As the name suggests, Gulf Western Oil’s TOP DOG range is a dominant player in the diesel engine oil market. Renowned for high performance in heavy-duty farming machinery, this range of Australian-made oils have been a popular choice in the agricultural sector. 

Synonymous with toughness,  the TOP DOG HDZ-50 20W-50 boasts a high viscosity formulation that translates to less oil consumption and better wear protection for engines working in severe applications such as those seen in agriculture. 

The premium mineral diesel engine oil is an ideal mixed fleet oil as it can be used in heavy-duty diesel engines, stationary engines, commodity transport applications, 4WD’s as well as petrol engine applications requiring API (Automotive Performance Institute) SL or earlier performance levels. 

Importantly, the Gulf Western Oil TOP DOG HDZ-50 20W-50 uses API and OEM approved additive technology that suits American, European and Japanese diesel engines.  

Other significant benefits include superior sludge and soot control, which makes for cleaner engines and performance, improved oil pressure – both at idle and under load – and an additional seal conditioner that helps rejuvenate seals and gaskets to slow or prevent oil leaks. The TOP DOG HDZ-50 20W-50 is also formulated for turbo charged engines and those fitted with exhaust gas recirculation (EGR) systems. 

In line with Gulf Western Oil’s reputation and other product offerings, the TOP DOG uses premium quality base oil and best-in-class additive technology to ensure dependability in the field. The product has been made to withstand harsh Australian agricultural conditions and the rigours of heavy-duty diesel engines in these applications, providing agricultural businesses with what they need most – uptime.

This was the mission of Peter Vicary in 1988 when he founded Gulf Western Oil – to design oils specific to Australian conditions and suitable to a wide range of applications. Which is exactly what the TOP DOG HDZ-50 20W-50 is – a versatile, reliable diesel oil for mixed fleets that helps industrial businesses keep their lubricant inventory to a minimum.

Beginning as a small company, today Gulf Western Oil is Australia’s largest family-owned lubricants manufacturer. Operating out of the Southern Hemisphere’s most advanced ISO-certified facility, Gulf Western Oil uses the latest in blending technology to achieve precise specifications and consistency. It is one of the key reasons the products have proved so reliable to Australian customers. 

As a key strategic supply partner of Motion Australia, customers can access the Gulf Western Oil TOP DOG range from their local Motion Australian branch. As Australia’s largest distributor of industrial lubricant products, Motion Australia experts can advise as to which engines this range or other oils in the Gulf Western Oil portfolio are suited to specific agricultural machinery.

Summary of benefits

• High viscosity formulation offers higher levels of wear protection and reduced oil consumption

• Improved oil pressure at idle and under load

• Formulated for turbo charged engines and those fitted with Exhaust Gas Recirculation (EGR) systems. 

• Superior sludge and soot control for a cleaner engine

• Additional seal conditioner to rejuvenate seals and gaskets to slow or stop oil leaks

• Suitable for heavy towing and/or operation in high ambient temperatures

• Suitable for high mileage trucks, 4WD and utes

• Not suitable for vehicles with Diesel Particulate Filters (DPFs


The additive technology used in TOP DOG HDZ-50 20W-50 meets and exceeds the following performance specifications:
• SAE Viscosity 20W-50


• ACEA E7 

• Allison C4

• Caterpillar ECF-2, TO-2

• Cummins 20078

• Global DHD-1


• Mack EO-N Premium Plus

• MAN 271, 3275

• Mercedes-Benz sheet 228.3, 229.1

• MTU Type 1, Type 2

• Volvo VDS-3