Radiator & Cooling System Repairs
Overheating destroys engines faster than almost any other fault, and on standby sets it usually appears the first time the machine is asked to take real load. We inspect, pressure-test and repair generator and industrial-engine cooling systems rather than condemning a radiator on appearance.
What the work covers
- Pressure testing to locate leaks under working conditions
- Core cleaning, flushing and blockage assessment
- Tube, core and end-tank repair where the core is serviceable
- Radiator cap and thermostat testing
- Hose, clamp and fan-drive inspection
- Coolant condition and inhibitor assessment
- Cooling-system troubleshooting on running sets
Symptoms we see
- Coolant leakage
- High-temperature shutdown under load
- Blocked or fin-damaged core
- Corroded or split end tanks
- Contaminated coolant
- Weak airflow through the radiator
Understanding it
A generator radiator is a heat exchanger: hot coolant from the engine passes through a matrix of thin tubes bonded to fins, and the engine-driven fan pulls air across that matrix to carry the heat away. It has to reject the full waste heat of the engine — roughly as much energy as the set delivers as electricity — every second it runs on load. When it cannot, cylinder-head and liner temperatures rise and the damage that follows is measured in whole engines, not radiators.
Full technical guide — causes, repair, parts & prevention
Why it fails — common causes
- Airside blockage
- Dust, chaff, insects and oily film bridge the fins and choke airflow. This is the single most common cause on Kenyan sites — dusty yards, grass, and cooling air drawn through an unfiltered louvre. The core looks intact but cannot breathe.
- Internal scaling and silting
- Hard water, plain water without inhibitor, and mixed coolants leave scale inside the tubes. Scale is an insulator; a thin layer collapses heat transfer and blocks the smaller tubes entirely.
- Corrosion and electrolysis
- Missing supplemental coolant additive lets the tube-to-fin bond corrode. Stray current through the coolant (a bad earth) pits the tubes electrolytically, producing pinhole leaks.
- Mechanical and thermal fatigue
- Vibration cracks the header-tank seams and solder joints; repeated heat cycling splits end tanks. A missing or wrong-rated pressure cap raises system pressure and finds the weakest seam.
- Fan and shroud faults
- A slipping fan belt, a failed viscous drive or a missing shroud all reduce airflow and are frequently mistaken for a blocked core.
How we repair it
- 1.Pressure-test the cold system to locate leaks before stripping anything — a leak found under pressure is a leak, a wet patch is a guess.
- 2.Remove the radiator, drain and inspect the core, tanks and seams.
- 3.Rod-out and back-flush the tubes; chemically de-scale where internal fouling is found.
- 4.Repair serviceable cores — re-solder or seal leaking tubes, or block off a small number of dead tubes within the derating limit; recore where the matrix is beyond repair.
- 5.Repair or replace end tanks and header seams; renew the filler neck and test the pressure cap.
- 6.Renew hoses, clamps and the thermostat as required, and check the fan, belt and shroud before refit.
How we test it before handover
- Pressure test to the system rated pressure and hold — no drop permitted.
- Flow check to confirm the core is not internally restricted.
- Run the set up to operating temperature and verify it holds temperature on load, not just at idle.
- Confirm the thermostat opens at its rated temperature and the fan moves the expected air.
Parts & materials used
- Radiator cores / recore kits
- End tanks and header gaskets
- Pressure caps rated to the system
- Thermostats
- Hoses, clamps and fan belts
- Coolant and supplemental coolant additive (SCA)
How to prevent it happening again
- Clean the core on a schedule matched to the site — weekly in dusty or agricultural yards, not annually.
- Use the correct coolant with inhibitor, never plain water; top up with the same coolant, never mixed types.
- Fit and maintain intake louvres and keep the plant room free of grass and litter.
- Replace the pressure cap when it is due — it is the cheapest part on the engine and protects every seam.
- Fix a slipping belt or a bad earth immediately; both destroy radiators indirectly.
