Small diesel generators
Homes, workshops, small offices and mobile or site sets. The visit is still a diesel diagnosis: battery, fuel and shutdowns.
Diesel generator specialists
Diesel Generator Repairs Across Gauteng
Diesel backup is built for load, then asked to sit for weeks. We diagnose starting, fuel, cooling and automatic-start faults on commercial and residential diesel generators across Gauteng.
- Standby and commercial diesels
- Fuel, starting and cooling
- Onsite Gauteng repairs
- Listed diesel brands
Diesel Generator Brands We Repair & Service
Each card links to a dedicated diesel page. Honda diesel is not listed. Current Honda generator sets on this site are petrol.
Cummins
Standby and commercial diesel sets: starting, fuel delivery, cooling and output.
Perkins
Perkins-powered sets: filters, lift pumps, injectors and no-start diagnosis.
Caterpillar
CAT and Caterpillar standby sets: starting, fuel, cooling and planned maintenance.
Deutz
Deutz diesel engines in generator sets: hard starting, fuel delivery and cooling.
Volvo Penta
Volvo Penta standby engines: fuel, cooling, controllers and electrical output.
John Deere
John Deere diesel engines in commercial generator sets.
FG Wilson
FG Wilson and Wilson standby sets: engine, controller, battery and ATS.
Olympian
Olympian standby and commercial canopy sets.
Kohler
Kohler diesel standby only. Gas Kohler sets use a different page.
SDMO
SDMO and Kohler-SDMO standby systems: controllers, ATS and fuel.
Generac
Generac diesel standby sets, kept separate from Generac gas.
FAW
FAW and FAWDE diesel generator sets for commercial standby.
Scania
Larger Scania diesel standby and industrial generator sets.
Baudouin
Baudouin engines in commercial and industrial generator sets.
Doosan
Doosan diesel standby generators: starting, fuel, cooling and output.
Mitsubishi
Mitsubishi diesel generator engines: no-start, fuel, batteries and cooling.
MTU
Larger MTU diesel generator sets for industrial and critical standby.
Yanmar
Smaller and medium Yanmar diesel generator applications.
Kubota
Compact and medium Kubota diesel generator sets.
Iveco FPT
Iveco and FPT diesel engines in commercial generator systems.
Lovol
Lovol diesel standby and commercial generator sets.
Kirloskar
Kirloskar diesel generator servicing for no-start and output faults.
SDEC
SDEC diesel engines in commercial generator sets.
Kipor
Kipor diesel models only. Petrol Kipor sets use the petrol page.
Himoinsa
Himoinsa enclosed commercial sets and automatic standby systems.
Atlas Copco
Atlas Copco site, mobile and commercial diesel generators.
Aksa
Aksa diesel standby gensets for commercial sites.
Ricardo
Ricardo diesel engines used in generator sets.
Yangdong
Yangdong diesel engines in smaller and medium generator sets.
Denyo
Denyo enclosed and site diesel generator sets.
Hyundai
Hyundai diesel standby sets, separate from Hyundai petrol generators.
Mac Afric
Mac Afric diesel generator sets for workshops and small commercial sites.
Gentech
Gentech diesel generator sets sold for standby and commercial use.
Turner Morris
Turner Morris diesel sets for site and commercial use.
Diesel Generator Sizes We Service
Repair and service change with the size, the application, the engine, the alternator, the controller, the hours, the load, standby or prime duty, and the service history. A company-wide maximum kVA is not published. Share the figure on the plate.
Medium diesel generators
Offices, restaurants, retail, estates, schools and guest properties. These sets often sit behind an automatic start.
Large commercial diesel generators
Office buildings, warehouses, shopping facilities and larger residential developments. Cooling and transfer show up when the building actually switches.
Industrial diesel generators
Factories, production sites and major backup installations. Access, fuel condition and the controller alarm decide the first hour on site.
Silent and open-skid sets
Canopy sets need airflow and door access checked. Open-skid sets are easier to inspect and still need the same fuel, oil and electrical tests.
Single-phase and three-phase
Phase is read from the plate. Output tests follow that. Electrical repairs stay within what the visit can safely complete.
Why will a diesel generator not start?
A diesel generator may fail to start because of a flat battery, a weak battery, loose or corroded terminals, the starter, a controller fault, an emergency stop, a low-fluid shutdown, or a fuel fault.
Why does it crank but not start?
A diesel that cranks and does not fire is often fuel starvation, a blocked filter, contaminated diesel, air in the system, a lift pump, injection equipment, a fuel solenoid, or a control shutdown. The set is not stripped as a first step.
AVR, frequency, controllers and ATS
Missing or unstable voltage is an AVR, excitation, alternator, breaker or wiring fault once the engine is running. Low or high frequency follows engine speed, governor, load and controller sensing. Settings are not published for adjustment at home. Deep Sea and SmartGen alarms are recorded as displayed. An ATS fault is a start signal or a transfer that never happens. Nobody is asked to work inside live switchgear.
