955780 Volvo.Penta Hexagon nut

Cooling System
Make sure you read and understand the information in the Safety and Cooling System Specifications sections of this manual before you proceed with cooling system maintenance.
Add Extender (Long Life Coolant/Antifreeze Only)
Extender should be added to LLCA after 3,000 service hours or two years, whichever comes first. The cooling system should be treated with .95 L (1 qt) of Extender for every 46 L (12 US gal) of cooling system capacity.For more Extender information, refer to the Cooling System Specifications LLCA Extender topic in this manual.Drain/Clean/Replace Coolant (Conventional Coolant/Antifreeze Only)
Do not perform this maintenance until you read and understand the material in the Safety and Cooling System Specifications sections of this publication.
Clean/Flush the cooling system before the recommended maintenance interval if:* Coolant is heavily contaminated.* The engine overheats frequently.* Foaming is observed in the radiator.* The oil cooler has failed, allowing oil to contaminate the coolant.
Use of commercially available cooling system cleaners may cause damage to cooling system components. Use only cooling system cleaners that are approved for Caterpillar engines.
A good time to replace the thermostat and hoses is when your engine's cooling system has been drained.Drain
1. Stop the engine and allow the engine to cool. Loosen the coolant filler cap slowly to relieve any pressure, and remove the cap.2. Open the radiator drain valve. Remove the block and oil cooler drain plugs. Remove the drain plug from the bottom of the water pump housing. Allow the coolant to drain.
Dispose of used engine coolant properly or recycle. Various methods have been proposed to reclaim used coolant reuse in engine cooling systems. The full distillation procedure is the only method acceptable by Caterpillar to reclaim the used coolant.For information regarding disposal and recycling of used coolant:
Contact Caterpillar Service Technology Group:Outside Illinois: 1-800-542-TOOLInside Illinois: 1-800-541-TOOLCanada: 1-800-523-TOOLClean
3. Flush the cooling system with clean water to remove any debris.4. Clean and install all drain plugs and/or close the drain valve(s).
Fill the cooling system no faster than (19 L) (5 US gal) per minute to avoid air locks.
5. Fill the cooling system with a mixture of clean water and Caterpillar Fast Acting Cooling System Cleaner. Add .5 L (1 pt) of Cleaner per 15 L (4 US gal) of cooling system capacity. Install the radiator filler cap.6. Start and run the engine for a minimum of 30 minutes with the coolant temperature at 82°C (180°F). Stop the engine and allow the engine to cool.7. Loosen the filler cap slowly to relieve any pressure, and remove the cap. Remove the cooling system drain plug(s) or open the drain valve(s). Allow the cleaning solution to drain. Flush the cooling system with clean water until the draining water is clear. Clean and install all drain plugs and/or close the drain valve(s).Fill
Refer to the Cooling System Specifications for all information regarding acceptable water, coolant/antifreeze, and supplemental coolant additive requirements. Refer to the Refill Capacities chart in this publication for the capacity of your engine's system.8. Fill the system with recommended coolant/antifreeze mixture.9. Start and run the engine with the filler cap removed. Allow the coolant to warm, the thermostat to open and the coolant level to stabilize. Check the coolant level. Add coolant mixture if necessary to bring the coolant to within 13 mm (1/2 in) below the bottom of the fill tube or the correct level on the sight glass (if equipped)10. Check the condition of the filler cap gasket. If the gasket is damaged, discard the old filler cap and install a new filler cap. If the gasket is not damaged, use a 9S8140 Service Tool (available from your Caterpillar dealer) to pressure test the filler cap. The correct filler cap pressure is stamped on the face of the filler cap. If the filler cap does not hold the correct pressure, install a new filler cap.11. Start the engine and inspect for coolant leaks and proper operating temperature. Check for coolant leaks.Cooling Systems with Heavy Deposits or Plugging
For the following procedure to be effective, there must be some active flow through the radiator and the other cooling system components.Follow the same steps as outlined above, with the following modifications to steps 5 and 6:5. Fill the cooling system with a mixture of clean water and Caterpillar Fast Acting Cooling System Cleaner. Add .5 L (1 pt) of Cleaner per 3.8 to 7.6 L (1 to 2 US gal) of cooling system capacity. Install the radiator filler cap.6. Start and run the engine for a minimum of 90 minutes with the coolant temperature at 82°C (180°F). Stop the engine and allow the engine to cool.Replace Thermostat, Gasket and Seal
If replacing the thermostat ONLY, drain the coolant from the cooling system to a level below the thermostat housing.Refer to the Disassembly and Assembly procedure in the Service Manual or contact your Caterpillar dealer to perform the following maintenance.
(1) Thermostat Housing(2) thermostat.1. Stop the engine. Allow the engine to cool. Loosen the radiator filler cap slowly to relieve any pressure, then remove the cap.2. Loosen the hose clamps to disconnect hose assembly from the radiator to thermostat housing assembly (1). Remove the housing.3. Remove thermostat (2) and gasket from the housing. Remove the lip-type seal from the housing.Install Thermostat
If the thermostat is installed wrong, it will cause the engine to overheat.Caterpillar engines incorporate a shunt design cooling system and require operating the engine with a thermostat installed. Depending on load, failure to operate with a thermostat could result in either an overheating or excessive cooling condition.
4. Install a new seal in the housing counter bore seat with the lip of the seal away from the thermostat.5. Install the thermostat in the housing.6. Position a new gasket on the housing. Install the housing.7. Connect the hose assembly and tighten the hose clamps.Turbocharger