WINDOW AS-DOOR 2119050 - Caterpillar

Pressurized air can cause personal injury. When pressurized air is used for cleaning, wear a protective face shield, protective clothing, and protective shoes.
Debris may have collected near the spark plug. Thoroughly remove any debris. Use compressed air. The maximum air pressure for cleaning purposes must be below 207 kPa (30 psi). Ensure that the area around the spark plug is clean and free of dirt and debris.
Use a 4C-4601 Spark Plug Socket and an extension to loosen spark plug (6). After the spark plug has been loosened, remove the spark plug by hand to detect problems with the threads. After the spark plug has been removed, discard the used gasket.
The use of a thread tap will remove metal unnecessarily. This will also reduce the heat transfer for the spark plug. This can result in a reduction of the spark plug service life and a reduction of the detonation margin.
If the spark plug resists removal by hand, apply penetrating oil to the threads. Use the wrench and apply steady pressure to the spark plug until the spark plug is loose.If the spark plug cannot be removed by hand, clean the threads with 9U-7511 Spark Plug Seat Cleaner. This tool scrapes debris from the seat and from the threads.Inspecting the Spark Plug
Illustration 2 g00838300
(1) Terminal post
(2) Insulator
(3) Shell
(4) Gasket
(5) ElectrodeInspect the spark plug closely for damage. The condition of the spark plug can indicate the operating condition of the engine.Terminal post (1) must not move. If the terminal post can be moved by hand, discard the spark plug.Inspect insulator (2) for cracks. If a crack is found, discard the spark plug.Faint marks may extend from shell (3) onto the insulator. The marks may be a result of corona that forms at the top of the shell. The corona develops when a high-voltage potential ionizes the air that surrounds a conductor, which is a normal condition. This condition is not an indication of leakage between the shell and the insulator.Inspect shell (3) for damage. Cracks can be caused by overtightening the spark plug. Overtightening can also loosen the shell. Discard any spark plug that has a shell that is cracked or loose.Inspect electrode (5) for excessive wear. Flat surfaces with sharp edges provide the best conditions for creating a spark. An electrode will become worn from use. The surfaces erode. A higher voltage is required to produce a spark.
Illustration 3 g00760569
(6) Precious metal pads on the electrode and the ground strapCat spark plugs have precious metal pads (6) on the tips of the electrode and the ground strap. This material will gradually erode.Replace the spark plug if the precious metal is worn off.Light brown deposits or beige deposits around the electrode are produced by normal operation. White deposits or gray deposits may be caused by the following substances:
Excessive oil
Use of the wrong oil
A substance that is introduced through the fuel system or the air systemA spark plug can operate despite a buildup of ash. However, a buildup of ash can cover