AMSOIL Direct Jobber · Dealer #1243776 · Tomball, TX · 20+ years running AMSOIL across cars, trucks, motorcycles, diesel fleets, and powersports equipment. I publish independent ASTM lab comparison data not available on other dealer sites.
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.
Sources: AMSOIL independent lab testing — Kurt Orbahn (ASTM), NOACK ASTM D5800, TBN ASTM D2896, TEOST ASTM D6335, CCS ASTM D5293. Full test methodology at amsoil.com/performance-tests/
| 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 2026. Spec data sourced from AMSOIL published technical data and competitor product data sheets.
Enter your mileage to see which oil actually costs less over time — accounting for drain intervals, changes per year, and your exact costs.
| 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 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.
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. Evaporated oil means increased oil consumption, reduced oil level between changes, and residue deposits on turbocharger components and piston crowns.
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.
AMSOIL vs Mobil 1 for High Mileage Engines (75,000+ Miles)
If your engine has crossed the 75,000-mile mark, the AMSOIL vs Mobil 1 decision becomes even more critical — and the performance gap widens significantly.
Why High Mileage Engines Demand More From Their Oil
As engines age, several things happen that put greater demands on motor oil:
- Increased blow-by — worn piston rings allow more combustion gases into the crankcase, increasing oil contamination and acid buildup
- Looser tolerances — worn bearings and cylinder walls create larger clearances, requiring oil with stronger film strength to prevent metal contact
- Seal degradation — aging seals and gaskets become brittle and prone to leaking without proper conditioning
- Higher operating temperatures — carbon deposits reduce heat transfer efficiency, putting more thermal stress on the oil
This is exactly where AMSOIL's higher TBN (Total Base Number) and superior base oil chemistry matter most — not at 5,000-mile drain intervals, but at the extended mileage where wear protection is actively challenged.
TBN: The Most Important Number for High Mileage Engines
TBN (Total Base Number) measures an oil's ability to neutralize acids formed during combustion. Higher TBN = longer protection before the oil is depleted. For a high mileage engine producing more acids from blow-by, this number is critical.
| Metric | AMSOIL Signature Series | Mobil 1 Extended Performance |
|---|---|---|
| TBN (fresh oil) | 11.7 | 9.1 |
| TBN advantage | 28% higher | Baseline |
| Rated drain interval | 25,000 miles | 15,000 miles |
| TBN at drain interval | Still protective | Depleted |
Our Recommendation by Mileage
| Engine Mileage | Recommended AMSOIL Product |
|---|---|
| 75,000 – 100,000 miles | AMSOIL Signature Series 5W-30 |
| 100,000 – 150,000 miles | AMSOIL Signature Series 5W-30 or 10W-30 |
| 150,000+ miles | AMSOIL Signature Series 10W-30 or 10W-40 |
| Diesel high mileage | AMSOIL Diesel All-In-One |
Real World Result
One of our customers — a 2009 Ford F-150 owner from Tomball, TX — switched from Mobil 1 to AMSOIL at 87,000 miles after noticing increased oil consumption. After switching to AMSOIL's 25,000-mile drain interval, his engine is now at 212,000 miles with no leaks, no burning, and compression still within factory spec.
Ready to give your high mileage engine the protection it deserves?
Save 25% — Join as Preferred Customer Shop AMSOIL Products →AMSOIL vs Mobil 1: Which Is Better For Your Vehicle Type?
The right oil depends on more than just brand — it depends on what you're driving. Here's how AMSOIL and Mobil 1 compare across the most common vehicle types.
AMSOIL vs Mobil 1 for Trucks & Towing
Towing and hauling puts extreme thermal stress on motor oil. Engine temperatures spike, oil shear increases, and standard oils can thin out dangerously under load. AMSOIL Signature Series is tested to maintain 47% more film strength than Mobil 1 at high temperatures — critical when you're pulling a trailer at highway speeds.
✔ AMSOIL Wins For:
- Heavy towing (5,000+ lbs)
- Hot climate truck use
- Extended drain intervals
- Diesel trucks
Mobil 1 Is Adequate For:
- Light duty hauling
- Short drain intervals (5-7k miles)
- Mild climate use
Best pick: AMSOIL Signature Series 5W-30 or 0W-40 for trucks and towing applications.
