Engine Vibration at Idle

The engine in your car is designed to run balanced to minimize vibration to the passengers. Vibration is the most noticeable when the engine is at an idle. Several components are designed to help minimize engine vibration. I have listed some of the most common problems and repairs below.

Troubleshooting Procedure
- Engine mounts are used to minimize engine vibration by isolating the engine from the car frame. These mounts are constructed by using rubber vulcanized between to metal plates with threaded studs that bolt to the engine and the frame of the car. When motor mounts become worn they allow the engine the contact the frame causing a noticeable vibration. Inspect the engine mounts for integrity, look for any oil, cracks or separation of the mount. Remove the failed engine mount and replace if needed. For exact instructions how to replace the engine mounts in your vehicle consult an auto repair manual.


New Engine Mount (appearance will vary)

- A balance shaft belt is used inside some designs of engines to counter act vibration created by the natural engine operation. Many balance shafts are operated by a timing belt
that can break or become out of correlation with the engine either by a worn timing belt or misalignment when replaced. To inspect for this problem, remove the timing belt cover and inspect timing belt marks for proper alignment. All engines are different, consult a car repair manual for exact belt alignment specifications.

- An engine depends on an equal compression reading in each cylinder. If poor compression exits in one or more cylinders it can cause a rough idle condition. To check for this condition perform an engine compression test to compare readings. Once a low cylinder has been detected addition internal engine inspection is required.