The main aspects you'll need to check under the bonnet include the engine coolant reservoir, the engine oil level, the brake fluid reservoir and the windscreen washer fluid level.
The Oil Filler Cap
Older engines produce more hot spots, which make the car smoking under hood but not overheating. Worn out piston rings and clogged PCV tube or valve are the culprits that cause this smoking issue.The crankcase ventilation is supposed to pull the smoke back into the engine for burning again.
Generally I do open the bonnet in every 15 days and do dust cleaning as well followed by sanitary checks such as Engine and Brake oil level, coolant level, windscreen fluid etc.
If you let your car overheat and keep driving, the cylinder heads will eventually begin to warp. When this happens, it can lead to a blown head gasket, which would require a lengthy and expensive repair. It also conflicts with the combustion process as the heads do not perform as well when they are warped.
typically takes a solid 30 minutes for an engine to cool down enough for it to be safe to handle. If you'd rather let a professional handle the problem, it's time to call for a tow truck. Once the engine has cooled, check the coolant tank. It's usually a translucent plastic tank near the radiator.