2002 Mazda
7 Answers
A bad knock from the lower end can be from a rod or main bearing. That's when an engine has to be rebuilt or scrapped. Knocking or tapping from the upper end (the heads) can be from valves or lifters or cam bearings, still can be an expensive fix but slightly less than the cost of replacing the motor. Timing chains also make noise, not so much a knock as a tick or slapping. Still an expensive fix but less then the above. An oil pump can also make noise before failing. Without an actual hands-on inspection it's impossible to make suggestions to you.
Have you even thought about checking the engine oil level???
I dont know about cars. Im learning. This is my first car
