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.
Ask Away! with Jeff Smith: How to Set Preload on Hydraulic Lifters â and Why It's Important! 1  I just installed a new cam in my small block Chevy. The engine runs great, but Iâve noticed that at idle and at some cruising speeds the engine makes a noise that sounds more like a mechanical lifter camshaft.