ACEA C3 vs. C2 vs. C4: Which Oil Do You Need?

Use the ACEA category specified for the engine. C2, C3, and C4 are different aftertreatment-compatible oil categories — not a good-better-best sequence.

In ACEA’s 2023 light-duty sequence, C2 uses lower HTHS viscosity than C3, while C4 combines C3-level HTHS with a lower sulfated-ash ceiling. Those differences affect fuel economy, oil-film behavior, and aftertreatment compatibility.¹

For a single-category explanation, see What Is ACEA C3 Engine Oil?.

What are the key numeric differences?

ACEA 2023 property	C2	C3	C4
HTHS viscosity at 150°C	≥2.9 and <3.5 mPa·s	≥3.5 mPa·s	≥3.5 mPa·s
Sulfated ash	≤0.8%	≤0.8%	≤0.5%
Phosphorus	0.07–0.09%	≤0.09%	≤0.09%
Sulfur	≤0.3%	≤0.2%	≤0.2%
TBN requirement	No minimum in the main table	≥6.0 mgKOH/g by ASTM D2896	≥4.0 mgKOH/g by ASTM D4739

These values are only part of each category. Full compliance also requires the applicable engine and laboratory tests.

What is ACEA C2?

C2 is an aftertreatment-compatible category with lower HTHS viscosity intended to provide fuel-economy capability in engines designed for it. Its lower HTHS range is not suitable for an engine that requires C3-level viscosity unless the OEM explicitly permits C2.

What is ACEA C3?

C3 is an aftertreatment-compatible category with HTHS of at least 3.5 mPa·s and a sulfated-ash limit of 0.8%. It is common in European oils carrying selected BMW, Mercedes-Benz, Volkswagen, Porsche, GM, or other OEM claims.

C3 itself is not any one of those approvals.

What is ACEA C4?

C4 retains an HTHS minimum of 3.5 mPa·s but reduces the sulfated-ash limit to 0.5%. It has its own chemistry and test profile and is associated with selected manufacturer requirements.

Do not replace C3 with C4 because C4 has less ash. Lower ash is not a universal upgrade.

Can C2 and C3 both appear on one oil?

Some product sheets list both categories. That requires careful review because C2 and C3 have different HTHS ranges in the current sequence. The claim may involve viscosity-specific variants, different sequence editions, or supplier documentation that needs clarification.

MANNOL Energy Premium 5W-30’s supplied 2026 sheet lists both ACEA C2 and C3. Before using that dual claim in customer-facing content, confirm the current manufacturer TDS, sequence year, and test basis.

Does the vehicle’s OEM specification matter more?

The ACEA category and the OEM specification both matter. The OEM specification can require an ACEA baseline plus manufacturer-specific engine tests, chemical limits, or approval.

A vehicle requiring BMW Longlife-04, MB 229.51, VW 507.00, Renault RN0720, or another standard should not be serviced from the ACEA letter alone.

Which active Inforca products are relevant?

As of September 2026, Inforca lists several MANNOL European-positioned oils.²

• MANNOL Energy Premium 5W-30, MN7908: supplied sheet lists ACEA C2/C3 and several OEM claims.
• MANNOL Energy Formula PD 5W-40, MN7913: supplied sheet lists ACEA C3 and several OEM recommendations.
• MANNOL Formula Excel 5W-40, MN7923: supplied sheet lists ACEA C3 and several OEM claims.
• MANNOL Energy Ultra JP 5W-20: supplied sheet lists ACEA C5, not C2/C3/C4.

These are not interchangeable. Confirm the exact requirement and claim status.

How should a shop select among C2, C3, and C4?

1. Identify the VIN and engine code.
2. Find the exact OEM oil standard.
3. Confirm the ACEA category and sequence edition.
4. Confirm the SAE viscosity.
5. Compare the exact product TDS.
6. Verify formal approval where required.
7. Use the vehicle’s drain interval.

Frequently asked questions

Is C3 better than C2?

C3 is not better than C2: C3 has higher HTHS, while C2 can support fuel economy in engines designed for its lower HTHS range.

Is C4 better for a DPF than C3?

C4 has a lower ash limit, but it is correct only where the OEM specifies or permits C4.

Can I use C3 when the manual says C2?

Only if the OEM explicitly allows it. Higher HTHS can affect efficiency and operation.

Can I use C2 when the manual says C3?

Do not do so without explicit OEM permission; C2’s HTHS range is lower.

Does 5W-30 identify the ACEA category?

A 5W-30 grade does not identify the ACEA category; multiple ACEA categories can use 5W-30.

Send the complete oil requirement

Send Inforca the VIN, engine code, OEM specification, ACEA category, viscosity, current oil, service volume, and package size. The team can screen documented products and confirm the current technical sheet.

Sources

Footnotes

1. ACEA, 2023 Oil Sequences for Light-Duty Engines, accessed September 10, 2026. ↩

2. Inforca International, MANNOL Active Product Families, accessed September 10, 2026. ↩