Diagnosis of an engine noise

Here are a few tips to help you diagnosis where a noise is coming from in the engine. First try and verify it is actually an engine noise as many times the noise will come from other components and lead you to believe it is from the engine. Take and remove the serpentine drive belt and start the engine and see if the noise is still there as many times the noise is coming from an accessory that the belt drives and not the engine itself. Do not drive the vehicle with the belt off and only run for a brief time as many vehicles will over heat as the water pump is driven by the belt but is ok for a test to remove the belt. If the noise is still there after removing the belt then put the belt back on as not to cause any damage and then try and determine if the noise is coming from the top of the engine or the bottom. If you have a stethoscope this works well and if not a long screwdriver to the ear will work for a substitute. Once you determine the general area of the noise then you want to try to further narrow it down and if the check engine light is on see if there are any codes as this too would help in the diagnosis. If from the top of the engine most likely a lifter noise or a rocker arm making the noise and if from the bottom most likely a rod bearing. To try and determine which cylinder is the cause of the noise try to cancel the cylinder out and see if the noise changes and if it does or goes away you know what cylinder has the problem. For example say you have a lower end noise in the engine and when canceling out cylinder number 2 the noise changes and almost goes away then you know you have a rod bearing on the number 2 cylinder causing the noise. It is always better to try and pinpoint the noise before taking the engine apart so you know where to go and don’t waste time taking things apart that you don’t need to. Normally the best way to cancel out a cylinder is to remove the injector connector for that cylinder this way with no fuel the cylinder wont fire. Hope these tips help you in diagnosing your engine noise and for help with this or any other auto repair task just visit us at http://www.expertcaradvice.com/