Toro Workman 3000 Series Service Manual page 69

Engine Oil Pressure Switch
The switch is normally closed (NC) and opens with pres ­
sure. The switch opens at approximately 8 psi (55 kPa).
(See Oil Screen, Dipstick and Oil Filter Removal and
Installation for location).
1. Turn ignition key switch ON. Oil pressure lamp should
be on.
If oil pressure light is OFF:
1. Disconnect wire from switch and touch wire to a good
ground.
2. If lamp comes on, replace switch.
3. If lamp does not come on, check lamp and/or wiring
between lamp and switch for continuity.
Thermostat Test
If the engine overheats and a faulty thermostat is sus­
pected, the thermostat should be tested.
1. Remove the thermostat (see Water Pump, Hose, Pipe
and Thermostat Removal and Installation).
2. Put the thermostat in a container of water with a ther-
mometer and heat the water.
Valve cracking temperature
Full open temperature
3. If the thermostat fails to open, only partially opens, or
sticks, it should be replaced.
Workman 3000/4000 Series
80�C (180�F)
95�C (205�F) or more
valve lift of 8 mm (.31 in.)
Page 3 – 31
If oil pressure light is ON with engine running:
1. Shut off engine immediately.
2. Check switch by disconnecting wire. Light should go
out.
3. If light is still on, check for short circuit in wiring.
4. Install test gauge in engine oil pressure switch port.
Start engine and check for 30 psi (207 kPa) minimum at
1500 rpm. If engine pressure is good, replace switch. If
engine pressure is low, DO NOT operate the engine.
Figure 43
Liquid Cooled Gas Engine