HomeTerexTerex T120C

Terex T120C Generator Set

The Terex T120C is a 96 kW (120 kVA) prime generator set powered by a Cummins/Onan QSB5-G3 NR3 engine. It is available at 208 V, 220 V, 240 V, 440 V and 480 V, single-phase and rated 350 A. It holds about 12.1 L (3.2 gal) of oil. The set measures 2790×1190×1620 mm (109.8×46.9×63.8 in) and weighs about 2445 kg (5390 lb). The same QSB5-G3 NR3 engine also powers generator sets from Cummins/Onan and Magnum.

4.5 L
Displacement
12.1 L
Oil capacity
1
Document types

Service parts for the T120C

Grouped by system, with how many of each the parts manual calls for.

Air intake

1 required

Fuel system

1 required

Oil system

1 required

Prices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.

Specifications

Prime power96 kW
Oil capacity12.1 L
Voltage options208 V, 220 V, 240 V, 440 V, 480 V
Phase3 phase,1 phase
Rated current350 A
Circuit breaker350 A
Dimensions (L×W×H)2790×1190×1620 mm
Dry weight2445 kg

Engine

Cummins/Onan QSB5-G3 NR3
Oil capacity12.1 L
Displacement4.5 L
AspirationTurbocharged and air-to-air aftercooled
Rated speed1800 rpm

Maintenance & consumables

for the Cummins/Onan QSB5-G3 NR3
ItemSpecCapacityPart #Interval
Air filterAir Filter - Primary125561 Amazon eBay
Fuel filterFuel Filter125551 Amazon eBay
Oil filterOil Filter125550 Amazon eBay
Battery
Belt
Coolant
Oil
Spark plug

Common questions

Which engine powers the Terex T120C?

The Terex T120C is powered by the Cummins/Onan QSB5-G3 NR3 engine.

What's the oil capacity on a Terex T120C?

The Cummins/Onan QSB5-G3 NR3 engine in the Terex T120C has an oil capacity of 12.1 liters.

What oil filter fits the Terex T120C?

The Terex T120C uses oil filter part number 125550.

What fuel filter fits the Terex T120C?

The Terex T120C uses fuel filter part number 125551.

Which air filter part number does the Terex T120C take?

The Terex T120C uses air filter part number 125561.

Troubleshooting

6

Symptoms & remedies

SymptomCauseRemedy
No generator output voltageCircuit breaker trippedReset circuit breaker
Low generator output voltageVoltage adjustment set too lowAdjust voltage potentiometer
Low engine speedCall TEREX Service
Fluctuating or surging generator output voltageCheck engine fuel, oil, and air filters
High generator output voltageVoltage adjustment potentiometer set too highAdjust potentiometer
High engine speedCall 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 T120C troubleshooting guide (14 entries) →

Parts

12
Part #DescriptionQtySystem
100-001Air Filter1Air filter Amazon Amazon eBay
100-002Fuel Filter1Fuel filter Amazon eBay
100-003Air Filter1Air filter Amazon eBay
100-004Coolant Filter1Air filter Amazon Amazon eBay
100-005Belt1Belt Amazon Amazon eBay $8.98 eBay KuduParts $239.99
100-006Spark Plug1Spark plug Amazon eBay
100-007Bolt (M10-1.5)1Bolt m10 1 5 Amazon eBay KuduParts $153.00
100-008Bolt (M12-1.75)1Bolt m12 1 75 Amazon eBay
125550Oil FilterOil filter Amazon eBay
125551Fuel FilterFuel filter Amazon eBay
125561Air Filter - PrimaryAir filter Amazon eBay
362PSL1606Generator ModelGenerator Amazon eBay

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

RatingLoadL/hgal/h
Prime4.416.6
Prime50%3.413.0
Prime75%5.019.0
Standby5.621.0
Standby100%6.023.0

Available documents

Service manual — 134277 (Terex)