Signs & Symptoms of Bad Motor Mounts

by Jason Medina

Motor mounts are extremely important vehicle parts that stabilize and align a vehicle engine inside the engine compartment. Although small in size and relatively cheap in cost, motor mounts can cause tremendous mechanical problems if they break or go bad.

Excessive Engine Vibration

One of the most common symptoms of bad motor mounts is excessive engine vibration, especially under heavy acceleration and/or engine revving, when engine movements are most pronounced. Motor mounts serve to stabilize and reinforce a vehicle engine; bad motor mounts allow excessive engine movement to occur, movement that is pronounced when excessive engine power is created. Bad motor mounts allow excessive engine movements to cause vehicle chassis vibrations that can travel into the passenger compartment of a vehicle, where the vibrations can often times be both felt and heard.

Excessive Engine Rattling

Engine rattling is another common symptom of bad motor mounts. Depending on how many motor mounts are bad, an engine can shake and shimmy in an odd manner, sometimes even bumping against neighboring mechanical parts, all of which can cause engine rattling. Engine rattling due to bad motor mounts is usually more pronounced during times of engine idling. Engine power at this point is low, and an engine is allowed to rock back and forth under normal power, when engine rattling is more easily discerned than under heavy engine power or heavy acceleration.

Abnormal Engine Position

An engine that appears lopsided or out of alignment, relative to its normal position, is normally an engine with broken or severely damaged motor mounts. In addition to securing an engine within the vehicle hood compartment and stabilizing its movements, motor mounts serve to keep an engine aligned and positioned properly to allow for adequate engine operation, and adequate operation of all of the supporting mechanical devices underneath a car's hood. Bad motor mounts can allow an engine to sag or tilt, a situation that is easily spotted by a diligent individual.

Engine Damage

In rare cases, broken motor mounts can cause damage to various engine parts, such as to the exhaust manifold or the valve cover gaskets, both of which are located on the lateral aspect of a vehicle engine. Severely broken motor mounts can allow a vehicle's engine to shift and turn violently, especially during rapid engine acceleration, and/or during high speed driving. This can cause physical damage if the engine turns far enough to one side to allow contact between the engine and the sides of the vehicle engine compartment. Engine parts can become cracked, broken or dented as the result of broken motor mounts.

Broken Engine Belts and/or Hoses

In addition to causing damage to vital engine components, broken motor mounts can also cause damage to various engine drive belts and engine hoses. Severely damaged or broken motor mounts can cause engine belts and hoses to break and/or snap if the engine is allowed to rotate or turn excessively. Belts and hoses, especially water pump and power steering belts and radiator hoses, can be stretched abnormally and severely damaged or broken. As is the case with damage to engine parts caused by bad motor mounts, broken engine belts and hoses are rare occurrences that only happen as the result of severely broken or damaged engine motor mounts.

About the Author

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