The search for the best 5W-40 motor oil in 2025 is more than just browsing store shelves or believing advertisements. Modern engines require oils that can withstand high temperatures, protect turbochargers, minimize evaporation, and meet strict OEM approvals. The only reliable way to judge oils is by looking at their Technical Data Sheets (TDS), which reveal measurable performance indicators.
This guide provides a full comparison of ten leading 5W-40 oils (Red Line, AMSOIL, Mobil 1, Motul, Castrol, Shell, Pennzoil, Valvoline, Liqui Moly). Instead of marketing language, we compare actual data: HTHS viscosity, Noack volatility, kinematic viscosity, TBN, pour point, flash point, and OEM specifications.
Quick Answer: The winner is Red Line Euro-Series 5W-40, with the highest HTHS (4.3), lowest Noack (6%), and superior ester-based formulation.
What Does 5W-40 Mean?
- 5W: Indicates winter rating. Oil remains pumpable at about –30 °C.
- 40: Indicates thickness at 100 °C (engine operating temp).
5W-40 oils are extremely popular in Europe and colder climates. They ensure smooth cold starts and strong protection under heat.
A Short History of Motor Oils
- Early 1900s: Single-grade oils (SAE 30/40). Poor cold flow.
- 1950s–1960s: Additives like detergents and anti-wear zinc introduced.
- 1970s: Multigrade oils like 10W-40 became common.
- 1980s–1990s: Fully synthetic oils (PAO, ester) entered mainstream.
- 2000s–today: Stricter emissions, turbo engines, and DPFs created demand for oils like 5W-40, which balance cold-start fluidity with high-temp stability.
How We Evaluate Oils (Why These Parameters Matter)
- HTHS (High Temperature High Shear):
Measures oil’s ability to resist thinning under extreme stress. Higher = better. - Noack Volatility:
Measures evaporation loss at 250 °C. Lower = less oil consumption and deposits. - Kinematic Viscosity (KV100):
Indicates oil thickness at operating temperature. - TBN (Total Base Number):
Shows reserve alkalinity to neutralize acids. - Pour Point:
Lowest temperature where oil still flows. - Flash Point:
Indicates resistance to vaporization and burning. - OEM Approvals:
MB 229.5/229.51, BMW LL-01, VW 502/505, Porsche A40, ACEA A3/B4, ACEA C3.
These tests are standardized by ASTM and ACEA:
- ASTM D445 (viscosity),
- ASTM D4683 (HTHS),
- ASTM D5800 (Noack),
- ASTM D2896 (TBN).
Comparison Table of the Best 5W-40 Oils in 2025
| Oil (5W-40) | KV100 (cSt) | HTHS (mPa·s) | Noack (%) | Pour Point (°C) | Flash Point (°C) | TBN | OEM / Notes | Protection Index* |
|---|---|---|---|---|---|---|---|---|
| Red Line Euro-Series | 15.2 | 4.3 | 6 | –45 | — | — | Ester base, A3/B4 style | 83 |
| AMSOIL Euro FS | 14.3 | — | 10 | –40 | 224 | — | Long-drain, Euro OEM | 50† |
| Motul 8100 X-Cess Gen2 | 13.5 | 3.8 | — | –45 | 228 | 10.2 | MB 229.5, BMW LL-01, Porsche A40 | 30† |
| Mobil 1 ESP Formula M | 13.4 | 3.8 | — | –39 | 236 | — | MB 229.51 (DPF safe) | 30† |
| Castrol EDGE A3/B4 | 14.1 | 3.7 | 11 | –45 | 210 | — | Fluid Titanium | 26 |
| Shell Helix Ultra | 13.1 | 3.68 | — | –39 | 215 | — | GTL base | 18† |
| Liqui Moly Molygen | 14.0 | ≥3.5 | 10 | –45 | 230 | 11.3 | High TBN, friction modifiers | 15 |
| Valvoline SynPower MST | 14.0 | — | — | –45 | 232 | 7.8 | Mid-SAPS C3 | — |
| Mobil 1 FS X2 | 13.6 | — | — | –45 | 227 | — | OEM all-rounder | — |
| Pennzoil Platinum Euro | 13.3 | — | — | –45 | 215 | — | GTL PurePlus | — |
*Protection Index = 70% HTHS + 30% Noack. Missing data scored conservatively (†).
Detailed Analysis of Each Oil
Red Line Euro-Series 5W-40
Ester-based, high HTHS (4.3), lowest Noack (6%). The best balance for high-performance engines, track driving, and hot climates.
AMSOIL Euro FS 5W-40
Strong long-drain oil, Noack 10%, KV100 14.3. Excellent reputation in Euro applications.
Motul 8100 X-Cess Gen2 5W-40
OEM approvals: BMW LL-01, MB 229.5, Porsche A40, VW 502/505. TBN 10.2 ensures acid control.
Mobil 1 ESP Formula M 5W-40
Low-SAPS formula for DPF cars, MB 229.51 approval. Best for modern diesels.
Castrol EDGE A3/B4 5W-40
Fluid Titanium technology, strong OEM coverage, widely available.
Shell Helix Ultra 5W-40
Produced from GTL (gas-to-liquid). High cleanliness. Slightly lower viscosity than Red Line.
Pennzoil Platinum Euro 5W-40
PurePlus GTL base, high cleanliness focus. Excellent for petrol engines.
Valvoline SynPower MST C3 5W-40
Mid-SAPS oil, safe for DPF and catalytic converters. OEM approved.
Liqui Moly Molygen 5W-40
High TBN (11.3), supports long drains, friction modifiers improve efficiency.
Mobil 1 FS X2 5W-40
Balanced all-rounder, wide OEM approvals.
Myths About Motor Oil
- “Thicker is always better” – not true, too thick harms cold starts.
- “Synthetic oils last forever” – false, additives still deplete.
- “Racing oils are best for daily driving” – wrong, they often lack detergents.
- “Mixing oils is safe” – only in emergencies.
Choosing the Right 5W-40 for Different Drivers
- Performance/turbo cars: Red Line Euro-Series.
- Long-drain intervals: AMSOIL Euro FS.
- German luxury cars: Motul 8100 X-Cess.
- Modern diesel with DPF: Mobil 1 ESP Formula M or Valvoline MST.
- Long-distance drivers: Liqui Moly Molygen.
Extended FAQ
Is 5W-40 always the best?
Not always. Some modern cars require thinner oils (0W-20, 5W-30) for fuel economy.
Is higher HTHS always better?
For performance, yes. But for emissions systems, balance matters.
Can I switch between 5W-40 and 0W-40?
Yes, if OEM allows it. Both protect at high temp, but 0W flows better cold.
What’s the difference between ACEA A3/B4 and C3?
A3/B4: High-SAPS, strong film strength. C3: Mid-SAPS, DPF-friendly.
Final Conclusion
Based on data sheet analysis, the best 5W-40 oils in 2025 are:
- Red Line Euro-Series 5W-40 → Best overall, strongest protection.
- AMSOIL Euro FS 5W-40 → Best for long drains and OEM coverage.
- Mobil 1 ESP Formula M 5W-40 → Best for DPF-equipped diesels.
- Motul 8100 X-Cess Gen2 5W-40 → Best OEM-approved balance.
- Castrol EDGE A3/B4 5W-40 → Trusted, affordable, widely available.
Where to Buy
Get your oil from oilteck.com for guaranteed authentic products, fast EU delivery, and expert support.
