CAB AR 2390118 - Caterpillar

Caterpillar EnginesWhen a cooling system with glycol develops a leak into the oil system, the leak source must be found and repaired. The amount of glycol contamination of the engine lube oil must be determined and the appropriate action taken. Depending on the severity of the coolant leak, the required action will differ.
Customers who use Scheduled Oil Sampling can usually determine leaks at an early stage and can clean the engine lube system with just an oil and filter change. In addition to the positive indication of glycol, the increase in sodium levels in the used oil analysis is another method to define a coolant leak. The supplemental coolant additives contain sodium compounds which will appear as increased sodium in the metal analysis.
Oil analysis can result in one of the four different "Coolant Leak Indications" that follow. There is a different "Clean-Up Procedure" for each one of the "Coolant Leak Indications." The "Coolant Leak Indications" and associated "Clean-Up Procedures" follow:
Coolant Leak Indicator 1
The oil analysis may indicate positive glycol, but the sodium levels do not show any increase. An oil analysis of a sample of the new oil that was used in the engine should be made. Some new oils have additives which will give positive glycol results.
Clean-Up Procedure 1
No coolant leak has occurred and no further action is required.
Coolant Leak Indicator 2
The oil analysis indicates positive glycol and the sodium level in the oil has also increased. Examine the oil filter for any signs of metal particles or heavy residue on the filter surface. If none exist, repair the source of the leak.
Clean-Up Procedure 2
Change the oil and filter. No other clean-up is required since the amount of coolant in the oil was limited. But, continue to check the oil filter for any residue or metal particles at 50 hour intervals during the next oil change period to be sure the problem has been corrected.
Coolant Leak Indicator 3
The oil analysis indicates positive glycol and the sodium level in the oil has also increased. Some water in the oil may also be noted. The oil and the filter now indicate a heavy, tacky, black or gray residue, but no sign of metal particles are evident. Customers who do not do oil analysis will usually find the coolant leak in this manner. This is a situation where coolant has leaked into the engine oil.
Clean-Up Procedure 3
a. Find and repair the coolant leak.b. Drain the oil and install new filters. Fill the engine crankcase with a mixture of 75% API CF-4 SAE 15W40 oil and 25% butyl cellosolve. Do not mix more than the 25% butyl cellosolve or use a lower viscosity oil. The resulting mixture viscosity will be too low to provide proper lubrication. Butyl cellosolve is a strong liquid solvent and extreme care should be used when handling it. Keep it off of your hands because it can cause skin injuries. Butyl cellosolve will damage any finished surfaces. In the event of spillage, flush the area with clean