Cooling systems
Generator Radiator & Cooling System Repairs
We repair generator radiators and cooling systems that let the engine run hot or shut down on temperature. The radiator, coolant, thermostat, water pump, hoses, belts and fan all work together to move heat out of a running engine. We find the part that is failing, including faults that only show under load, and we never open a hot cooling system.
Callout fee waived when you accept our written quote. 1-year workmanship guarantee. See prices
- Overheating diagnosed, not just reset
- Load and airflow included
- Cooling system opened only when cool
- Onsite across Gauteng
Heat has to leave the engine
Why does a generator cooling system matter?
A diesel or petrol generator turns a large share of its fuel into heat as well as electricity. If the radiator, the pump or the airflow cannot carry that heat away, the engine shuts down or keeps getting hotter. That shutdown is the protection doing its job, not a nuisance to clear.
The cause can be a blocked core, low coolant, a thermostat stuck shut, a water pump that is not circulating, a slack belt, a failed fan, scale in the coolant, a leak, or a canopy with no airflow. Too much load makes every one of those show up sooner.
If the system is full and still runs hot, we look at circulation and airflow. If it keeps losing coolant, we treat it as a leak until we find the cause. As a guide, cooling system repairs cost R1,800 to R5,000, and you get a written quote before any work.
Radiator, pump, belts and load
Generator radiator problems
Blocked or dirty radiators
Dust, debris and scale stop heat leaving the core. We inspect the outside of the core and the airflow path before we recommend a flush.
Thermostat faults
A thermostat stuck shut keeps coolant out of the radiator, and one stuck open can stop the engine reaching working temperature. We test it rather than replacing it on a temperature reading alone.
Water pump problems
If the pump is not moving coolant, the engine runs hot while the radiator stays cooler than it should. We confirm the pump has failed before we condemn the radiator.
Cooling hoses and belts
A collapsed hose, a glazed belt or a fan that is not turning stops circulation or airflow. We check these by eye first, without opening a hot system.
Generator overheating under load
An engine that is calm at idle and hot once the building connects may be short of cooling capacity, short of airflow, or overloaded. Our overheating guide covers that symptom.
Cooling-system testing
We check the level, leaks, belt and fan condition, temperature rise and behaviour under load. We pressure-test only once the engine is cool enough to open safely.
Common Questions
Questions about generator cooling systems
Why does a generator cooling system matter?
It carries away the heat your engine makes while producing power. If it cannot, the set overheats or shuts down.
The generator only gets hot under load. Is that the radiator?
It might be. Poor airflow, weak coolant circulation, a slipping belt and an overload can do the same, so we test the set under load to see which.
Can a dirty radiator cause overheating?
Yes. A blocked core or debris on the fins stops heat leaving. We inspect it before we replace any parts.
Should I open the radiator when it is hot?
No. A hot cooling system is under pressure and can spray scalding coolant. Leave the cap closed, and we will open it only once the engine has cooled.
Is low coolant a radiator fault?
Not necessarily. Low coolant means it is going somewhere, so we treat it as a leak until we find the cause. Our coolant leak repairs cover that diagnosis.
Do you replace thermostats and water pumps?
Yes, when our tests show that part is at fault. A high temperature reading alone is not enough to condemn either.
What should I send about the cooling fault?
Tell us whether it overheats at idle or under load, whether the coolant level in the overflow bottle is falling, and any high-temperature alarm text. If it has shut down hot, we are open 24/7 and arrive within 1 hour.
Still unsure what the fault is? Call or WhatsApp 082 057 4605 for onsite diagnosis.
Service Areas
Onsite visits across Gauteng
We come to your generator anywhere in Gauteng, 24/7. Choose your region for local suburbs, call-out details and the faults we see most there.
What to send before we attend
These details help us plan the visit and bring the right parts. Send what you can on WhatsApp; if you can’t find the model number, we still book the visit.
- 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 Visit
Tell us when the temperature rises
At idle, after a long run, or only under load? Mention it if coolant is disappearing too.
- Call
- 082 057 4605
- Message us on WhatsApp
What happens next
- We reply with questions about the generator, or to book a visit.
- A technician comes to you. For a breakdown we arrive within 1 hour.
- The fault is diagnosed on site and you get a written quote. No work starts until you accept it.
Charlie, lead technician: Degree in Mechanical Engineering, Degree in Electrical Engineering, Diesel Plant Fitter. Generator specialists since 2000.