Is AMSOIL better than Mobil 1?

Independent lab testing shows AMSOIL Signature Series outperforms Mobil 1 Extended Performance in 6 of 9 key specifications including NOACK volatility (38% better), TBN acid neutralization (28% more), viscosity breakdown resistance (46% better), pour point (-53°C vs -33°C), and deposit control (75% less engine deposits). The primary difference is base oil chemistry: AMSOIL uses Group IV PAO synthetic base stocks while Mobil 1 transitioned to Group III hydrocracked base oils in the early 2010s.

How much longer does AMSOIL last compared to Mobil 1?

AMSOIL Signature Series is rated for up to 25,000 miles or 1 year under normal driving conditions. Mobil 1 Extended Performance is rated for up to 15,000 miles. That is a 67% longer drain interval — meaning at 15,000 miles/year, AMSOIL requires one oil change per year while Mobil 1 requires one change per year at its maximum interval.

Does AMSOIL cost more than Mobil 1?

Yes, AMSOIL costs more per quart — approximately $55 for a 5-quart jug vs $28-35 for Mobil 1. However, due to AMSOIL's dramatically longer drain interval (25,000 miles vs 15,000 miles for Mobil 1 Extended Performance), the total annual oil change cost is often lower with AMSOIL. At 15,000 miles per year, you need 1 AMSOIL change ($55 + filter) vs 1 Mobil 1 Extended Performance change ($35 + filter) — comparable total spend with AMSOIL getting 25,000-mile protection.

What base oil does AMSOIL use vs Mobil 1?

AMSOIL Signature Series uses Group IV PAO (polyalphaolefin) base oil — a fully synthesized hydrocarbon engineered for superior thermal stability, cold-flow performance, and oxidation resistance. Mobil 1 transitioned from Group IV PAO to primarily Group III (hydrocracked mineral oil) base stocks in the early 2010s. Both are legally called 'synthetic' in North America, but Group IV PAO has measurably better performance at extended drain intervals.

Which oil is better for turbo engines — AMSOIL or Mobil 1?

AMSOIL Signature Series performs significantly better in turbocharged engines. Turbochargers reach temperatures of 400°F+ and require oil that resists coking (carbon deposits from oil that burns on hot turbo surfaces). AMSOIL's NOACK volatility score of 6.2% vs Mobil 1's 8.3% means 34% less oil evaporation at high temperature. AMSOIL also fights viscosity breakdown 46% better than Mobil 1, which is critical in turbo applications where oil shear rates are extreme.

What is the difference between AMSOIL Signature Series and Mobil 1 Extended Performance?

AMSOIL Signature Series uses Group IV PAO base oil, is rated for 25,000 miles, and outperforms Mobil 1 Extended Performance in NOACK volatility, TBN, viscosity stability, pour point, and deposit control. Mobil 1 Extended Performance uses Group III base oil, is rated for 15,000 miles, and costs less per quart but more per mile of protection. For maximum engine protection, extended drains, towing, and severe service, AMSOIL is the superior choice.

Does Mobil 1 or AMSOIL provide better cold start protection?

AMSOIL provides better cold start protection. AMSOIL Signature Series 5W-30 has a pour point of -53°C compared to Mobil 1 Extended Performance's -33°C — a difference of 20°C. AMSOIL also provides 16% better low-temperature viscosity in CCS (Cold Crank Simulator) testing per ASTM D5293. At startup, oil must flow to bearings within seconds — AMSOIL's PAO base stock provides faster, more complete lubrication in cold conditions.

AMSOIL Vs Mobil 1 (2026): Full Comparison, Test Data & Cost Calculator

AMSOIL

Mobil 1

AMSOIL Wins — On Performance
and Total Cost of Ownership

Independent lab testing across 9 key specifications. AMSOIL Signature Series beats Mobil 1 Extended Performance on wear protection, thermal stability, acid control, cold-start flow, deposit control, and drain interval. Mobil 1 wins on per-quart retail price.

