How to Avoid Fuel Contamination (and What to Do If You Think Your Fuel Is Contaminated)
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Australia is currently facing a fuel supply crisis driven by global events, including disruptions to oil shipments and increased demand. This has led to:
- Temporary fuel shortages across multiple states
- Changes in fuel quality standards (including “dirty fuel”)
- Increased reliance on imported and alternative fuel sources
In fact, the government has temporarily allowed higher sulphur fuel into the market to maintain supply, which can affect fuel quality perception among drivers .
What Is Fuel Contamination?
Fuel contamination happens when unwanted substances mix with petrol or diesel, reducing its performance and damaging your engine.
Common contaminants:
- Water (most common cause)
- Dirt, rust, or debris
- Microbial growth (diesel bug)
- Incorrect fuel (petrol in diesel or vice versa)
- Excess sulphur or poor-quality fuel
In diesel, contamination is often caused by water ingress, which allows bacteria and fungi to grow inside the tank—commonly known as the “diesel bug” .
Petrol vs Diesel Contamination
Petrol Contamination
- More sensitive to chemical impurities
- Can damage fuel injectors and sensors
- Higher sulphur fuel (currently allowed temporarily in Australia) can affect emissions systems
Diesel Contamination
- More prone to water contamination
- Can develop bacteria and sludge
- Leads to clogged fuel filters and injector failure
Diesel contamination tends to be progressive and hidden, while petrol contamination is often immediate and noticeable.
Signs Your Fuel May Be Contaminated
Watch out for these early warning signs:
- Engine misfiring or rough idling
- Loss of power (especially under acceleration)
- Difficulty starting
- Excessive smoke (diesel vehicles)
- Fuel warning lights or check engine light
- Sudden drop in fuel efficiency
If multiple symptoms appear after refuelling, contamination is highly likely.
How to Avoid Fuel Contamination
1. Choose Reputable Fuel Stations
Stick to high-turnover stations where fuel is regularly replenished.
2. Avoid Refuelling During Deliveries
Fuel tanks can stir up sediment and debris when being refilled.
3. Keep Your Tank Above 1/4 Full
Low fuel levels increase condensation, especially in diesel vehicles.
4. Use the Correct Fuel Type
Misfuelling (petrol vs diesel) is still one of the most common and costly mistakes.
5. Service Your Vehicle Regularly
At HTR workshops, we often see contamination caught early during:
- Fuel system inspections
- Filter replacements
- Diagnostic scans
6. Be Cautious During Supply Disruptions
With recent shortages and supply chain changes in Australia, fuel quality may vary slightly—so stick to trusted locations.
What To Do If You Suspect Fuel Contamination
Step 1: Stop Driving Immediately
Continuing to drive can spread contamination through the fuel system.
Step 2: Do NOT Restart the Engine
Especially if misfuelling is suspected.
Step 3: Get Professional Diagnosis
Visit an HTR workshop for:
- Fuel testing
- Tank drainage
- Fuel system flush
- Injector and filter inspection
Step 4: Replace Affected Components
In severe cases:
- Fuel filters
- Injectors
- Fuel pumps
Step 5: Document the Incident
If contamination occurred at a fuel station, you may be eligible for compensation.
Fuel contamination is becoming a growing concern in Australia, especially with:
- Ongoing fuel supply disruptions
- Temporary changes to fuel quality standards
- Increased demand and shortages
The key to protecting your vehicle is prevention, awareness, and fast action.
If your car feels “off” after refuelling, don’t ignore it—it could save you thousands in repairs.
Need Help in Melbourne?
If you suspect fuel contamination, visit one of our HTR workshops across Melbourne. Our team uses advanced diagnostics and hands-on expertise to identify and fix fuel-related issues before they escalate.