Cooling System 6. Check thermostat, and pressure test radiator cap. 7. Make sure water pump and drive belt are operational. 8. Check and inspect wiring from sensor for shorting or damage. If none of those are found to be cause do following: 1. Drain coolant from system, so level is lower than installed position of temperature sensor. 2. Remove and replace temperature sensor. Use pipe sealant with Tefl on ® on threads. 2. Remove dipstick and check appearance of oil in crankcase. Another method would be to remove an oil drain plug and drain a small amount of oil for inspection. A milky or an opaque color, similar to chocolate milk, indicates presence of engine coolant in oil.
Check for a blown head gasket (step 3 below) or a possible crack or internal leakage from water jacket. 3. Remove spark plugs. Apply 14-15 lbs. of pressure and listen/inspect for internal coolant leakage into cylinder/combustion chambers. This can denote a head gasket failure/leak. If required, further test by performing a Cylinder Leakdown Test as described in Troubleshooting. Cooling System Leakage Test A pressure test of cooling system can be performed as a relatively simple means of determining whether cooling system may contain a leak. A pump/pressure type cooling system tester with appropriate 45 mm adapter may be used to check cooling system and radiator cap. Test Instructions 1.
With engine cool, carefully remove radiator cap (see Pressure Radiator Cap). Make sure all parts of cap and adapter are clean. Install cap on corresponding adapter and make sure it is completely seated. Install adapter onto tester and lock in place. 2. Pressurize tester to 15 psi. 3. Observe indicated pressure. It should hold steady and not decrease or leak down. If leakage is detected, cap should be replaced. If tester pressure is increased to 16 psi, or above, cap should then bleed off this excess pressure. 4. Install and lock system adapter and tester onto neck of cooling system. Pressurize tester to 14-15 psi. 5. Observe system pressure on gauge.
Gauge Needle Holds Steady If gauge needle holds steady, there should be no serious leaks in system. It is however, recommended that all connections be checked for overall condition anyway, using a fl ashlight. Gauge Needle Drops Slowly If gauge needle drops slowly it indicates presence of a small leak or seepage. Check all components and connections for signs of leakage. Check condition of radiator hoses. If they swell excessively while testing system, they may be weak and should be replaced. Gauge Needle Drops Quickly A steady drop or loss of pressure indicates serious leakage is occurring within system, which must be located and corrected before engine is returned to service.
If a pressure loss is noted: 1. With pressure on system, apply a soap/water solution and check all joint connections, hoses, and cooling system components for external leakage. Repair or replace as required. 41 66 690 01 Rev. C KohlerEngines.com