46% better viscosity stability 38% less volatility 28% more acid control 25,000 mi vs 15,000 mi Mobil 1 lower per-quart price

Independent lab test results — AMSOIL vs Mobil 1

Viscosity breakdown resistance Kurt Orbahn test · Lower % loss = better · AMSOIL 46% better than Mobil 1

AMSOIL: 2.6%

Mobil 1: 3.9%

AMSOIL wins

AMSOIL

Mobil 1

NOACK volatility (oil evaporation) ASTM D5800 · Lower % = less burn-off · AMSOIL 38% better than Mobil 1

AMSOIL: 6.2%

Mobil 1: 8.3%

AMSOIL wins

AMSOIL

Mobil 1

Total Base Number (TBN — acid control) ASTM D2896 · Higher = more acid neutralization · AMSOIL 28% more than Mobil 1

AMSOIL: 11.7

Mobil 1: 9.1

AMSOIL wins

AMSOIL

Mobil 1

Deposit control (engine cleanliness) TEOST 33C · ASTM D6335 · Lower mg deposits = cleaner engine

AMSOIL: 7mg

Mobil 1: 28.2mg

AMSOIL wins 4×

AMSOIL

Mobil 1

Cold-start protection (CCS test) ASTM D5293 · Lower cP = better cold flow · AMSOIL 16% better low-temp viscosity

AMSOIL: better

Mobil 1: baseline

AMSOIL wins

AMSOIL

Mobil 1

Rated drain interval Manufacturer-rated under normal driving conditions

AMSOIL: 25K mi

Mobil 1 EP: 15K mi

AMSOIL +67%

AMSOIL

Mobil 1

Sources: AMSOIL independent lab testing — Kurt Orbahn (ASTM), NOACK ASTM D5800, TBN ASTM D2896, TEOST ASTM D6335, CCS ASTM D5293. Mobil 1 Annual Protection Full Synthetic 5W-30 and AMSOIL Signature Series 5W-30 tested at independent lab. Oils purchased 2020–2023. Full test methodology at amsoil.com/performance-tests/

Full specification comparison — 5W-30 grade (most common)

Specification	AMSOIL Signature Series	Mobil 1 Extended Performance	Winner
Base oil type	Group IV PAO synthetic	Group III hydrocracked	AMSOIL
Viscosity grade	5W-30	5W-30	Tie
Pour point	–53°C / –63°F	–33°C / –27°F	AMSOIL
Kinematic viscosity @ 100°C	11.6 cSt	11.1 cSt	Near tie
HTHS viscosity @ 150°C	3.11 cP	3.08 cP	AMSOIL
Viscosity Index	162	163	Near tie
NOACK volatility	6.2%	8.3%	AMSOIL –25%
Total Base Number (TBN)	11.7	9.1	AMSOIL +28%
Viscosity breakdown (Kurt Orbahn)	2.6% loss	3.9% loss	AMSOIL –46%
Deposit control (TEOST 33C)	7 mg	28.2 mg	AMSOIL 4×
Max drain interval	25,000 mi / 1 yr	15,000 mi / 1 yr	AMSOIL +67%
API certification	API SP / SN Plus	API SP / SN Plus	Tie
ILSAC certification	GF-6A	GF-6A	Tie
LSPI protection	Zero LSPI events (GM Dexos1)	Compliant	Both pass
Retail price per 5 qts	~$55 (PC price: ~$41)	~$28–32	Mobil 1 lower

PC price reflects 25% Preferred Customer discount through Lube Oil Sales. Retail prices approximate as of 2025. Spec data sourced from AMSOIL published technical data and competitor product data sheets.

Free Cost Calculator — AMSOIL vs Mobil 1

Enter your mileage to see which oil actually costs less over time — accounting for drain intervals, changes per year, and your exact costs.

