Service parts for the T120
Grouped by system, with how many of each the parts manual calls for.
Air intake
1 requiredFuel system
1 requiredOil system
1 requiredBelts
1 requiredCooling system
1 requiredPrices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.
Specifications
| Fuel | diesel |
|---|---|
| Frequency | 60.0 Hz |
| Standby power | 100 kW |
| Standby kVA | 125 |
| Prime power | 95 kW |
| Alternator | Stamford/AvK UCI274DIL32D |
| Voltage options | 208 V, 220 V, 240 V, 440 V, 480 V |
| Phase | 3 |
| Power factor | 0.8 |
| Circuit breaker | 350 A |
| Sound level | 68.0 dBA @ 7 m |
Engine
| Coolant capacity | 8.5 L |
|---|---|
| Displacement | 4.5 L |
| Aspiration | turbocharged and charge air cooled |
| Rated speed | 1800 rpm |
Maintenance & consumables
for the Cummins/Onan QSB5-G5NR3| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | Air Filter - Primary | 125561 | Amazon eBay | ||
| Fuel filter | Fuel Filter | 125551 | Amazon eBay | ||
| Oil filter | Oil Filter | 125550 | Amazon eBay | ||
| Belt | Belt | 125552 | Amazon eBay FridayParts $77.87 | ||
| Coolant filter | Coolant Filter | 8C-3600 | Amazon eBay |
Common questions
What size generator is the Terex T120?
The Terex T120 is rated 100 kW standby (125.0 kVA).
What engine does the Terex T120 use?
The Terex T120 is powered by the Cummins/Onan QSB5-G5NR3 engine.
Is the Terex T120 diesel or gas?
The Terex T120 runs on diesel.
Which alternator is fitted to the Terex T120?
The Terex T120 uses a Stamford/AvK UCI274DIL32D alternator.
Which oil filter part number does the Terex T120 take?
The Terex T120 uses oil filter part number 125550.
What fuel filter fits the Terex T120?
The Terex T120 uses fuel filter part number 125551.
What air filter does the Terex T120 use?
The Terex T120 uses air filter part number 125561.
Troubleshooting
6Symptoms & remedies
| Symptom | Cause | Remedy |
|---|---|---|
| No generator output voltage | Circuit breaker tripped | Reset circuit breaker |
| Low generator output voltage | Voltage adjustment set too low | Adjust voltage potentiometer |
| Low engine speed | Call TEREX Service | |
| Fluctuating or surging generator output voltage | Check engine fuel, oil, and air filters | |
| High generator output voltage | Voltage adjustment potentiometer set too high | Adjust potentiometer |
| High engine speed | Call TEREX Service |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing. Full Terex T120 troubleshooting guide (14 entries) →
Parts
15| Part # | Description | Qty | System | |
|---|---|---|---|---|
| 101-4000 | Gasket | 385 | Gasket | Amazon eBay |
| 125550 | Oil Filter | Oil filter | Amazon eBay | |
| 125551 | Fuel Filter | Fuel filter | Amazon eBay | |
| 125552 | Belt | Belt | Amazon eBay FridayParts $77.87 | |
| 125561 | Air Filter - Primary | Air filter | Amazon eBay | |
| 125562 | Air Filter - Secondary | Air filter | Amazon eBay | |
| 127-0826 | Battery | 685 | Battery | Amazon eBay |
| 153-5720 | Battery | 147 | Battery | Amazon eBay |
| 250-0486 | Oil Filter | 34 | Oil filter | Amazon eBay |
| 250-0488 | Spark Plug | 31 | Spark plug | Amazon eBay |
| 8C-3600 | Coolant Filter | 375 | Coolant filter | Amazon eBay |
| 8C-3601 | Air Filter | 250 | Air filter | Amazon eBay |
| 8C-3620 | Belt | 350 | Belt | Amazon eBay |
| 8C-3627 | Fuel Filter | 30 | Fuel filter | Amazon eBay |
| 134277 | T70, T90 & T120 Super Quiet Generator Maintenance Schedule | Service part / kit | Amazon eBay $34.00 |
Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.
Fuel consumption
| Rating | Load | L/h | gal/h |
|---|---|---|---|
| Prime | 4.4 | 16.6 | |
| Prime | 50% | 3.4 | 13.0 |
| Prime | 75% | 5.0 | 19.0 |
| Standby | 5.6 | 21.0 | |
| Standby | 100% | 6.0 | 23.0 |