Engine noise under load-FAQ

Vehicle Noise
Vehicle Noise

Engine Noise Under Load- What can it be !

Don’t turn your back on car 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.

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.

Be sure to properly inspect and verify the root cause of the noise, as it can be tricky to pinpoint. Consequently you don’t want to replace the entire engine only to find out that the noise was coming from a fuel pump or loose baffle.

We’ve put together this quick guide for diagnosing common engine noises to help you avoid potential damage. In the event of strange or unusual engine sounds, remain calm, grab an automotive stethoscope, and be on the lookout for:

Engine Noise Under Load-Symptoms

Engine Noise Under Load-Possible Cause

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).

Low oil pressure Check oil pressure at the oil pressure sending unit port on the engine with a gauge. .
If oil pressure is okay, replace sending unit.
Detonation or spark knock May be due to low octane fuel, carbon buildup in combustion chambers, over advanced ignition timing, inoperative EGR, or engine overheating.

Check all of these to determine the cause.

Loose torque converter bolts Inspect the torque converter bolts and flywheel.
Repair as required.
Cracked flywheel – automatic transmission Inspect the flywheel bolts and flywheel.
Repair as required.
Excessive connecting rod or main bearing clearance Inspect connecting rod bearings , connecting rods and crankshaft. Use Plastigage or a feeler gauge to measure assembled bearing clearances.
Excessive Piston clearance Piston slap may be due to worn cylinders, worn pistons or excessive piston-to-cylinder clearance
Engine Noise Under Load
Engine Noise Under Load

Other that engine noise under load there are other noises that can also cost you time and money if ignored !

  • 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.

  • Grinding Engine Noise

If you hear a deep grinding engine noise, this may not be your engine, but your brakes. Check your front brake pads for signs of complete wear. If the metal is grinding against the cylinders, replace your brakes.

Engine Noise Under Load-If the noise does continue, check with a good mechanic for correct diagnosis.


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