975687 Volvo.Penta O-ring

Personal injury can result from escaping fluid under pressure.If a pressure indication is shown on the indicator, push the release valve in order to relieve pressure before removing any hose from the radiator.
Check the coolant level in the cooling system. Refer to Operation and Maintenance Manual, "Cooling System Coolant Level - Check". If the coolant level is too low, air will get into the cooling system. Air in the cooling system will cause a reduction in coolant flow and bubbles in the coolant. Air bubbles cause a reduction in the cooling of engine parts.
Check the radiator.
Check the radiator for a restriction to coolant flow. Check the radiator for debris, for dirt, or for deposits on the inside of the radiator core. Debris, dirt, or deposits will restrict the flow of coolant through the radiator.
Check for debris or for damage between the fins of the radiator core. Debris between the fins of the radiator core restricts air flow through the radiator core. Refer to Testing and Adjusting, "Cooling System - Inspect".
Check for missing radiator baffles or for damaged radiator baffles. Radiator baffles prevent recirculation of air around the sides of the radiator. A missing radiator baffle or a damaged radiator baffle raises the temperature of the air that goes through the radiator.
Ensure that the radiator size is according to the OEM specifications. An undersized radiator does not have enough area for the effective release of heat. This undersized radiator may cause the engine to run at a temperature that is higher than normal. The normal temperature is dependent on the ambient temperature.
Check the quality of the coolant. The coolant should have the following properties:
Color that is similar to new coolant
Odor that is similar to new coolant
Free from dirt and debrisIf the coolant does not have these properties, drain the system and flush the system. Refill the cooling system with the correct mixture of water, antifreeze, and coolant conditioner. Refer to Operation and Maintenance Manual, "General Coolant Information".
Check the coolant mixture of antifreeze and water. The mixture should be approximately 50 percent water and 50 percent antifreeze with 3 to 6 percent coolant conditioner. Refer to Operation and Maintenance Manual, "General Coolant Information". If the coolant mixture is incorrect, drain the cooling system and flush the cooling system. Refill the cooling system with the correct mixture of water, antifreeze, and coolant conditioner.
Check for air in the cooling system. Air can enter the cooling system in different ways. The following items are some of the most common causes for air in the cooling system:
Filling the cooling system incorrectly
Combustion gas leakage into the cooling system
Loose hose clampCombustion gas can get into the system through the following conditions: inside cracks, damaged cylinder head and damaged cylinder head gasket. A loose hose clamp can allow air into the cooling system during the cooldown period. Air in the cooling system causes a reduction in the cooling capacity of the coolant.
Check the fan drive system. A fan drive system that is not turning at the correct speed can cause improper air speed across the radiator core. The lack of proper air flow across the radiator core can cause the coolant not to cool to the proper temperature differential.
Check the water temperature gauge. A water temperature gauge which does not work correctly will not show the correct temperature. Refer to Testing and Adjusting, "Cooling System - Test".
Check the sending unit. In some conditions, the temperature sensor in the engine sends signals to a sending unit. The sending unit converts these signals to an electrical impulse which is used by a mounted gauge. If the sending unit malfunctions, the gauge can show an incorrect reading. Also if the electric wire breaks or if the electric wire shorts out, the gauge can show an incorrect reading.
Check the filler cap. A pressure drop in the radiator can cause the boiling point to be lower. This pressure drop can cause the cooling system to boil. Refer to Testing and Adjusting, "Cooling System - Test".
Check the fan and/or the fan shroud.
Ensure that the fan is installed correctly. Improper installation of the fan can cause engine overheating.
The fan must be large enough to send air through most of the area of the radiator core. Ensure that the size of the fan and the position of the fan are according to the OEM specifications.
The fan shroud and the radiator baffling must be the proper size. The fan shroud and the radiator baffling must be positioned correctly. The size of the fan shroud and the position of the fan shroud should meet the OEM specifications. The size of the radiator baffling and the position of the radiator baffling should meet the OEM specifications.
Check the cooling system hoses and clamps. Damaged hoses with leaks can normally be seen. Hoses that have no visual leaks can soften during operation. The soft areas of the hose can become kinked or crushed during operation. These areas of the hose can cause a restriction in the coolant flow. Hoses can become soft. Also, hoses can get cracks after a time. The inside of a hose can deteriorate, and the loose particles of the hose can cause a restriction of the coolant flow. Refer to Operation and Maintenance Manual, "Hoses and Clamps - Inspect/Replace".
Check for a restriction in the air inlet system. A restriction of the air that is coming into the engine can cause high cylinder temperatures. High cylinder temperatures can cause higher than normal temperatures in the cooling system. Refer to Testing and Adjusting, "Air Inlet and Exhaust System - Inspect".
If the measured restriction is higher than the maximum permissible restriction, remove the foreign material from the engine air cleaner element. Install a new engine air cleaner element if the foreign material cannot be removed. Refer to Operation and Maintenance Manual, "Engine Air Cleaner Element - Clean/Replace".
Check the air inlet system for a restriction again.
If the measured restriction is still higher than the maximum permissible restriction, check the air inlet piping for a restriction.
Check for a restriction in the