My father recently bought a Volkswagen Polo which is a very affordable and powerful car but it's engine makes to much of sound, it sounds like the car has not been serviced since a year. I am doing diploma in automobile engineering and have a little knowledge about the automotive industries.
There are few reasons because of which the engine sounds bad. This sound is probably know as TAPPET or upper valvetrain noise. There are many other engine noises like the engine bearing noise, collapsed lifter noise, engine valve noise, etc. The reason for such sounds are mentioned below:
• Low oil pressure.
• Detonation or spark knock.
• Lose torque converter bolts.
• Cracked flywheel( automatic transmission)
• Excessive connecting rod or main bearing clearance.
• Excessive piston clearance.
• Tips to avoid such engine noise problems in the Volkswagen Polo.
• Change the engine oil regularly from time to time
• Don't drive the car rashly.
• Change the gears of the car only after touching the rev limit.
• Do not perform stunts with your car.