A motor mount or engine mount is designed to attach the car engine to the frame of the car itself. Mounts are usually made of rubber and metal. The rubber is used to keep the engine shake from causing the car to shake and the metal connects the engine to the vehicle frame. The purpose of all engine mounts is the same and the number of motor mounts varies depending on the car. Motor mounts can eventually become damaged or break. If your car's motor mounts are bad, you will have several definite signs and symptoms.
Strange Engine Sounds
Start your engine and let it run for a few minutes. Rev the engine and listen closely. Do you feel excessive vibration? If a motor mount is unstable or broken, the engine will move around and create vibration that you may feel and hear while inside the vehicle.
When the engine is idling, listen for rattling. Motor mounts are present to stabilise the engine and keep it from moving freely under the hood. If the motor mount is bad, the engine will move, bumping other parts in the process, creating a knocking or rattling sound.
Visual Differences in Engine Alignment
Pop the bonnet and see if the engine looks out of alignment. If it looks even the least bit different from its normal position, this could be caused by a broken or damaged motor mount. The motor mount is designed to keep the engine aligned to allow for proper operation and adequate operation of every part beneath the hood. A tilting or sagging engine is a sign of a damaged or broken motor mount.
Damage and Leaks to Other Mechanical Parts
If your exhaust manifold or valve cover gaskets are damaged, this could be a sign of a damaged motor mount. In rare cases, broken motor mounts can cause serious damage to engine parts on the side of the engine. While accelerating, the engine moves from side to side and parts may become cracked, broken or dented in the process.
Take a look at engine drive belts and hoses. Motor mounts that are damaged, in bad shape or broken can stretch the hoses or belts and even cause them to break or snap if the engine rotates excessively. Check the water pump and power steering belts as well as the radiator hoses.
Look for exhaust leaks. Check where the head pipe joins the manifold. If there is a leak here, this could be a sign of a damaged motor mount. Sometimes, the head pipe itself will fail if the motor mount is damaged, broken or in need of replacement.