#### SMELL

Strange odors are often a clue to something gone (or about to go) wrong.

- An overheated radiator gives off a steamy vapor and a mild odor something like burning paint. It should warn you to check the temperature gauge or to stop and check the coolant level.
- Overheated brake linings give off a strong definite odor of something burning. Usually overheated linings are accompanied by squeaking sounds from the wheels, indicating that the linings are glazed from heat. The best thing to do is stop and let the brakes cool for about half an hour, but have the brakes checked as soon as possible.
- Burning oil or grease is a strong, pungent odor, usually more noticeable when the vehicle is not moving. Occasionally, there will be wisps of smoke coming from under the hood. The problem could be as simple as oil leaking from valve cover gaskets onto hot exhaust manifolds, or it could be just accumulated grease from a long overdue engine cleaning.
- A frequent smell associated with catalytic converters is the rotten egg smell, which is unmistakable for anything else. One of the byproducts of the reaction in the catalytic converter is sulfur dioxide (SO2), which is responsible for the odor. It does not necessarily indicate a malfunction, but is extremely unpleasant.

  Fig. 1: Vibration diagnosis charts

  Fig. 2: Noise diagnosis chart