You are driving along, no worries in the world, and suddenly there is a strange noise coming from under the hood. You open the hood and stare at the engine, without any idea where the noise is coming from and want to figure out what the noise means. Engine noises need not be frightening. Sometimes they do indicate a serious problem, but before calling a roadside mechanic for an expensive repair, there are a few troubleshooting options you can run through on your own.
Check the level of oil in the vehicle if you hear a tapping or clicking sound coming from the engine. If the oil is low, bring the level up to normal. Check the oil filter for excessive clogging and replace if necessary.
Check the timing belt if you hear a rattling sound coming from the engine. Take off the timing belt cover and inspect the components with a flashlight for any parts failure. Make sure that the belt is secure. If it is damaged, have it replaced.
Check for air in the brake system if you hear a popping of bubbling sound from the engine. Make sure there is enough brake fluid in the cylinder. Fill the cylinder if the fluid is low. Air can get into the system if the fluid is too low. Check the hoses and brake system for any holes or leaks.
Check for worn rod bearings if you hear a deep knocking sound coming from the engine. If this is the case, you may need to have your engine rebuilt or replaced.
Check the starter motor if you hear a scraping sound coming from the engine. The starter motor cranks the engine and there is a sound associated with this, however if the scraping noise continues after the engine is running, it could mean that the starter motor has failed and may have to be replaced.
Check the magnetic clutch on the a/c compressor if you hear a scraping sound. Turn the air conditioner on and listen for the magnetic clutch to engage. If you hear a scraping sound connected to turning the a/c on, it could mean that the compressor needs to be replaced. Check to see if the scraping sound stops when you turn the a/c off. This should alert you to whether or not it is actually the a/c compressor that is the problem.
Check the radiator coolant level if you hear a popping sound coming from the engine. Never open the radiator cap when it is hot. Wait for the engine to cool before filling the radiator with a 50/50 mix of coolant and distilled water. Make sure the coolant reservoir tank is filled as well. Check for any hoses that are pinched of damaged. Replace the radiator cap if necessary.