AMSOIL vs Mobil 1 for Motorcycles
Never use standard Mobil 1 in a wet-clutch motorcycle. Standard Mobil 1 contains friction modifiers designed for cars that will cause your wet clutch to slip dangerously. AMSOIL makes motorcycle-specific formulas designed for shared sump engines where the oil lubricates the engine, transmission, and wet clutch simultaneously.
⚠ Important Warning
Mobil 1 Full Synthetic is NOT suitable for most motorcycles with wet clutches. Always use a motorcycle-specific formula. AMSOIL offers dedicated motorcycle oils for V-Twin, metric, and dirt bike applications.
Best pick: AMSOIL V-Twin Synthetic Motor Oil for Harley-Davidson, AMSOIL 10W-40 Synthetic Metric Motorcycle Oil for Japanese bikes.
AMSOIL vs Mobil 1 for Cold Climates
Cold start is when 80% of engine wear occurs — oil has to flow instantly to protect bearings before the engine warms up. Both AMSOIL and Mobil 1 perform well in cold climates, but AMSOIL's cold-temperature pump-ability data shows a consistent edge at extreme temperatures below -30°F.
| Test | AMSOIL 0W-30 | Mobil 1 0W-30 |
|---|---|---|
| Cold Crank at -30°C (cP) | 2,640 | 3,180 |
| Cold Pump at -35°C (cP) | 11,200 | 14,600 |
| Result | Flows faster | Thicker at startup |
Best pick: AMSOIL Signature Series 0W-20 or 0W-30 for cold climate vehicles.
AMSOIL vs Mobil 1 for Diesel Engines
Diesel engines produce significantly more soot and contaminants than gasoline engines, requiring oil with higher detergency and TBN reserve. AMSOIL Diesel All-In-One is purpose-built for diesel applications with a TBN of 13.4 vs Mobil 1 Turbo Diesel Truck's 9.8.
AMSOIL Diesel All-In-One
- TBN: 13.4 (industry leading)
- 25,000-mile drain interval
- Includes fuel additive package
- API CK-4 certified
Mobil 1 Turbo Diesel Truck
- TBN: 9.8
- 7,500-mile drain interval
- No fuel additive
- API CK-4 certified
Best pick: AMSOIL Diesel All-In-One — clear winner for all diesel applications.
AMSOIL vs Mobil 1 for Performance & Track Use
Track days push oil temperatures well beyond normal operating range. At 300°F+ oil temperatures, AMSOIL's NOACK volatility score of 6.6% vs Mobil 1's 10.2% means significantly less oil burn-off under extreme conditions — keeping your oil level stable and your engine protected lap after lap. AMSOIL also achieved zero LSPI events in GM's Dexos1 Gen 2 engine test, critical for modern turbocharged performance engines.
Best pick: AMSOIL Dominator Synthetic Racing Oil for dedicated track use, AMSOIL Signature Series 5W-50 for street/track dual use.
Quick Reference: Best AMSOIL Product By Vehicle Type
| Vehicle Type | Recommended AMSOIL Product | vs Mobil 1 |
|---|---|---|
| Trucks & Towing | Signature Series 5W-30 / 0W-40 | AMSOIL Wins |
| Motorcycles (wet clutch) | V-Twin / Metric Motorcycle Oil | AMSOIL Only |
| Cold Climates | Signature Series 0W-20 / 0W-30 | AMSOIL Wins |
| Diesel Engines | Diesel All-In-One | AMSOIL Wins |
| High Mileage (75k+) | Signature Series 5W-30 / 10W-30 | AMSOIL Wins |
| Performance / Track | Dominator Racing Oil / SS 5W-50 | AMSOIL Wins |
Find the right AMSOIL product for your vehicle and save 25% today.
Save 25% — Join as Preferred Customer Shop All AMSOIL Products →| AMSOIL Signature Series | Mobil 1 Extended Performance | |
|---|---|---|
| Cost per quart | ~$12 (Preferred Customer) | ~$11 |
| Drain interval | 25,000 miles | 15,000 miles |
| Oil changes per 75k miles | 3 changes | 5 changes |
| Total oil cost (5 qts) | $180 | $275 |
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