Many drivers just ignore engine noise, and hope that it’ll just go away on its own.
Chances are it won’t, and you’ll wind up with an even bigger problem.
Be sure to properly inspect and verify the root cause of the engine noise, as it can be tricky to pinpoint.
Consequently, You don’t want to replace engine parts only to find out that the engine noise was something else.
Some common mistakes are noises coming from loose baffles or mechanical fuel pumps.
In the event of strange or unusual engine sounds, remain calm, grab an automotive stethoscope.
Finding out where the noise is coming from is the first step.
Because drive belts, alternators, compressors, air pumps, and fuel pumps all make noise, it can be quite a job to narrow to narrow down the cause.
Therefore it is good practice to first remove the belts and run the engine to see if the noise disappears. To prevent overheating be sure to only run the engine for a short period of time.
We’ve put together this quick guide for diagnosing common engine noises to help you avoid potential damage:
A cold piston knock for up to a minute and a half after starting a cold engine may be normal. This may be due to increased clearance between the pistons and cylinders. But once the engine warms up, the knocking noise should disappear.
If you hear a low rumble or knocking noise when the engine is warm, the most likely cause may be a bad rod bearing on the crankshaft (which may lead to bearing failure and/or rod breakage or crankshaft damage).
Clicking and Tapping Sounds
An audible tapping or engine clicking noise coming from the front of your car will definitely draw your attention. Consequently your ears will perk up and you will tune in to the noise, open a window and try to figure out what is going on.
The tapping or clicking will increase as you accelerate and become faster. This could be what is known as a ‘tappet,’ or the upper valve train.
As a result the causes could be a number of issues starting with a worn part. It could also indicate that the oil pressure is low. Check your oil pressure gauge when you hear this sound and follow guidelines to determine the exact problem. Take the dipstick out and make sure you have enough oil in there.
Deep Knocking Noises
These are usually a sign of deep trouble and yes, you should be worried. ‘Rod knocking’ sounds could mean that one part deep inside the engine has worn out. If your rod bearings have worn completely out or become too loose, it is only a matter time before the bearings fail. In this case, you should not use the car until the knocking engine noise has been fully and properly tested, diagnosed and repaired.
Rattling and Whining Sounds
If you hear a whining or rattling engine noise from your car when you accelerate it could possibly be that your camshaft belt is badly aligned or slipping. Have your camshaft belt checked or look it over yourself if you have the right knowledge. It should really be fixed by a good mechanic, otherwise you could have more trouble further down the road.
Squealing When Accelerating
This is an unmistakable sound and it is quite ear splitting. This is your fan belt telling you it is in pain. The fan belt can loosen over time and when you start your engine and the fan belt (often called the serpentine belt) can squeal when the rubber teeth underneath it start to drag. If the fan belt is loose it will not be able to move at the same tempo as the pulleys which control it, hence the squealing noise. If this happens with your vehicle you should look in the manual for repair procedures and tighten it correctly. It may have worn enough to need replacing.
Even those with lots of experience in car repairs can be fooled by the meaning of engine sounds. To make matters more confusing, sometimes minor or innocent-sounding sounds may signal a severe problem, while a loud, menacing thud might be fixed with a $20 part.
But, here’s something that’s for certain: you shouldn’t ignore car engine noise. Doing so could lead to a catastrophic situation where your engine needs to be replaced. Plus, disregarding engine sounds could threaten your safety–and result in a breakdown at the worst possible moment. While you always have the option of taking your vehicle to a mechanic for a diagnostics test, you can often get a good idea of what’s troubling your engine by listening to it.