THERMOSTAT AS 1533275 - Caterpillar

(4KG, 1SK) MARINE ENGINES AND 3114 (5EF) INDUSTRIAL ENGINES EQUIPPED WITH A 7C-6999 SEA WATER HEAT EXCHANGER GROUPProblem:
Some of the above engines have experienced unexplained engine coolant loss. Investigation of the 7C-6999 Sea Water Heat Exchanger Group on these engines revealed the 6V-5504 O-Ring Seal had been rolled or damaged during the assembly process. See the illustration. The 6V-5505 O-Ring Seal installed in the 7W-1185 Bonnet located on the right side of the 7C-6999 Sea Water Heat Exchanger Group. This seal has engine coolant on one side and sea water on the other. If the seal is damaged on not correctly located, engine coolant can be lost into the sea water side of the cooling systemInvestigation revealed a substitute O-ring seal lubricant was used instead of the specified 1U-6395 O-Ring Compound. The substitute lubricant contributed to the O-ring rolling and damage.Solution:
The factory is again using the specified 1U-6395 O-Ring Compound during the assembly of the heat exchanger and each heat exchanger is pressure tested after it is assembled.If unexplained engine coolant loss is encountered, a damaged or incorrectly located 6V-5504 O-Ring Seal should be suspected, even though there are several conditions that can cause loss of engine coolant.To check the heat exchanger for a damaged or incorrectly located 6V-5504 O-Ring Seal,use the 9S-8140 Pressurizing Pump Group to pressurize the engine coolant system expansion tank with to 34 kPa (5 psi). If a pressure drop is observed, inspect and replace the 6V-5504 O-Ring Seal if needed. Put a light coating of 1U-6395 O-Ring Compound on the 6V-5504 O-Ring Seal before installing the seal.
LOCATION OF 6V-5504 O-RING SEAL IN 7C-6999 SEA WATER HEAT EXCHANGER GROUPCOPYRIGHT 1994 CATERPILLAR ALL RIGHTS RESERVED