CONTROL GP-HYDRAULIC HAND 3898124 - Caterpillar

Introduction
Use the solution that is identified below as a remedy for the problem with the cooling system.Problem
The machines that are mentioned above may exhibit the formation of green sludge and red sludge in the cooling system.Green Sludge
Caterpillar Extended Life Coolant (ELC) contains a number of corrosion inhibitors. One of the inhibitors in ELC is Tolytriazo (TT). TT is a copper corrosion inhibitor that reacts with copper to form a green protective coating. This coating prevents the oxidation of copper. If this reaction occurs in excess, a green material (sludge) will be produced. This sludge can cause the clogging of the radiator cores and may result in overheating. The conditions below can cause green sludge to form:
The Low TT level caused by not adding Cat Extender at the proper interval. When the TT level gets low, the consumption of TT can occur at a rapid rate.
Erosion of the copper/TT can occur if abrasive particles in the coolant. These abrasive particles can cause the copper/TT coating to be removed and increase the copper oxidation (corrosion).
A stray electrical current can cause copper or other similar metals to produce the erosion that is mentioned above.Red Sludge
Another issue is the formation of red or brown sludge. This formation can occur when air pockets exist in the cooling system or when the coolant level is low. Iron components that are exposed to the air will rust. The rust inhibitor in ELC will combine with the rust and will form iron carboxylates. An excess of this reaction will result in a red or brown sludge and cause overheating. A stray electrical current can contribute to this problem.Solution
The Operation and Maintenance Manual gives instructions that pertain to this area:
Level II coolant analysis should be completed after the first 500 hours and on an annual basis thereafter.
Cat Extender should be added at 6000 hours.
If Cat Extender is not added at 6000 hours, then the ELC should be replaced.Note: If TT levels drop below 300 ppm in less than 1 yr, it is possible that erosion, corrosion, or a stray current is occurring. The cooling system may need to kidney loop filter the coolant in order to remove the sludge. In order to remove sludge, the system must be drained and the cooling system must be flushed. Refill the system. Note: Conditions may indicate that the radiator core is plugged. These symptoms can include overheating of the machine or the coolant may have a burnt odor. In this event, 4C-4611 Cooling System Cleaner should be used. Drain the cooling system and flush the cooling system. Use new ELC to refill the cooling system.