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.
When the tube is not opening and closing normally it is called Eustachian Tube Dysfunction. This can cause a crackling noise in the ear when you swallow and can even cause some pressure feeling in the ear. The cause of ETD can vary. The most common cause is a sinus infection or allergies. Once these clear, the ETD should clear as well, and the crackling noise should stop.