It’s best to follow your regular maintenance schedule. But here are some ways your car might tell you it’s ready for an oil and filter change:
-Your dashboard oil reminder: In newer vehicles, this light or text message takes your actual driving conditions into account.
-Dark oil on your dipstick: Fresh engine oil is transparent and light brown or amber. Dirty oil is dark brown or black -- and too opaque to see through.
-Overheating: Poor lubrication also makes your engine work harder, which can generate excess heat.
-Grinding or tapping noises: these may be the dreaded “metal on metal” sounds, warning you that your oil level is too low to protect your engine.