Step by step troubleshooting instructions on how to fix abnormal engine noises.
This article pertains to all non electric vehicles.
Difficulty Scale: 4 of 10
Tools and Supplies Needed
Protective eyewear and gloves
Wrench and socket set
Hydraulic jack w/stands
Some engine noises are normal for example: some Chevy and Ford engines have short
skirt pistons or all roller valve train, a minimal amount of engine ticking noise
is normal. Fuel injectors also make a slight clicking noise when the engine is idling.
These noises are normal and no repair is required, but if unexplained noises exist,
the following steps are the most common causes.
Step 1 - Check the engine oil level, an engine
depends on clean oil to lubricate the internal moving parts, if the oil level is
low or dirty it can cause internal engine parts to malfunction. For example: a valve
lifter is responsible for holding valve train clearance to a minimum, if the oil
level is low or dirty it can cause the lifter to fail which will allow excess valve
train clearance creating engine tapping or clicking noise. In extreme cases it can
cause one of the many bearing surfaces to fail causing permanent engine damage.
An engine making a slight noise, changing the engine oil and filter with the manufacturers
recommended weight (viscosity) oil sometimes helps. Visit -
oil changeStep 2 - A squeaking noise could be generated by
the engine accessories, accessory mounts, serpentine belt or drive pulleys. When
an accessory, accessory bracket, belt or drive pulley fails it can make a rattling,
squeaking or tapping noise. These sounds are centrally located near the front of
the engine. With the engine off, check the tension of the belt/belts, it should
be at medium tension a loose or worn belt can make a loud squealing or chirping
noise, check the belt tensioner and the size of the belt to make sure the right
belt is installed. To isolate the origin of the noise, remove the serpentine belt
and start the engine. Visit -
If the sounds disappears an accessory, accessory bracket, belt or pulley has
failed. With a flashlight inspect the brackets and pulleys that connect the alternator,
air conditioner compressor, power steering pump, and air pump if equipped. Look
for signs of rust (reddish pounder), this indicates a broken or loose metal part
rubbing together, which can generate squeaks and ticking noises. If the brackets
look okay rotate each accessory pulley by hand and check for hard spots or a seized
Step 3 - If a tapping or ticking noise from the
upper half of the engine remove the valve covers. Each valve utilizes a spring that
returns it to its original position, closed. If a valve spring has broken or a cam
lobe is worn down it will cause the engine to create a tapping or clicking sound
due to the excess clearance. To test for this condition, remove the ignition coil
connector, ignition system or fuel pump fuse to disable power to the ignition or
fuel system. Have a helper crank the engine over while watching the rocker arms
or cam lobes, making sure all valves are traveling the same amount. If one or more
lobes are traveling less than the others the engine has a flattened cam lob and
the camshaft needs to be replaced, or the hydraulic lifter/follower (where applicable)
has collapsed and will need to be replaced. Also inspect the condition of the valve
springs, using a flashlight and a small mirror to aid in the inspection to look
for broken springs. If a broken valve spring is discovered replacement is required
to correct the problem. When checking valve springs look at the height of the valve
springs and retainers in the closed position, they should be exactly the same height.
If one valve is higher or lower something is wrong with the cylinder head the valve
or valve seat and needs to be repaired.
Replacing a Camshaft