Scheduled Maintenance (Türkiye)
Scheduled generator maintenance: step-by-step service, interval table by hours and months, mobile service for all brands in the İstanbul and Ankara regions.
Service request: Send your service request for your generator and our team will contact you. Service request form
A generator spends most of its life waiting, yet it must start the very moment it is needed. Regular maintenance is the most reliable way to make sure it starts without problems at that moment. During scheduled maintenance the engine, alternator, control panel, battery and fuel system are checked at set intervals, and worn parts are replaced before they cause a fault.
Mobile service vehicle for on-site work; maintenance and repair for all generator brands. Service is provided in the İstanbul and Ankara regions; for other locations, our team will contact you. In the İstanbul and Ankara regions we respond to breakdowns within 2–4 hours. You can report breakdowns 24/7 to our breakdown line by phone or WhatsApp.
What does maintenance cover?
- Engine: oil and oil filters, fuel and air filters, belts, coolant, leak checks
- Alternator: connections, insulation and output values
- Control panel: controller, alarms, terminals
- Battery and charging system: voltage, connections, battery charger
- Fuel system: tank, hoses, water separator
- Performance test: running the generator and measuring its values
The results are recorded on a scheduled inspection form; any work required is reported to you and carried out with your approval.
Maintenance steps
During a scheduled maintenance visit, our service team carries out the following steps in order:
- Initial check: The generator’s running hours, alarm history and last service record are read. A visual check is made for leaks, loose connections and damage.
- Oil and oil filter: Engine oil and the oil filter are replaced with the grade and quantity specified by the engine manufacturer.
- Fuel system: Fuel filters and the water separator are checked or replaced; water and sediment are drained from the bottom of the tank, and hoses and connections are checked.
- Air filter: The air filter restriction indicator is checked and the filter is replaced if necessary.
- Cooling system: Coolant level and antifreeze concentration are measured; the radiator core, hoses and clamps are checked. The block heater is tested.
- Belts: Tension and wear of the fan and charging alternator belts are checked.
- Battery and charging: Battery voltage is measured, terminals are cleaned and the battery charger is checked.
- Electrical connections: Connections of the alternator, panel and power cables, as well as earthing, are checked.
- Controller and ATS: Alarm and protection functions, automatic operation and, where fitted, the transfer switch (ATS) changeover are tested.
- Run and load test: The generator is started; voltage, frequency, oil pressure and engine temperature are measured. Where required, a load test is carried out with a load bank.
- Report: The work done, the parts replaced and the recommended work are recorded on the service form.
For a detailed list, see our generator maintenance checklist.
Maintenance interval table
The table below shows intervals commonly used for diesel generators. The values are for general information; the values in the engine manufacturer’s operation and maintenance manual always take precedence. Maintenance is carried out at the running hours or the calendar interval, whichever comes first.
| Task | By running hours | By calendar |
|---|---|---|
| Visual check, oil and coolant levels, battery voltage | – | Weekly |
| Short no-load run and alarm check | – | Weekly or monthly |
| Engine oil and oil filter change | 250–500 h | 12 months |
| Fuel filter and water separator | 250–500 h | 12 months |
| Air filter check / change | 250–500 h (per indicator) | 12 months |
| Belt check | 250 h | 6–12 months |
| Battery replacement | – | Based on test results |
| Coolant change | 2,000–3,000 h | 24 months |
| Load test | – | 12 months |
In severe conditions such as dust, high temperatures or poor-quality fuel, the intervals are shortened. During the warranty period, carrying out and recording maintenance at the intervals in the manual is required to keep the warranty valid.
Why scheduled maintenance?
- It prevents sudden breakdowns and costly repairs.
- It preserves fuel efficiency and generator service life.
- It is required to keep the warranty valid.
- It ensures that the generator starts automatically when the power fails.
Service for all generator brands
Our scheduled maintenance service is not limited to Terex Diesel sets. We maintain and repair generators of all brands built with Perkins, Cummins, Baudouin, Volvo Penta, FPT Iveco and other engines. Our mobile service vehicle arrives on site with filters, oil and commonly used spare parts, so in most cases maintenance is completed in a single visit.
Maintenance contract and records
For businesses that want regular maintenance on a fixed schedule, we offer a generator maintenance contract. The contract sets out the visit frequency, the work covered and the reporting in advance. You can download the monthly maintenance and scheduled inspection forms from our Documents page. For parts that need replacing during maintenance, see our spare parts supply page.
Service request
For scheduled maintenance, fill in the service request form; simply give the generator’s make, model, power, running hours and location. Our team will contact you to schedule the maintenance date. For emergencies, see our 24/7 breakdown support page.
Frequently asked questions
How often should a generator be serviced?
The maintenance interval depends on the engine manufacturer's instructions, running hours and operating conditions. Even for generators on standby duty, weekly routine checks and a comprehensive service at least once a year are recommended; our service team draws up the exact plan for your generator.
Does a standby generator that rarely runs still need maintenance?
Yes. In a generator that runs little, oil, fuel and coolant lose their properties over time, the battery weakens and water can collect in the tank. For this reason maintenance is based on the calendar as well as on running hours, whichever comes first.
How long does scheduled maintenance take?
It depends on the generator's power, the work to be done and the conditions on site. A routine service is usually completed on the same day; where parts must be replaced or a load test is needed, the duration is given to you in the service plan.
Do you service generators of other brands?
Yes. As well as sets built by Terex Diesel, we provide maintenance and repair for all generator brands. In your service request, simply give the generator's make, model, power and running hours.
In which regions do you provide scheduled maintenance?
Service is provided in the İstanbul and Ankara regions; for other locations, our team will contact you.
Is a maintenance contract required?
No. You can also request a one-off service. Under a maintenance contract the visit schedule is planned in advance and maintenance records are kept regularly. Details are on our generator maintenance contract page.