Your diesel trucking fleet faces demanding highway conditions and tight deadlines. Dennis Oil Company protects your equipment and keeps you on the road with dependable heavy-duty lubricants backed by the latest technological advances. We also supply critical lubricants to agriculture, mining, and heavy construction companies.
Dennis Oil Company’s Kleen-Tech™ heavy-duty diesel engine oils provide outstanding performance. In fact, our unique formula actually improves oil properties over time. It retains its viscosity, for long-lasting anti-friction and anti-wear benefits – even in today’s hotter engines.
Semi-truck engine manufacturers continuously advance and update engine designs, so we keep enhancing our Kleen-Tech technology.
Dennis Oil Company’s advanced heavy-duty diesel engine oils meet the difficult challenges of endurance and fuel economy while extending drain intervals and reducing emissions.
Proven performance
- Meets or exceeds requirements of all major OEM’s.
- Proven technology with millions of miles of testing.
- Up to 53% better wear protection.
- Outstanding control of friction and wear – more than 65% better than the latest API requirements.
- Up to 83% better oxidation control and 63% better deposit control.
- Delivers long-lasting protection and control to help to extend engine and oil life.
- Many customers report fuel savings of 1-3% with synthetic blend 10W-30 CK-4, compared to conventional heavy-duty 15W-40 CK-4 engine oil.
Quality you can trust
All of our engine oils are certified by the American Petroleum Institute, the governing body for engine oils. They all meet or exceed the OEM specifications and some are actually certified by the OEMs directly.
Product List
Our heavy-duty diesel engine oils are available in conventional, semi-synthetic, full-synthetic, and premium-blend to provide extra engine protection.
Conventional
Kleen-Tech 15/40 API CK-4, SN, Formulated to meet or exceed all major brands.
Fleet 15/40 API CK-4, SN, Formulated to meet or exceed all major brands.
Fleet 30, 40 API CF 2-cycle diesel engines (Detroit), hydraulics of heavy equipment 1994 and older, newer to TO-4.
Magnum 30, 40 API CF, Additional additive package (zinc, detergent, etc.) 2 cycle diesel engines (Detroit) hydraulics of heavy equipment 1994 and older, newer TO-4 fluids
NGEO Low Ash 15/40 Meets API CF, CD-natural gas engine calling for .5 ash content.
Synthetic Blend
Kleen-Tech 10/30 API CK-4, Cummins approved, synthetic blend, formulated to meet or exceed all major brands.
Kleen Tech Syn Blend 15/40 API CK-4, Formulated to meet or exceed all major brands.
Premium Products
Magnum XD 15/40 API CK-4 additional additive package for additional soot protection, great for off-road applications, exceeds all major brands.
Magnum XD 10/30 API CK-4, synthetic blend additional additive package for additional soot protection, exceeds all major brands.
Full Synthetic
Heavy-Duty SYN 5/30 meets API CK-4-fully synthetic heavy-duty engine oil, provides additional fuel savings.
Magnum XL 5/40 Meets API CK-4, SN, fully synthetic, exceeds all major brands, provides additional fuel savings.