CYL GP-HYD 3969840 - Caterpillar

Procedure to Clean Cooler Core Before Repair Is Made.
Remove all paint, oil, grease or dirt from the area that needs repair. A small knife, file, emery paper, wire brush and/or solvent can be used.
Do not use a cleaner that will cause a chemical reaction with aluminum. These types of cleaners will damage the core.
Trichlorethylene or chlorothene nu can be used as solvents to clean the cooler core. Flush the internal part of the cooler core with a solvent. If the area to be repaired is very small the internal parts can be cleaned by pushing either acetone or carbon tetrachloride through the hole.
Weld Procedure
Use 4043 welding rod and tungsten inert gas welding process. Any part of the cooler core can be repaired with this procedure, but it is normally easier to weld on the heavier sections of the cooler core.
Epoxy Procedure
Use a two part epoxy such as Devcon Special-F Repair Kit-aluminum filled, Devcon EK-4 Kit-unfilled, or an equivalent epoxy.
Do not mix the epoxy until the cooler core is ready for the repair. If additional parts such as a screw or a screen are needed to make the repair, be sure that you have those parts ready. Do not mix more of the epoxy than is needed to make the repair.The epoxy in The Special-F Repair Kit has a cure time (amount of time needed for the epoxy to completely dry) of approximately 8 hours and a pot life (amount of time that epoxy can be used after it is mixed) of approximately 20 to 30 minutes. This type of epoxy is normally used on larger repairs.
The epoxy in the EK-4 Kit will set (become rigid but not completely hard) in approximately 15 minutes or it has a cure time of approximately 20 minutes when a 100 Watt light bulb is used to give heat to the epoxy. The epoxy in the EK-4 Kit has a pot life of approximately 5 to 6 minutes. This type of epoxy is normally used on smaller repairs.
The epoxy will take longer to dry if the temperature is less than 65°F (18°C). A 100 Watt light bulb can be used to make the epoxy dry faster if the temperature is below 65°F (18°C).
Mix equal amounts of each part of the epoxy on a surface that can be thrown away such as a piece of wood or a heavy cardboard. Use a putty knife or spatula to mix the two parts thoroughly. Immediately put the epoxy on the area to be repaired.
If the area is small, it can be repaired by pushing the epoxy into the hole so some of the epoxy goes into the core. Then put epoxy over the hole and the