Generators make noise that’s a fact. But not all noise is normal. Some sounds are expected during operation. Others are signs of deeper technical problems that can lead to breakdowns or damage. If you’ve been asking, “what causes generator to make noise?” or noticing a generator making weird noise, this guide is for you.
As specialists in commercial and industrial power systems, we’ve seen the full range from perfectly normal hums to warning sounds that signal serious issues. We break down the types of noise, what’s acceptable, what’s not and why professional intervention is critical.
All generators produce some level of mechanical and combustion noise. The level depends on:
Generator type (diesel, petrol, gas)
Enclosure and insulation
Load conditions
Manufacturer design
A well-maintained diesel generator, for example, will emit a consistent low-frequency hum during operation. You may also hear slight variations when the load changes this is expected.
Typical sounds include:
Low engine hum
Soft cooling fan noise
Controlled exhaust discharge
These are normal operational sounds, particularly in commercial or industrial generators. If your generator has always sounded this way and is properly maintained, there’s likely no cause for concern.
The real concern starts when noise changes or increases unexpectedly. This is when clients start noticing their generator making weird noise and that’s a red flag.
If bolts, panels, or engine mountings become loose, they can create:
Rattling or banging sounds
Vibrations that get worse with load
Why it matters: Vibrations can escalate, damaging wiring, fuel lines, and sensors
Note: Don’t attempt to tighten parts yourself. Incorrect torque settings or missed safety checks can make things worse or unsafe.
High-pitched whining or grinding? That could mean internal parts such as:
Alternator bearings
Cooling fan bearings
Water pump components
are worn or failing.
Why it matters: Ignoring this can lead to seizure, overheating, or mechanical failure.
Note: Do not lubricate or disassemble parts without proper training. Accessing internal systems on a running or recently operated generator is dangerous.
Knocking or pinging noises might signal:
Poor fuel atomisation
Clogged injectors
Water contamination in diesel
Why it matters: Poor combustion can damage the engine over time and increase emissions.
Note: Diesel fuel system repairs involve high-pressure components. Leave it to certified technicians with the right diagnostic equipment.
If your generator sounds like it’s straining or you hear coughing or puffing noises, it could be:
A partially blocked muffler
Carbon build-up in the exhaust
Intake filter blockage
Why it matters: Backpressure can cause the engine to stall or overheat.
Note: Do not dismantle the exhaust system yourself. It can release hazardous gases or result in burns or other injuries.
Unusual noises at startup or shutdown are often related to:
Timing issues
Faulty sensors
Control panel faults
Electrical grounding or arcing
Why it matters: These problems may not stop the generator immediately but can severely shorten its lifespan or cause intermittent failures.
Note: These are electrical faults that require diagnostic tools and safety protocols. Do not attempt electrical tests or software resets yourself.
If your generator suddenly gets louder, sounds unusual, or behaves differently under load something is wrong.
It might be a simple maintenance issue or a sign of a critical system failure. Either way, continued use without diagnosis increases the risk of breakdown and puts your facility at risk of power loss.
Noise is often the first indicator of a failing system. It’s not just an annoyance it’s a warning signal. The sooner it’s inspected, the lower the risk of downtime, costly repairs, or equipment failure.
At Generator Control & Maintenance LTD, we handle generator diagnostics, repairs, and full-service maintenance for industrial and commercial clients across the UK. We don’t guess we investigate using:
Full acoustic and vibration analysis
Thermal imaging and sensor testing
Fuel, exhaust, and load system inspection
Our team identifies the source of the problem and provides long-term solutions, not temporary patches.
If your generator is making weird noise don’t ignore it and don’t open it yourself.
Call GCM. Let our engineers handle the technical side, safely and properly.
Your generator’s noise could be the first sign of a major fault. At GCM, we offer fast-response generator inspection and diagnostics across the UK. Don’t wait for a breakdown.
Call us today and let’s get your system running quietly and safely again.
WE’RE ALL ENGINEERS HERE…
We only work with a group of tried and trusted suppliers and use the most reliable and effective equipment – which doesn’t always mean the most expensive. And, as controls and systems are continually changing, we keep abreast of all the latest developments to provide you with robust long-term solutions.