Alternator winding and insulation faults are assessed with generator rewinding. Leroy-Somer work sits on its own alternator page: Leroy-Somer alternator repairs.
Overheating, oil pressure and load testing
High temperature can be low coolant, a leak, a blocked radiator, a hose, a belt, a thermostat, a water pump, too much load, or poor canopy airflow. A low-oil-pressure shutdown is not cleared by repeated resets when the pressure fault may be real. Load bank testing, where the site and the set allow it, shows cooling and output under load. A five-minute idle does not.
What to send before the callout
Brand, engine brand if it differs, model, kVA, a photo of the data plate and the controller, any alarm text, what happens when start is pressed, whether it cranks, whether it fires, whether voltage appears, whether the ATS transfers, and the suburb. Unknown fields can be left blank.
Diesel generator repairs across Gauteng
The Service
Diesel standby fails differently from a petrol portable
Most backup power in Gauteng commercial buildings, warehouses and larger estates is diesel. The engines are built for loaded hours, but standby duty is a different life: long sits, short test runs, and then a sudden full load when the grid drops. That pattern produces diesel-specific faults that a petrol portable never sees.
Fuel is the usual weak point. Diesel in a tank that is not turned over grows water and microbial growth. Filters clog, lift pumps lose prime, and injectors wear. The set may start on a monthly test and then fail on the first real outage because the fuel system was never asked to deliver at load.
Starting and cooling follow. Glow plugs and intake heaters matter on cold mornings in Pretoria and the Highveld. Larger radiators, oil coolers and canopies packed with dust show up as high-temperature shutdowns only when the ATS transfers a real commercial load. We diagnose those as diesel cooling jobs, not generic “engine faults”.
We repair diesel generators on site across Johannesburg, the East Rand, Sandton and the rest of Gauteng — from smaller residential standby diesels to commercial and industrial sets. Brands we commonly see include Cummins, Perkins, Caterpillar, Deutz, Volvo, FG Wilson and Kohler.
Diesel set down?
Call or WhatsApp 082 057 4605 for onsite diesel generator diagnosis in Gauteng.
Diesel-Specific
Faults we see on diesel generators
Hard starting when cold
Glow plugs, heater relays, compression and battery condition on diesel standby that sits between outages.
Fuel contamination
Water, sludge and blocked filters after diesel has sat in the tank. Often discovered only when load is applied.
Injector, lift-pump and injection-pump faults
Smoke, rough running, fuel knock or a set that cranks strongly but will not fire. The lift pump, injection pump and injectors are tested as a system, not swapped one at a time.
Wet stacking on light load
Unburnt fuel in the exhaust from generators that never see enough load on test. Load-bank testing is the check, not a longer idle.
Overheating under transfer
Radiators, coolant and canopy airflow on sets that only run hot when the building actually switches over.
Control and ATS issues
Diesel standby lives and dies on automatic start. Controller inhibits and transfer faults are diagnosed with the engine, not instead of it.
How We Work
Duty, fuel and load — then the repair
- 01
Identify duty and fuel
Standby versus prime, tank condition and whether the fault appears at idle or only on load.
- 02
Diesel-specific checks
Glow circuit, fuel pressure, filters, injectors as required, coolant and air path through the canopy.
- 03
Quote the actual repair
You get the scope in writing. We do not treat a contaminated tank as an injector-only job.
- 04
Repair and loaded run
After the work we confirm starting and behaviour under a representative load where the site allows.
Fuel Type
Choose the page that matches the engine
Petrol repairs on this site are a separate page because the fuel system, ignition and typical unit size are different. If you have a small home petrol set, that content will match better. If you have a canopy diesel with an ATS, stay here.
Diesel work more often includes fuel polishing or tank hygiene, glow-plug circuits, and proving the set on load. Petrol work more often includes carburettors, spark and stale fuel in small tanks.
Typical diesel jobs
Standby canopies, commercial backup, fuel and cooling
Typical petrol jobs
Home portables, carburettors, spark and small tanks
Shared faults
Batteries, control panels and “no output” AVRs
Related pages
Fuel system repairs and load-bank testing
Google reviews of ProService Generator Repairs
Google Review
When our 3-phase diesel plant started smoking, their heavy-plant mechanics traced the issue to a microscopic crack in an injector line and fitted specialized parts within hours.
Google Review
True experts in heavy-duty diesel engines.
Common Questions
Diesel generator repairs — questions
What diesel generator brands do you repair?
Supported diesel brands include Cummins, Perkins, Caterpillar, Deutz, Volvo Penta, John Deere, FG Wilson, Olympian, Kohler, SDMO, Generac, FAW and others listed on this page. Each published brand has its own page.
What sizes of diesel generators do you service?
Work covers smaller standby sets through larger commercial and industrial machines. A maximum kVA is not published. The data plate on the set decides the visit.
