at what mileage should spark plugs be changed
Removing and inspecting spark plugs tell you a lot about how well the engine is running and what may be causing problems. All spark plugs should be removed and checked every 30,000 miles - even if your BMW is low maintenance - you're told to change spark plugs at 100,000 miles. This prevents the plugs from seizing in the block, causing expensive repairs down the road. Always note which plug came from which cylinder.