VIDEO: Inspecting Spark Plug Appearance

The electrodes and porcelain of a spark plug can reveal short- and long-term problems if you know where to look. OEMs consider the spark plugs a part of the emissions system on most modern vehicles.

Oil fouling of a spark plug typically results in a shiny, black appearance. If enough oil is in the combustion chamber, the deposits can build up on the tip, porcelain or shell.

If you can’t determine if it is carbon or oil fouling, smell the plug; it will smell like engine oil. The oil can come from the piston rings, valve stem seals or the positive crankcase ventilation (PCV) system.

Malfunctioning PCV systems are becoming a leading cause of oil fouling in modern engines. These systems have become more than just a spring-loaded check valve. Modern systems can separate oil from the crankcase vapors and electronically regulate when the engine ingests the vapors. If the PCV valve is stuck open, the excess vapors and oil droplets can quickly foul the spark plugs.

This video is sponsored by Autolite.

When a vehicle owner needs a replacement belt or hose, it's rarely a planned transaction. Motors who only need a belt or hose have likely experienced an unexpected breakdown. While that might be tempting for your DIFM customer to replace the failed part and quickly send the customer on their way, it's a prime opportunity for counter professionals to encourage shops to take a system approach D parts replacement. Let's talk about the serpentine belt. Most vehicle owners know that a noisy belt means something might be wrong, but they probably don't know that replacing the belt rarely stops the noise on its own. That's because the serpentine belt is part of a system of interrelated parts that all need to be in working order for the system to function properly. The serpentine belt, also known as the accessory belt, drives the alternator, that power steering pump, the air conditioning compressor, and sometimes the water pump via the crank shaft.