Castrol Magnatec 5W-30 C3 is a 1-litre bottle of fully synthetic engine oil from Castrol’s Magnatec range, positioned as an everyday, OEM-friendly oil for modern petrol and diesel cars. It competes with similar mid-tier synthetics from brands like Mobil, Shell and Total, especially where manufacturers call for a low-SAPS “C3” oil to suit emissions hardware.

Is 5W-30 C3 the right oil for your car?

“5W-30” points to a viscosity that flows well when cold for easier starts, while still offering protection once up to temperature. The “C3” part matters if your vehicle has a diesel particulate filter (DPF) or a catalytic converter that benefits from reduced ash content — but it’s only a match if your handbook specifies ACEA C3 (and any required OEM approvals).

• 1L size: useful for top-ups between services or keeping in the boot.
• ACEA C3: commonly specified for DPF-equipped diesels and many modern petrol engines.