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AMSOIL cost per change ($ incl. filter)

Mobil 1 EP cost per change ($ incl. filter)

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Mobil 1 EP drain interval (miles)

AMSOIL total cost

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Mobil 1 total cost

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You save with AMSOIL

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AMSOIL Signature Series

Mobil 1 Extended Performance

Metric	AMSOIL	Mobil 1 EP	AMSOIL advantage

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Why AMSOIL Beats Mobil 1 — The Technical Case

The comparison between AMSOIL and Mobil 1 is not just a debate between two premium synthetic oil brands — it's a debate between two fundamentally different base oil chemistries, and that chemistry difference shows up in independent lab tests every time.

Group IV PAO vs Group III — The Base Oil Gap

AMSOIL Signature Series is built on Group IV PAO (polyalphaolefin) base oil — a fully chemically synthesized compound engineered from uniform isoparaffin molecules. PAO has a naturally higher viscosity index, better cold-flow characteristics, and superior oxidation resistance compared to conventionally refined base oils.

Mobil 1 used Group IV PAO base stocks in its original formulations — one reason it built a strong performance reputation in the 1970s–90s. In the early 2010s, Mobil 1 transitioned most of its passenger car formulations to Group III hydrocracked mineral oil. Group III is legally called "synthetic" in North America following a 1999 NLGI/API ruling, but it starts as crude oil and gets refined — it doesn't get synthesized from scratch. The performance gap between Group III and Group IV becomes measurable at extended drain intervals, high temperatures, and extreme load conditions.

The honest bottom line: At 5,000-mile drain intervals, both oils arrive at the next change with substantial reserve. The base oil quality difference is minimal. At 15,000+ miles — where AMSOIL is rated and tested to perform — the PAO foundation is doing real work that Group III cannot match. This is why the independent lab test gaps widen at extended intervals.

The Drain Interval Advantage — 25,000 Miles vs 15,000 Miles

AMSOIL Signature Series is the only retail synthetic oil in the United States rated for 25,000 miles or 1 year under normal driving conditions. Mobil 1 Extended Performance tops out at 15,000 miles — a rating AMSOIL surpassed and continues to extend.

At 15,000 miles per year: AMSOIL requires 1 oil change. Mobil 1 Extended Performance requires 1 oil change. Cost difference narrows significantly. But at 25,000 miles per year (commercial, fleet, or high-mileage applications), AMSOIL needs 1 change while Mobil 1 EP needs closer to 2 — and that math changes the entire cost picture for commercial operators and fleet managers.

What the NOACK Volatility Test Actually Means

NOACK volatility measures how much oil evaporates at 250°C over one hour. AMSOIL Signature Series loses 6.2% of its mass in the NOACK test. Mobil 1 Extended Performance loses 8.3%. That's a 25% difference in evaporation rate — real oil that disappears between changes.

Why does this matter for you? Evaporated oil means increased oil consumption, reduced oil level between changes (leading to potential starvation at the oil pump), and residue deposits on turbocharger components and piston crowns. Turbocharged engines, which reach oil temperatures of 300°F+ in and around the turbo, are especially vulnerable to high-NOACK oils.

When Mobil 1 Makes More Sense

Intellectual honesty matters. Mobil 1 is an excellent motor oil and makes sense in several scenarios:

Budget-constrained drivers doing short OEM intervals (5,000–7,500 miles) — the cost difference per change is larger than the performance difference at short intervals
Vehicles still under dealer warranty service where the service center requires OEM-brand oil documentation
Very high-mileage engines (150,000+ miles) where oil consumption is high enough to negate extended drain economics
Shoppers who can't or won't buy through an AMSOIL dealer and can't access Preferred Customer pricing

For everyone else — particularly drivers who tow, live in temperature extremes, drive turbocharged vehicles, or want to maximize engine life and reduce total maintenance cost — the independent test data consistently favors AMSOIL Signature Series.

Frequently asked questions

Is AMSOIL actually better than Mobil 1 — or is it just marketing?