Do you repair commercial diesel generators?
Yes. Offices, retail, warehouses, estates and other commercial standby sets are diagnosed on site across Gauteng.
Do you repair industrial generators?
Yes, where the installed diesel set can be taken on. Factory and plant-room machines are quoted from the plate, the access and the fault.
Why will my diesel generator not start?
A diesel generator may fail to start because of the battery, the starter, the fuel system, a controller shutdown or an engine protection fault.
Why does my diesel generator crank but not start?
A diesel that cranks and will not fire is often a fuel-delivery, air-in-fuel, shutdown or engine-related problem. Filters and air are checked before injection equipment is condemned.
Can you diagnose injector and injection-pump problems?
Yes. Hard starting, smoke, uneven running and poor load response are investigated. Those symptoms are not treated as proof that an injector has failed.
Do you repair generators producing no voltage?
Yes. Once the diesel is running, missing voltage is checked at the breaker, the AVR and the alternator.
Do you diagnose ATS and controller problems?
Yes. Deep Sea, SmartGen and other panels are read as displayed. Transfer faults are diagnosed without asking anyone to work inside live switchgear.
Do you provide preventative diesel generator maintenance?
Yes. Standby sets that do not run every day still need oil, filters, coolant, batteries and a check of start and transfer. Intervals follow the machine and its hours.
Do you repair diesel generators on site?
Yes. Most diesel diagnosis and repair is done at your premises in Gauteng. Workshop work is reserved for jobs such as rewinding that cannot be finished in the canopy.
Why did my diesel start on test but fail in an outage?
Short unloaded tests do not stress fuel filters, injectors or cooling. A real transfer runs the engine harder and longer. Contaminated diesel and blocked radiators often appear only then.
Is black smoke always injectors?
No. Black smoke can be injectors, a dirty air filter, overload or a fuelling fault. We check air and load before assuming the injection pump is finished.
What is the difference between diesel and petrol generator repairs?
Diesel sets use compression ignition, injection equipment and usually larger cooling packs. Petrol sets use spark ignition and carburettors or simple injection on smaller frames. Diagnosis starts in different places even when both “will not start”.
Still unsure what the fault is? Call or WhatsApp 082 057 4605 for onsite diagnosis.
Related Services
Diesel faults and follow-on work
- Generator RepairsOnsite diagnosis of the fault
- Fuel System RepairsDiesel contamination and injectors
- Generator Not StartingStart-circuit diagnosis
- Cranks But Won't StartTurns over, will not fire
- Generator OverheatingCooling and airflow faults
- Load Bank TestingProve diesel output and temperature
- Generator ServicingScheduled diesel service visits
- Petrol Generator RepairsHome and portable petrol units
- Generator FAQsStarting, fuel, voltage and callout questions
- Generator SizeskVA bands for diesel sets
- Makes & ModelsDiesel brands with their own pages
- Industrial Generator RepairsLarger diesel plant and heavy standby
- Diesel Injector ServiceHard starting, smoke and rough running
- Fuel Pump RepairsDiesel delivery faults
- Black SmokeSoot under load or at startup
- White SmokeUnburnt fuel or a cold burn
- Commercial Generator RepairsOffices, retail and standby plant
- Generator Fault FindingDiagnosis before parts
- Generator MaintenancePlanned diesel readiness
- Alternator RepairsOutput once the diesel is running
- Controller RepairsAlarms and failed auto-start
- Cooling System RepairsRadiator, hoses and airflow
Service Areas
Diesel repairs across Gauteng
We repair diesel generators in Johannesburg, Sandton, Pretoria, Midrand, Centurion and across the East Rand, with callouts to the wider province.
- JohannesburgDiesel generator callouts
- PretoriaDiesel generator callouts
- SandtonDiesel generator callouts
- CenturionDiesel generator callouts
- MidrandDiesel generator callouts
- East Rand / EkurhuleniDiesel generator callouts
- RandburgDiesel generator callouts
- West RandDiesel generator callouts
- Vaal / Southern GautengDiesel generator callouts
What to send before we attend
ProService Generator Repairs confirms an onsite visit from these details. Send what you have. A missing model number does not stop the booking.
- Location
- The suburb or site, so the visit can be booked in the right area.
- Make and model
- The generator brand and model, if they are known.
- kVA
- The size printed on the data plate.
- Fuel type
- Diesel, petrol, LPG, natural gas, or dual-fuel.
- Controller model
- The module name on the panel, when it is visible.
- Fault or alarm
- What the set does, and any text on the screen.
- Photos
- The generator, the data plate, and the controller or alarm. Send these on WhatsApp.
Book a Repair
Need a diesel generator repaired?
Tell us the kVA if you know it, the brand, and whether it is a canopy standby set or an open industrial unit.
- Call
- 082 057 4605
- Message us on WhatsApp