I have two cracked motor mounts on my KIA Sadona. I am curious as to what may have caused this. I am wondering if driving longer distances could cause it to happen

It is a 2004 Kia Sedona EX. I bought it in April.

  • What is the year of your vehicle? – DucatiKiller Dec 2 '15 at 23:01

The main thing which damages motor mounts is the torque provided by the engine (the twisting motion the motor mounts are preventing). When you are driving down the highway on a long cruise, you are actually putting less torque the motor mounts than you would if you were in stop & go traffic. Any motion causes wear on your motor mounts, but highway driving is going to cause the least amount of wear on them when compared to other types of driving.


A few factors contribute to rubber inserts within motor mounts to fail.

1. Dry Rot

The rubber decays over time and loses it's elasticity. The degraded rubber fails slowly over time.

2. Chemicals

Some chemicals can accelerate the decay of rubber. Certain acids such as hydrofluoric and hydrochloric will degrade Buna-N rubber. EPDM rubber can degrade from gasoline or glycol ethers contained in brake fluid.

3. Physical

Shifting from park to reverse then to drive does the most physical wear.

Add the three together and considering you have a 2004 vehicle it's completely reasonable that you've had a failure.

Highway driving is probably better than the car just sitting as the motion and input help to keep the rubber pliable for longer. Counter intuitive.

Replace it and good luck!

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.