Hello Doreen, a low rumbling sound when driving over 80 KPH should not be ignored, even if the car appears to be running normally. Here are some potential factors that may cause this noise on the highway:
1. Worn wheel bearings: When a wheel bearing is worn out, it can produce a low growling or humming noise. This noise may become more pronounced as you drive faster or when you take corners, due to the weight shifting to the affected side of the tyre.
2. Unevenly worn tyres: Tyres that are unevenly worn, especially those exhibiting feathering, cupping, or separated belts, can also generate a growling noise that intensifies at higher speeds.
3. Wheel alignment issues: Poor wheel alignment can lead to unusual tyre wear, resulting in a rumbling noise.
4. Drivetrain problems: In four-wheel-drive or rear-wheel-drive vehicles, damaged propeller shaft bearings, universal joints, or differential bearings can also cause a low rumbling sound.
It is important to address these issues promptly to ensure your vehicle’s safety and performance.