Start the car with your “observer” standing outside the rear of the vehicle. The car should start easily, and on the first try. If there is excessive smoke, vibration, or the car idles improperly (too slow or rough), something is mechanically wrong.
Engines operate differently when cold – this is normal. To bring them to operating temperatures more quickly (a vehicle at operating temperature spews fewer emissions into the atmosphere), engineers have designed them to run faster at idle for the first minute or two.
The goal is to drive the vehicle long enough to bring it up to full operating temperature (at least ten minutes) and then continue driving for at least several minutes. This is the only way to properly test the cooling system of the vehicle.
With an automatic transmission, it should shift out of “Park” easily. When “Reverse” or “Drive” is engaged, be aware of any sudden jolts that may indicate possible transmission problems. A manual transmission vehicle should go into “Reverse” without any grinding.
While driving, an automatic transmission should shift smoothly through the gears, while a manual transmission should shift effortlessly without grinding or unnecessary effort.
Engine and Transmission – Common Observations and their Possible Causes:
- Smoke at start-up (oil leak, bad gaskets, worn engine internals, etc…)
- Squealing noise from under the hood (belt problems, power steering pump failure, bearing issues, etc…)
- Rough idle (fuel injection, carburetor, bad fuel, etc…)
- Grinding into gear (transmission problems, bad clutch, worn synchronizers, etc…)
- High temperature gauge (low coolant, radiator leak, broken electric fan, etc…)
Note:
At the end of the road test, open the hood. Smoke rising from the engine compartment will indicate a hidden oil leak. All engines will "click" as their metal components cool down.
