Explain the Motor Mounts on PT Cruisers

by Hunkar Ozyasar

In every modern vehicle, the engine is attached to the chassis (the body) of the vehicle with motor mounts. If automakers were to simply tighten an engine onto the vehicle with nuts and bolts, the vibrations produced by the engine would cause a very uncomfortable sensation inside the vehicle. To reduce undue vibrations, the motor mounts are made out of steel and rubber and act as springs.The PT Cruiser has three motor mounts.

Purpose

Every gas- or diesel-powered engine shakes as it generates power. This is a natural result of many parts moving violently in response to controlled explosions inside the cylinders. If the engine were bolted directly to the chassis of the vehicle, these vibrations would be felt inside the cabin, leading to serious discomfort. Excessive vibrations also cause mechanical failure of the transmission, steering and suspension, as these parts too do not like to be shaken. The purpose of motor mounts is to dampen these vibrations and to transmit to the rest of the vehicle as little of them of them as possible.

Function

Motor mounts dampen the vibrations of the engine by acting like springs. However, the mounts must have very little movement, since a heavy mass moving around a lot in the middle of the car will significantly disturb the vehicle's balance. Due to this reason, they do not really look like springs, but tiny arms. Their appearance as well as function is much like the suspension arms that connect the tires to the rest of the car.

PT Cruiser Mounts

The engine in the PT Cruiser is held in place by three motor mounts. These mounts have a rubber core encased in steel and are quite small. The dampening of the vibrations is due to both the shape of the unit as a whole (much like an arm), which allows the engine to oscillate, and the rubber, which further soaks up the residual vibrations. The mount is fixed to the chassis on one end, while the free floating end (the tip of the arm) is attached to the engine.

Cheap and Simple

If you were to get under the car and look at the PT Cruiser's motor mounts, you would be surprised at how small and simple those mounts are. They are very cheap too, costing around $20 to $30 apiece. An entire set comes out to less than $100.

Failure

Although motor mounts do not fail frequently, you should get them checked if you suspect that one or more of them are no longer functioning optimally. Failures are often due to excessively dry conditions, leading to cracks in the rubber or oil leaks from the engine, which also harm the rubber core over the long term. The most important symptom is, as you have probably guessed, excess vibration of the vehicle. Another symptom is unusual shaking of the engine. Get your car checked right away if you encounter any of these issues.

About the Author

Hunkar Ozyasar is the former high-yield bond strategist for Deutsche Bank. He has been quoted in publications including "Financial Times" and the "Wall Street Journal." His book, "When Time Management Fails," is published in 12 countries while Ozyasar’s finance articles are featured on Nikkei, Japan’s premier financial news service. He holds a Master of Business Administration from Kellogg Graduate School.

Photo Credits

  • photo_camera engine image by goce risteski from Fotolia.com