You start your engine like normal, but you hear an engine rattling noise, you’ve never heard before.
Subsequently, an engine rattling noise, can spring up from a number of different sources.
So, the first part of diagnosing an engine rattling noise, is always to determine, where it is coming from.
Then, establish when engine rattling noise occurs, and how your engine behaves, when the noise starts.
It can be a little nerve-racking, as some sounds can be indicators of serious problems, while others have simple fixes.
Responding appropriately to the sounds your engine makes, can prevent problems from getting worse. As a result, saving you time and money.
It could be, an engine rattling noise when accelerating, some kind of spark knock or just a general engine noise. However, there’s one thing that’s true of them all, it’s never a good idea to just leave it alone.
First, a quiet engine makes for a happy driver. But, once a rattle or some other odd noise emerges, your peace of mind may evaporate. So, you have a great many moving parts, inside your engine. However, as they wear, you may hear rattling noises, from a variety of sources.
Common Reasons For Engine Noises:
Oil And Fuel-Related Noises:
Let’s start with rattling noises under the hood, that are caused by, oil or fuel-related problems:
Reason, Low Engine Oil Level
So, your engines oil pump, circulates engine oil through the engine, lubricating the internal moving parts. But, over time, the engine can consume, burn or leak oil. And, if the oil level gets too low, you can have a situation, where the oil pump sucks air. Then, the air gets pumped through the engine, along with whatever oil is remaining. As a result, this can cause, a engine rattling noise or ticking noise from within the engine.
Solution
Shut off the engine immediately. Use the oil dipstick, to check the engine oil level. Pull out the dipstick, wipe it off with a paper towel, then reinsert and check the level. It should be, between the two marks on the dipstick. If the level on the dipstick is low or nonexistent, add the correct oil for your vehicle. If you have a major oil leak or are burning a lot of oil, the cause should be corrected. Otherwise, you’re likely headed, for an engine failure.
Reason, Pinging From Low-Octane Fuel
So, your engine needs fuel, with the correct octane rating to operate properly. If you hear a pinging or a engine rattling noise when accelerating, low-octane fuel could be the cause. Pinging can also be the result of, carbon deposits, a bad knock sensor, overheating or incorrect ignition timing. (also called pre-ignition or detonation).
Solution
Fill your fuel tank with premium fuel and see if the problem goes away. If not, you will have to track down the exact cause. Get this fixed immediately, because it can damage or destroy your engine.
Noises From Internal Engine Parts:
There are many moving parts within your engine that can cause a rattling noises:
Reason, Timing Chain Or Belt Noise
Your engine’s timing chain or belt connects the crankshaft to the camshaft, for proper operation of the valve train. Modern overhead cam engines, have very long chains and belts, which use hydraulic tensioners to keep the chain taut. But, over time, the nylon chain guides wear, and the tensioners, can’t manage the slack in the chain or belt. You hear a rattling noise, made by the chain or belt whipping around, without tension, inside the timing chain cover. Consequently, this noise rises and falls, with the engine (RPM)s.
Solution
Replacement of the hydraulic tensioners and the chain guides, may be necessary. If you have a timing belt, check it for wear. And, replace it, if you are near the prescribed replacement interval.
Reason, Valve Train Noise
The valve train is the system in your engine, that’s driven by the camshaft. And, opens and closes your engine’s valves. The valve train, allows fuel into the cylinders and lets the exhaust gases out. Consequently, the lifters being pushed by the camshaft lobes, that do the actual opening and closing of the valves. They can be either mechanical or hydraulic. If they get worn, stuck or out of alignment, a engine rattling noise may be heard, especially at low (RPM)s.
Solution
Depending on the type of lifter and the exact cause, the fix may involve adjusting the valves. Also, using a detergent additive, if the lifters are coated with varnish and sticking. Lastly, replacing the lifter if it is defective.
Reason, Piston Slapping Noise
If you have a high mileage vehicle, with a worn engine, the pistons may fit in the cylinders very loosely. During a cold start, this may show up as a rattling noise. It usually goes away, once the pistons expand, from the heat of the engine.
Solution
Fitting oversize pistons, will solve the problem, but this is a very expensive fix. It may not be worth doing on a high mileage vehicle, that has lost most of its value. If you can live with the engine rattling noise, it is unlikely to cause any further issues.
Reason, Connecting Rod Knocking Noise
Connecting rods, transmit the rotary motion of the crankshaft, to the up and down motion of the pistons. Rod knocking noises, are the result of wear from insufficient or dirty oil. And, can wear down the surfaces of the bearings. As a result, this causes excessive clearances, between the bearings and the crankshaft.
Solution
Once you hear the engine rattling noise, you will need major engine work, which will be very expensive. If not fixed, some or all of these rotating parts, can fail and destroy the engine.
Rattling Noises From Other Parts, Attached To The Engine May Include:
- Drive belt issues
- Bad water pump
- Broken harmonic balancer
- Defective starter
- Bad fan clutch
- Failing idler pulley
- A cracked flexplate
- Loose heat shielding
- Loose torque converter bolts
Conclusion
So, there are many different types of engine rattling noise, that can come, from many different parts of your engine. Some have simple, cheap fixes. Others, can be very costly.
BY DANNY BENDER