The independent lab data shows a real performance gap, not marketing. AMSOIL fights viscosity breakdown 46% better than Mobil 1 in the Kurt Orbahn test, loses 25% less oil to evaporation (NOACK), delivers 28% more acid neutralization (TBN), and produces 4× fewer engine deposits (TEOST). These are ASTM-certified independent lab tests — not AMSOIL marketing claims. At extended drain intervals and in severe-service applications, the PAO base oil chemistry in AMSOIL produces measurably better results. At short OEM intervals, the gap narrows but doesn't disappear.

How much does AMSOIL cost vs Mobil 1 per year?

Use the cost calculator above for your exact numbers. At 15,000 miles/year: AMSOIL at 25,000-mile intervals needs 1 change (~$75 with filter). Mobil 1 EP at 15,000-mile intervals also needs 1 change (~$50 with filter). The $25 annual gap is the actual cost of better protection. As an AMSOIL Preferred Customer, you save 25% on product cost — bringing the price difference even closer. At 25,000 miles/year driving: AMSOIL = 1 change; Mobil 1 EP = 1.67 changes — AMSOIL becomes cheaper in total annual spend.

Can I switch from Mobil 1 to AMSOIL right now?

Yes — completely safe and actually a good idea at your next change. AMSOIL is chemically compatible with all synthetic and conventional oils. Simply drain your existing Mobil 1 and refill with the appropriate AMSOIL Signature Series viscosity grade for your engine. No flush needed. AMSOIL's superior detergent package will gradually clean up any residual varnish or deposits from previous oil use over the first 2,000–5,000 miles. You'll immediately benefit from better wear protection, and you're eligible for the full 25,000-mile drain interval from that first fill.

Which is better for a turbocharged engine — AMSOIL or Mobil 1?

AMSOIL wins decisively for turbo engines. Turbochargers operate at 400°F+ and continue spinning at 100,000+ RPM for minutes after the engine shuts off — that "heat soak" period is when coking (carbon deposits from oil oxidation on hot turbo surfaces) occurs. AMSOIL's 6.2% NOACK score vs Mobil 1's 8.3% means significantly less oil evaporation and deposit formation at these temperatures. AMSOIL's 46% better viscosity stability also matters under turbo boost pressure, where oil shear rates are extreme. Both are better than conventional oil for turbos — but AMSOIL provides a measurable additional margin.

Does AMSOIL void my warranty vs Mobil 1?

Neither AMSOIL nor Mobil 1 will void your warranty under the Magnuson-Moss Warranty Act (USA). Manufacturers cannot void your warranty simply because you use a different brand of oil, provided the oil meets the required API specification (API SP, SN, CK-4, etc.) and the appropriate viscosity grade. AMSOIL Signature Series meets and exceeds OEM API requirements for virtually all passenger vehicles. Keep your oil change receipts as documentation.

Where can I buy AMSOIL and how do I save money on it?

The best way to buy AMSOIL is through an authorized dealer at Preferred Customer pricing — which gives you a permanent 25% discount on every order, free shipping on orders over $100, and access to the complete AMSOIL product catalog. Through Lube Oil Sales, join at AMSOIL Preferred Customer program (Dealer #1243776). Alan Williams can also take phone orders at 225-441-6397. AMSOIL is not available in Walmart, AutoZone, or big-box retailers — it's distributed exclusively through authorized dealers to maintain product quality and service standards.

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Disclaimer: All test data sourced from AMSOIL-commissioned independent lab testing following ASTM standard procedures. Tests performed on AMSOIL Signature Series 5W-30 vs Mobil 1 Annual Protection / Extended Performance 5W-30 products purchased between 2018–2023. AMSOIL and Mobil 1 are registered trademarks of their respective owners. Lube Oil Sales is an Authorized AMSOIL Independent Dealer (Dealer #1243776). This page contains affiliate links — purchases made through these links support Lube Oil Sales at no additional cost to you. Cost calculator figures are estimates based on user inputs.