Caterpillar 15W-40 Engine Oil Specifications: CI-4, Applications and Pack Sizes
Cat DEO 15W-40 is Caterpillar diesel engine oil developed for applicable heavy-duty engines. The product sold by MAK Group as Cat part 3E-9848 is a 20-litre pail carrying the CI-4 performance level.
What the specification means
| Item | Product information |
|---|---|
| Product | Cat Diesel Engine Oil (DEO) |
| SAE grade | 15W-40 |
| API category | CI-4 PLUS / CI-4 and earlier categories listed by Caterpillar |
| Cat part number | 3E-9848 |
| Pack size | 20 litres |
The SAE grade describes viscosity behavior. The API category describes a performance level. A correct choice must satisfy both—and any additional Caterpillar requirement in the engine manual.
Which engines is CI-4 intended for?
Caterpillar’s product information positions this DEO formulation for applicable Tier 3 and earlier engines without aftertreatment devices. That makes the emissions configuration important. A newer engine with a diesel particulate filter or another aftertreatment system can require a newer low-ash oil category.
Why “15W-40” alone is not enough
Many diesel oils share the same viscosity but use different additive systems and approvals. Before ordering, record:
- Machine and engine model
- Serial number
- Emissions tier and aftertreatment equipment
- Required API category or Cat fluid recommendation
- Ambient-temperature range and service duty
Typical applications
When the manual confirms the same grade and category, Cat DEO 15W-40 can serve construction equipment, generator sets and other heavy-duty diesel engines. The equipment manual remains the final authority; this guide does not replace model-specific service information.
Pack size and part-number check
The 20L pail is useful for scheduled equipment service, but always compare the part number and label before use. Caterpillar sells lubricants in different pack sizes and regional configurations, so the pack description should not be used as the only identity check.
Frequently asked questions
Can CI-4 be used in a new engine with a DPF?
Do not assume so. Check the engine manual; aftertreatment systems often require a newer, lower-ash category.
Can Cat DEO be used in non-Cat equipment?
Only if the other manufacturer permits the same viscosity and performance requirements.
Is this oil for transmissions or hydraulics?
No. DEO is diesel engine oil. Use the specified compartment fluid for transmissions and hydraulic systems.
View Cat DEO 15W-40 CI-4, 20L or browse diesel and heavy-duty engine oils.
الخلاصة: طابق 15W-40 وCI-4 مع موديل المحرك ونظام الانبعاثات. العبوة المعروضة 20 ليتر ورقمها 3E-9848.
Technical review and sources
Reviewed by: MAK Group Lubrication Specialists. Last reviewed July 23, 2026.
Always confirm the exact vehicle or equipment manual, model year, engine or compartment and current manufacturer specification before use.
