865440H70 Mercruiser HOUSING, Driveshaft - Basic, Basic

Illustration 1 g01106438
Boiling point of water
Remember that temperature and pressure work together. When a diagnosis is made of a cooling system problem, temperature and pressure must be checked. Cooling system pressure will have an effect on the cooling system temperature. For an example, refer to Illustration 1. This will show the effect of pressure on the boiling point (steam) of water. This will also show the effect of height above sea level.
Personal injury can result from hot coolant, steam and alkali.At operating temperature, engine coolant is hot and under pressure. The radiator and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns.Remove filler cap slowly to relieve pressure only when engine is stopped and radiator cap is cool enough to touch with your bare hand.Cooling System Conditioner contains alkali. Avoid contact with skin and eyes.
The coolant level must be to the correct level in order to check the coolant system. The engine must be cold and the engine must not be running.After the engine is cool, loosen the pressure cap in order to relieve the pressure out of the cooling system. Then remove the pressure cap.The level of the coolant should not be more than 13 mm (0.5 inch) from the bottom of the filler pipe. If the cooling system is equipped with a sight glass, the coolant should be to the proper level in the sight glass.Tools for Testing the Cooling System
Table 1
Required Tools
Part Number Part Name Quantity
4C-6500 Digital Thermometer 1
285-0910 Multi-Tool Gp 1
9S-8140 Pressurizing Pump 1
9U-7400 Multitach Tool Gp 1
245-5829 Coolant/Battery Tester 1
Making contact with a running engine can cause burns from hot parts and can cause injury from rotating parts.When working on an engine that is running, avoid contact with hot parts and rotating parts.
The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.
Illustration 2 g00876179
4C-6500 Digital Thermometer
The 4C-6500 Digital Thermometer is used in the diagnosis of overheating conditions and in the diagnosis of overcooling conditions. This group can be used to check temperatures in several different parts of the cooling system. Refer to the tool's Operating Manual for the testing procedures.
Illustration 3 g01311364
285-0910 Multi-Tool Gp
The 285-0910 Multi-Tool Gp is used to check the air flow through the radiator core. Refer to the 285-0910 Multi-Tool Gp manual for instructions in order to check the air flow.
Illustration 4 g00286276
9U-7400 Multitach
The 9U-7400 Multitach Tool Group is used to check the fan speed for an engine. Refer to Operating Manual for the testing procedure.
Illustration 5 g00286369
9S-8140 Pressurizing Pump
The 9S-8140 Pressurizing Pump is used to pressure test the radiator's filler cap. This pressurizing pump is also used to pressure test the cooling system for leaks.Check the coolant frequently in cold weather for the proper glycol concentration. Use the 245-5829 Coolant/Battery Tester Gp in order to ensure adequate freeze protection. The tester gives immediate, accurate readings. The tester can be used for antifreeze or coolants that contain ethylene or propylene glycol.Making the Correct Coolant Mixtures
Adding pure antifreeze as a makeup solution for the cooling system top-off is an unacceptable practice. Adding pure antifreeze increases the concentration of coolant in the cooling system. This increases the concentration of the dissolved solids and the undissolved chemical inhibitors in the cooling system. Add the antifreeze and water mixture in the same concentration as your cooling system. The following chart assists in determining the correct concentration of antifreeze and water. Refer to Operation and Maintenance Manual, "Lubricant Viscosities and Refill Capacities".