Kohler LH630-775 Service Manual page 88

4. After the engine has sufficiently cooled, check the
coolant level in the system to make sure it is not
low, or improperly mixed.
5. Check cooling system for leaks.
6. Check the thermostat, and pressure test the
radiator cap.
7. Make sure the water pump and the drive belt are
operational.
8. Check and inspect the wiring from the sensor for
shorting or damage.
If none of those are found to be the cause do the
following:
1. Drain coolant from the system, so the level is
lower than the installed position of the
temperature sensor.
2. Remove and replace the temperature sensor. Use
pipe sealant with Teflon
Cooling System Leakage Test
A pressure test of the cooling system can be
performed as a relatively simple means of
determining whether the cooling system may contain
a leak. A pump/pressure type cooling system tester
with the appropriate 45 mm adapter may be used to
check the cooling system and the radiator cap. A
typical tester and adapter is shown in Figure 7-14.
Figure 7-14. A Typical Tester and Adapter.
®
on the threads.
Test Instructions
1. With the engine cool, carefully remove the
radiator cap (see Pressure Radiator Cap Section).
Make sure all parts of the cap and adapter are
clean. Install the cap on the corresponding
adapter and make sure it is completely seated.
Install the adapter onto the tester and lock in
place. See Figure 7-15.
Figure 7-15. Adapter Installed onto the Tester.
2. Pressurize the tester to 15 psi.
3. Observe the indicated pressure. It should hold
steady and not decrease or leak down.
If leakage is detected, the cap should be replaced.
If the tester pressure is increased to 16 psi, or
above, the cap should then ''bleed off'' this excess
pressure.
4. Install and lock the system adapter and tester
onto the neck of the cooling system. Pressurize
the tester to 14-15 psi. See Figure 7-16.
Figure 7-16. Adapter and Tester Installed.
Section 7
Cooling System
7.7
7