625 589 01 21 00
Measuring hose
Tester
Adapter
957 589 02 63 00
442 589 00 90 00
W20.40-1127-06
Check hydraulic motor and hydraulic pump
1 Detach electrical connector (1) at hydrostatic fan proportional valve (Y66)
2 Start engine.
Engine must be cold.
3 Point digital tachometer at fan (2), read fan speed off on digital tachometer and hydraulic pressure from pressure gauge (3).
Check at different engine speeds (according to table)
4 Compare fan speed and hydraulic pressure according to table.
If the hydraulic pressure is too low, replace hydraulic pump.
If the hydraulic pressure and fan speed is okay or the hydraulic pressure is okay and the fan speed too low, check hydraulic motor (4) and hydrostatic fan proportional valve (Y66)
5 Switch off engine.
Engine speed (rpm) | Fan speed (rpm)10% | Hydraulic pressure (bar)10 % |
600 | 790 | 30 |
800 | 980 | 40 |
1000 | 1360 | 72 |
1500 | 1960 | 142 |
2000 | 2330 | 196 |
W20.40-1127-06
Check function of hydraulic engine and hydrostatic fan proportional valve (Y66)
6 Attach electrical connector (1) to hydrostatic fan proportional valve (Y66).
7 Start engine.
Engine must be at operating temperature.
8 Point digital tachometer at fan (2), read fan speed off on digital tachometer and hydraulic pressure from pressure gauge (3).
Check at different engine speeds (according to table)
9 Compare fan speed and hydraulic pressure according to table.
The hydrostatic fan proportional valve (Y66) is actuated by the engine control unit (MR) by various currents.
If the hydraulic pressure is okay and the fan speed is too low, replace hydraulic motor (4) with hydrostatic fan proportional valve (Y66).
10 Switch off engine.
Engine speed (rpm) | Fan speed (rpm)10% | Actuation of proportioning valve (mA)10 % | Hydraulic pressure (bar)10 % |
600 | 550 | 945 | 20 |
800 | 520 | 972 | 19 |
1000 | 560 | 972 | 19 |
1500 | 590 | 972 | 20 |
2000 | 700 | 972 | 21 |