Your engine could make plenty of weird noises, depending on what has gone or is about to go fully kaput. If it is a rhythmic pinging sound that progressively increases as you step on the throttle, otherwise called rod knock, likelihood is your engine is running on borrowed time. Ignore it for long enough, and yes, it may result in the engine completely seizing, and also you, stranded on the side of the road. And it isn’t a matter of “if” but “when”.
But how are you going to tell if it’s rod knock or something else, like a the sound of a failing water pump bearing or a tappety valve? Since all of them sound very similar, your best bet is to enlist the assistance of somebody with a trained eye — or ear, on this case. Even the detonation out of your engine running lean or a defective knock sensor can often result in sounds which can be much like rod knocks.
Should you occur to be mechanically inclined, you almost certainly know that diagnosing the origin of the sound is a superb approach to kick things off. If the ticking sound is toward the underside of the engine and gets noisier as you press the throttle pedal, it’s likely rod knock. Then again, if it’s closer to the highest of the engine and progresses relatively slowly, as demonstrated in this YouTube video, it’s probably something related to the valvetrain.
Inspecting the engine oil for excessive metal shavings is one other way of confirming your suspicions of a rod knock, provided it falls in step with the remaining of the symptoms, like low oil levels and reduced oil pressure. For all this to make sense, though, it is important to grasp the role of rod bearings and the way they work inside an engine.
Understanding the basis cause and fix it
There is a bearing (typically of a softer multi-metal variety) sandwiched between the crankshaft and connecting rod, with a skinny layer of oil acting as a barrier. This oil separates the bearing’s surface from that of the crank journal, so when the engine is low on oil, the barrier weakens, leading to direct metal-to-metal contact. Ergo more friction and, consequently, increased wear. Because engines often run on tight tolerances, this oil-starved, friction-induced gap is enough for the connecting rod to rattle around, causing the metal-on-metal sound that you just hear as rod knock. That is different from engine knocking, and may also be a results of poorly designed rod bearings (as was the case with certain BMW M cars) or ones which can be damaged or completely worn out.
Depending on the engine’s “condition,” you may perhaps proceed driving the automobile, but it surely’s generally not beneficial. As you may probably tell, it isn’t one among people who’s going to magically go away. It must be fixed in some unspecified time in the future. The longer it takes, the more serious your repair bill goes to be.
Fixing rod knocks is comparatively straightforward — you replace the bearings, which, in all fairness, is simpler said than done. This kind of work, which generally involves taking apart the engine, is amongst the automotive maintenance jobs best left to the professionals. Assessing the extent of harm inside your engine will determine whether it’s price repairing or just getting a substitute engine, since the increased friction could have damaged the crank’s surface (which you’ll fix to a certain extent), amongst other things. But generally speaking, these engine-out jobs are inclined to be pretty expensive.
This Article First Appeared At www.jalopnik.com
