What are the effects of oil leakage from spark plugs?
2 Answers
The effect of oil leakage from spark plugs is poor ignition, causing the engine to malfunction. Steps to replace spark plugs: Open the hood, lift the engine's plastic cover, remove the high-voltage distributor wires, and mark each cylinder's position to avoid confusion. Use a spark plug socket to remove the spark plugs one by one. When removing them, check for external debris like leaves or dust and ensure they are cleaned thoroughly. Place the new spark plug into the spark plug hole, hand-tighten it a few turns, and then use the socket to tighten it further. Reinstall the removed high-voltage distributor wires in the firing order, then secure the cover. Methods to determine if a spark plug is damaged: Remove the spark plug and observe its condition based on the following appearance characteristics. A normal spark plug's insulator skirt and electrodes appear gray-white, gray-yellow, or light brown. A properly functioning spark plug has a reddish-brown insulator skirt, with an electrode gap between 0.8-0.9mm and no signs of electrode burn. If the spark plug is oily or has deposits but is not damaged, it can continue to be used after cleaning off the oil and deposits. If the spark plug is severely damaged—showing signs like blistering, black streaks, cracks, or melted electrodes—identify the cause of the damage, fix the issue, and replace the spark plug. Additionally, if the spark plug appears blackened as if smoked, it indicates incorrect heat range selection, a rich fuel mixture, or oil leakage.
As someone who has been repairing cars for over a decade, I've seen too many cases of spark plug oil leaks. The most direct effects are difficulty starting the car, sluggish acceleration, and abnormally high fuel consumption. Oil seeping into the spark plug wells contaminates the electrodes, and when sparking, the spark is enveloped by the oil film, making ignition impossible. Ignoring this long-term leads to bigger troubles—high-temperature engine oil can corrode the rubber boots of the ignition coils, and replacing a set of coils costs as much as half a tire. Last week, an old Tiguan had a leaking valve cover gasket, causing the spark plugs to soak in oil, resulting in cylinder misfires and engine shaking. The issue was resolved by removing the aluminum top cover of the engine and resealing it. If you see oil stains on the spark plug threads, don't hesitate—get it fixed immediately.
