We value your privacy
Cookies are small text files stored on your computer by websites you visit. They help users navigate websites efficiently and enable certain essential functions.
Cookies necessary for the website to function properly can be set without your consent, while all other cookies require your approval before being used in your browser.
Additionally, we use cookies to gather data for personalizing and evaluating the effectiveness of our advertising.
For more information, please refer to the Google Privacy Policy.
You can find the list of all the cookies that we use on our website here.
Years in Business
Litres of Stock
9001:2015 Certified
Counties Served
HDDO, or Heavy Duty Diesel Oil, is engine oil developed specifically for the high loads, extended drain intervals and emissions-control systems found in modern diesel trucks, buses and commercial vehicles.
Gem Oils supplies HDDO formulated to API CK-4/CI-4 and ACEA E-series specifications, alongside relevant OEM approvals, for fleets running diesel particulate filters and selective catalytic reduction systems.
Heavy-duty diesel engines generate significant soot loading and sustained high operating temperatures. HDDO is built to control wear from this soot and resist oxidation, helping protect the engine across extended service intervals.
Controls soot-related wear and oxidation under sustained heavy load.
Formulated to recognised API and ACEA heavy-duty diesel specifications.
Built for trucks, buses and commercial vehicles operating extended duty cycles.
Our technical team will confirm the right grade for your fleet before you order.
Always check the required product type, grade, specification and compatibility against the vehicle or equipment manufacturer’s recommendations before use.
Answers to the questions we are most commonly asked by garages, fleet operators, and motor factors. For vehicle-specific advice, contact our technical team directly.
HDDO stands for Heavy Duty Diesel Oil. It is the category of engine lubricant developed for trucks, buses and commercial vehicles operating under sustained high load. HDDO products are formulated to control soot-related wear and resist oxidation under the demanding conditions of commercial fleet operation.
Yes. Gem Oils HDDO products are formulated to be compatible with modern emissions after-treatment systems, including diesel particulate filters (DPF) and selective catalytic reduction (SCR). Always check the specific product data sheet against your engine manufacturer’s requirement to confirm the correct product.
No. HDDO is formulated for heavy-duty diesel applications. For cars and light commercial vehicles, the correct product is from our Passenger and Light Commercial Oil range. Contact our technical team if you are unsure which category applies to your vehicle.
HDDO is available in drum and bulk formats suited to fleet and haulage operations. Contact Gem Oils on +353 49 437 8116 or [email protected] for current pack sizes and to arrange delivery across Ireland.
Tell us the equipment, application and the grade or specification required. Our team can help identify suitable Gem Oils options and available pack sizes.
