You may be surprÂ­ised to discover that a carbon monoxide (CO) detector really isn't a complicated piece of equipment. Housed inside a plastic chamber approximately 3 inches (7.6 centimeters) in diameter are parts that work in unison to alert a househoÂ­ld when lethal gas is detected.
This type of noise is usually caused by malfunctioning valve lifters or an exhaust manifold leak. If the noise lasts for more than a minute and completely disappears or dimishes after the engine is warm, the most likely cause is an exhaust manifold leak.
Whenever a vehicle owner complains of under-the-bonnet noise, it is important to determine the type of noise and under what circumstances it occurs. A solution to a noise problem caused by pulley misalignment is not likely to resolve a slip noise problem that may be caused by insufficient tension. In any case, a noisy drive indicates a malfunction, and appropriate corrective action should be taken to eliminate the problem. Belt noise.