as well.
2 Ways to Diagnose a Ticking Noise in Your Car
Now you have identified your engine is making a ticking noise – that’s the easier part. So how do you find what part is causing the problem? Here’s how:
1: Check the oil level
If you hear a suspicious ticking noise, you should first check the engine oil level. If it’s too low, then you likely have one of the problems associated with insufficient lubrication.
2: Listen around the engine bay for the source of the noise
There’s no easy way around this; to find the origin of the ticking noise, you’ll have actually to hear the engine. Obviously, a trained ear will be able to do this faster and more easily. Listen closely and carefully at idle and give the engine a few revs to try and pinpoint where the noise comes from.
If your oil level is low, pay special attention to the top of the engine for valvetrain issues and the engine block for knocking rods. If the noise seems to come from one side of the engine, it is probably a leak from the exhaust manifold gasket. If it comes from the front of the engine, it might be from the drive pulleys.
How to Fix a Ticking Engine
The right course of action to fix your ticking car’s engine will depend on the noise source. Assuming you managed to diagnose this correctly, repairs will usually consist of replacing the faulty component making the ticking noise. This will range in difficulty from very simple, if it’s a spark plug or a drive pulley, to complete bottom-end rebuild if it’s a rod knock.
1: Change the oil and find the leak
Most ticking sounds in engines are due to faulty lubrication. Changing the oil and filter at the correct intervals will keep your car happy. If you noticed your oil level is low, now is the time to top it up and, crucially, identify where it has gone to.
Do you have an external leak from a seal, or is it an internal leak? Regardless, you will have to find and fix the underlying problem; otherwise, your ticking noise will return (or worse, your engine may be damaged and require costly repairs).
2: Adjust the valve gap
This should be the next step if your vehicle has an adjustable valve gap. Consult your service manual for the correct clearance values. Remove the cylinder head cover and, using a feeler gauge, measure the gap between the top of the valves and the mechanism that pushes down on them (which can be either rockers or the camshaft).
The valves must be readjusted if any of these values are larger than the manufacturer’s recommended value. The process depends on what kind of valve gear your engine has and will entail either turning some screws and locknuts or using calibrated shims to bridge the gap.
3: Replace the valve lifters
If the hydraulic valve lifters are no longer working as they should, even though the oil system is fine, then they will need to be replaced. While the lifters themselves are relatively cheap, this operation can be quite costly.
Firstly, there can be a lot of them (equal to the number of valves in the engine), and secondly, because the lifters are usually located under the camshafts or rocker’s arms, making their replacement a convoluted process that requires dismantling most of the cylinder heads. If you are not comfortable enough with DIY, this repair is better left to a professional.
4: Rebuild the bottom end
This should be your last port of call, so make sure you have exhausted all other possibilities before sentencing the rods. Fixing rod knock is the stuff of nightmares, as it essentially requires taking the entire engine apart. A professional mechanic should also do it unless you are absolutely sure you know what you are doing.
Frequently Asked Questions
Is the engine ticking a Serious Problem?
Engine ticking can range from perfectly normal to a precursor to disaster. In the end, how serious the problem is will depend on the source of the ticking. Some ticking from the injectors or solenoid valves is no cause for concern, but if it is rod knock, you must be prepared for some pretty expensive repairs.
Can you drive a car with a ticking noise?
Some mild engine ticking won’t render the car undrivable. However, as with many engine issues, continuing to drive in this condition can exacerbate the problem and result in higher repair costs down the line. If your engine starts to make uncharacteristic noises, your first port of call should be to check the oil level as soon as possible.
How much does it cost to fix a ticking engine?
If you can get away with just changing the oil and filter, that will likely run you between $50 and $100. Depending on what other components may need replacing, that can rise to $200 to $500 dollars.
Replacing the lifters will probably run $500 to $1,000, most of which is labor, so you can save quite a lot of money if you can do it yourself. If you are unlucky and the problem is caused by a knocking rod, this may cost you upward of $1,500 dollars as the entire engine must be rebuilt.
Will an oil change stop engine from ticking?
An oil change might be enough to fix a ticking engine if your engine is making a ticking noise due to having the wrong oil, a bad oil filter, or a low oil level and if the lack of lubrication has caused no permanent damage.
Why is my car making a ticking sound after an oil change?
Poor lubrication will often cause engine ticking noises. If you just changed your oil and your engine started to tick, first make sure the oil level is right.
Remember, you will likely have to top off the oil a second time after starting the engine for the first time after an oil change.
Secondly, make sure you add the right type of oil. Adding an oil that is too thin will cause the oil pressure to be low at higher temperatures.
Written By
Victor Faeda
Victor is a Mechanical Engineer BSc and certified Automotive Mechatronics technician from Portugal. He worked as an intern mechanic for Volvo and has been fixing his own vehicles for over 10 years. Writing and cars are his passion, so now he combines the two by creating content around the automotive industry. He specializes in automotive technology and maintenance.