Why is there a strong odor of exhaust inside car while idling or using heater?

A strong odor of exhaust inside a car while idling or using the heater often indicates a leak in the exhaust system, allowing harmful fumes to enter the cabin. This can occur due to damaged gaskets, cracked exhaust pipes, or issues with the heater core, which may allow exhaust gases to mix with the vehicle's heating system. It's crucial to address this issue promptly, as inhaling exhaust fumes can be dangerous to health. Regular maintenance and inspections can help prevent such problems.