Knocking under the hood? Could be connecting rod

When you drive your car, do you hear a light knocking or pounding sound coming from under the hood? If so, is it most noticeable when engine speed is constant?

If you answered YES, you could have a bad connecting rod in your suspension.

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What is a connecting rod?

The connecting rod connects the piston to the crankshaft. It can rotate at both ends so that its angle can change as the piston moves and the crankshaft rotates.

Extreme connecting rod wear is indicated by low pressure and high oil consumption. The connecting rod is under tremendous stress from the reciprocating load represented by the piston, actually stretching and relaxing with every rotation, and the load increases rapidly with increasing engine speed.

Failure of a connecting rod is one of the most common causes of catastrophic engine failure in cars.

So, if you feel you have a bad connecting rod, take your car in for an inspection. Your technician will inspect connecting rods for bending, twisting, and cracking. Some connecting rods can be reconditioned by a tech and reused. Others require replacement.

If you do need to replace, get the rods that are designed to be the strongest piece within the rotating/reciprocating assembly. Click here for more information.