Engine overhauls · On site
Generator Engine Overhauls and Major Mechanical Repairs
We carry out generator engine overhauls and major mechanical repairs on site, on residential, commercial and industrial generators. We confirm the wear before we quote, so you pay for an overhaul only when the engine needs one. An engine overhaul typically costs R9,000 to R28,000+ and a complete rebuild R18,000 to R55,000+, confirmed in a written quote.
Callout fee waived when you accept our written quote. 1-year workmanship guarantee. See prices
- Done at your premises
- Wear confirmed before we quote
- Written quote first
- 1-year workmanship guarantee
- Onsite across Gauteng
What an overhaul is
When a generator engine needs an overhaul
An overhaul restores an engine that has worn, rather than replacing one failed part. Depending on what we find, it is a top-end overhaul (the cylinder head, valves, gaskets and injectors) or a fuller rebuild that also covers the pistons, rings, cylinder liners where fitted, and the main and big-end bearings.
Diesel generator engines wear in recognisable ways: blue or white smoke that does not clear once the engine is warm, oil use that keeps rising, oil pushed out of the crankcase breather, harder starting as compression falls, low oil pressure on a warm engine, or a knock that changes with the load.
All generator repairs and engine overhauls are carried out on site at your premises. The set stays where it is, which matters for a standby generator that protects a home or a business, and you can see the work as it is done.
An overhaul is not always the right answer. When an engine has very high hours, a cracked block or head, or parts that are no longer made, we put the overhaul quote next to the cost of replacing the engine or the set, and you choose.
How it works
How an overhaul is quoted and carried out
The order matters: a fuel or injector fault can look like engine wear, and an overhaul does not fix a fuel problem.
01
Confirm the wear
We check how the engine starts, smokes, uses oil and holds oil pressure, look for blow-by at the breather, and look for fuel or coolant in the oil, before anything is stripped.
02
Scope and written quote
You get a written quote that says whether the work is a top-end overhaul or a full rebuild, which parts are replaced, and what it costs.
03
Parts matched to the engine
Parts are matched to the engine plate and serial number. Parts carry the supplier’s warranty where one applies.
04
Strip, measure and rebuild on site
The engine is stripped at your premises, worn parts are measured against the engine’s limits, and it is rebuilt with new gaskets and seals.
05
First start and testing
We start and run the engine, then check oil pressure, temperature, smoke, voltage and frequency. A load bank test can prove it under load if you need that.
06
Handover
We explain what was done and which parts were fitted, and when the first service after the overhaul is due.
Scope
What an overhaul can include
Only the parts the inspection shows are worn go into the quote.
Cylinder head and valves
Valve seats, guides and springs, and the head gasket. Head work is the core of a top-end overhaul.
Pistons, rings and liners
Worn rings and liners let oil into the cylinders and gases into the crankcase, which shows as blue smoke and blow-by.
Crankshaft bearings
Main and big-end bearings, checked when oil pressure is low on a warm engine or a knock appears under load.
Gaskets and seals
Every joint opened is resealed, so an overhaul also ends long-standing oil leaks.
Injectors and fuel delivery
Injectors are tested as part of the job, because a poor spray pattern damages new rings and liners quickly.
Cooling and lubrication parts
Water pump, thermostat, hoses and oil cooler where fitted, so a rebuilt engine is not let down by a worn ancillary.
Signs of engine wear and what they point to
Use this to describe what you are seeing when you call. Several of these also have causes that are not wear, which is why we test before we quote.
| What you notice | Likely cause | What we do |
|---|---|---|
| Blue smoke once the engine is warm | Oil burning in the cylinders: worn rings, liners or valve guides | Check oil use and blow-by; quote a top-end or full overhaul |
| White smoke that does not clear | Coolant reaching the cylinders (head gasket or cracked head), or fuel not burning | Check coolant loss and the oil, then the head and the injectors |
| Oil use rising, oil at the breather | Blow-by past worn rings or liners | Measure oil use and blow-by before recommending an overhaul |
| A knock that changes with load | Bearing wear, a piston problem or an injector fault | Stop running the set; inspect before more damage is done |
| Low oil pressure when warm | Worn bearings, a tired oil pump, or a faulty sender | Confirm the pressure with a gauge before the engine is condemned |
| Black smoke and low power | Usually air or fuel: filters, injectors or overload, not wear | Rule out fuel and air faults first; they cost far less than an overhaul |
Overhaul prices are on our generator repair cost guide, next to every other published range.
Common Questions
Questions about generator engine overhauls
How much does a generator engine overhaul cost?
An engine overhaul typically costs R9,000 to R28,000+ and a complete rebuild R18,000 to R55,000+. The engine size, the parts it needs and how far the wear has gone set the price, which is confirmed in a written quote before work starts.
Do you overhaul engines on site?
Yes. All generator repairs and engine overhauls are carried out on site at your premises. The generator does not have to be transported.
How do I know if my generator engine needs an overhaul?
Blue or white smoke that does not clear when warm, rising oil use, oil at the breather, harder starting, low oil pressure on a warm engine and a knock under load are the usual signs. Several have cheaper causes, so we test before we recommend an overhaul.
What is the difference between a top-end overhaul and a full rebuild?
A top-end overhaul covers the cylinder head, valves, gaskets and injectors. A full rebuild also covers the pistons, rings, liners where fitted and the crankshaft bearings. The inspection decides which one the engine needs.
Should I overhaul the engine or replace the generator?
It depends on the engine’s hours, its condition and whether parts are still available. We put the overhaul quote next to the cost of replacing the engine or the set so you can compare. Our repair-or-replace guide explains how to weigh it up.
Which generators do you overhaul?
We carry out generator engine overhauls and major mechanical repairs on site, on residential, commercial and industrial generators. Send a photo of the engine data plate so we can check parts before we visit.
How long does an overhaul take?
It depends on the engine and on how quickly parts arrive. We give you a timeline with the quote, and tell you straight away if a part has a long lead time.
Is an overhaul guaranteed?
Workmanship is guaranteed for 1 year. Parts carry the supplier’s warranty where one applies.
Can I keep running a generator that knocks or has low oil pressure?
No. Stop the set and call us. Running an engine with a knock or low oil pressure can turn a bearing repair into a full rebuild.
Still unsure what the fault is? Call or WhatsApp 082 057 4605 for onsite diagnosis.
Related Pages
Related repairs and guides
- Diesel Generator Repairs Fuel, starting and engine faults
- Injector Service Spray pattern and fuel delivery
- White Smoke Coolant, fuel or a cold engine
- Blue Smoke Oil burning in a worn engine
- Knocking Noise Bearings, pistons or injectors
- Low Oil Pressure Real pressure loss or a sender
- Repair or Replace Comparing an overhaul with a new set
- Load Bank Testing Proving the engine under load
- Industrial Servicing & Maintenance Servicing by running hours on large plant
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
Describe what the engine is doing
Send the make and model from the data plate, the running hours, and what you have noticed: smoke colour, oil use, knocking or hard starting.
- 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.