Why does my Toyota Hilux's engine constantly overheat?

I recently bought a used Toyota Hilux and have been experiencing issues with the engine overheating. I've noticed that the temperature gauge goes all the way to the red zone and then drops back down before going back up again. What could be causing this and how can I fix it?

It's possible that your cooling system is not functioning properly. Check your radiator and hoses for any leaks or damage. Also, make sure your coolant levels are at the recommended level.

Another possible cause could be a faulty thermostat. If it's not opening and closing properly, it can lead to overheating. Consider getting it checked and replaced if necessary.

It's also important to check your oil levels and make sure they are at the recommended level. Low oil levels can cause your engine to overheat.