Head-to-Head · Full-Synthetic 5W-40

Rotella T6 vs Delvac 1 ESP: Shell vs Mobil 5W-40

Rotella T6 vs Delvac 1 ESP is the matchup most drivers ask about: Shell's and Mobil's full-synthetic heavy-duty diesel oils, on most truck stop shelves and fleet supply lists across North America. The fair fight is 5W-40 against 5W-40, because that's the grade both are sold in. Here they are side by side, straight from each maker's own data sheet, with no brand spin.

Last reviewed: October 2026 · Sources: Shell Rotella T6 5W-40 technical data sheet (v1.8, 05/2024), Mobil Delvac 1 ESP 5W-40 product data sheet (03/2020), AMSOIL data sheet G3467

Rotella T6 vs Delvac 1 ESP: there's no clear winner. Both are full-synthetic API CK-4 5W-40 oils that list Cummins CES 20086, Detroit DFS 93K222, Mack EOS-4.5 and Volvo VDS-4.5. Delvac 1 ESP lists more named OEM approvals (MB 228.31, MTU) and a higher TBN. Rotella T6 adds Allison TES 439 and is easier to find at truck stops. Pick the one your engine's spec and your supplier support. If you want more margin than either, AMSOIL Max-Duty 5W-40 (DEO) publishes a higher HTHS than Delvac 1 ESP and better cold cranking than both.

Shop AMSOIL DEO 5W-40 → See the spec-by-spec table ↓

CK-4

Both Oils
API Category

5W-40

Grade
Compared

Draw

Overall
Verdict

OEM

Drain Interval
Both Oils

No 15W-40 Delvac 1 ESP

Delvac 1 ESP comes in 5W-40 and 0W-40

Spec by Spec

Rotella T6 vs Delvac 1 ESP: Specs Compared

On the specs a Class 8 engine actually calls for, Rotella T6 5W-40 and Delvac 1 ESP 5W-40 match: both list Cummins CES 20086, Detroit DFS 93K222, Mack EOS-4.5, Volvo VDS-4.5 and Caterpillar ECF-3. The differences are in the extras each one lists, and in the numbers each maker chooses to publish.

Spec	Rotella T6 5W-40	Delvac 1 ESP 5W-40
API	CK-4, CJ-4, CI-4 Plus	CK-4, CJ-4, CI-4 Plus
Cummins	CES 20086, 20081	CES 20086, 20081 (meets)
Detroit	DFS 93K222, 93K218	DFS 93K222, 93K218 (approved)
Mack	EOS-4.5	EOS-4.5 (approved)
Volvo	VDS-4.5	VDS-4.5 (approved)
Caterpillar	ECF-3, ECF-2	ECF-3 (meets)
Mercedes / DTFR	DTFR 15C100	MB 228.31 (approved)
Allison	TES 439	Not listed
MTU / MAN	MAN M 3575	MTU Cat 2.1, MAN M 3575 (approved)
ACEA	E9, E11	E7, E9

"Approved" vs "lists": Mobil splits its data sheet into approvals (Detroit, Mack, Volvo, MB, MTU, MAN) and specs it meets (Cummins, Caterpillar). Shell lists everything under one heading, "Specifications, Approvals & Recommendations." If your warranty or lease needs a registered or approved oil, check that OEM's own list, not just the bottle.

By the Numbers

Typical Properties: T6 vs Delvac 1 ESP vs AMSOIL

Typical properties from each maker's data sheet, all 5W-40. Delvac 1 ESP has the higher TBN; Rotella T6 has the lower pour point. AMSOIL Max-Duty 5W-40 (DEO) has the highest HTHS of the oils that publish it and the lowest cold-cranking viscosity at −30°C, which means easier winter starts.

Property (5W-40)	Rotella T6	Delvac 1 ESP	AMSOIL Max-Duty (DEO)
Viscosity @ 100°C, cSt	14.9	13.8	15.4
HTHS @ 150°C, cP (higher = thicker film when hot)	Not published	3.8	4.3
Cold cranking @ −30°C, cP (lower = easier start)	6,300	6,510	5,555
TBN, mg KOH/g	10.2	12	10.1
Sulfated ash, %	1.0	1.0	0.99
Pour point	−51°C	−48°C	−43°C (−45°F)

Typical values are not specifications and vary with production. Same ASTM test methods for each row (D445, D4683, D5293, D2896, D874, D97). Shell's 5W-40 data sheet does not list HTHS.

⚠ What the numbers can't tell you. API CK-4 is a pass/fail standard; it doesn't rank oils. Neither Shell nor Mobil publishes a same-test wear result against the other, so anyone telling you one of these two is "way better" is selling brand loyalty, not data.

Buying Decision

Which One Should You Choose?

Both are solid oils for a tractor-trailer run on the OEM interval. Choose on the approval your engine or warranty needs, and on where you can actually buy it.

Choose Rotella T6 When

→ You top up on the road and need it at every truck stop
→ You also want Allison TES 439 listed on the same jug
→ Your shop already stocks Shell
→ You run the OEM interval

Choose Delvac 1 ESP When

→ Your maintenance policy wants named OEM approvals (MB 228.31, MTU)
→ You buy through a Mobil commercial supplier
→ You want the higher published TBN
→ You run the OEM interval

Running 15W-40? There is no Delvac 1 ESP 15W-40. Mobil's synthetic 15W-40 is Delvac Extreme, and Rotella T6 also comes in 15W-40. Compare those two, or AMSOIL Max-Duty 15W-40 (DME), if 15W-40 is what your fleet runs.

A Third Option

Where AMSOIL Max-Duty Fits

Rotella T6 and Delvac 1 ESP are both solid CK-4 oils for trucks run on OEM intervals. AMSOIL Signature Series Max-Duty is the third option for operators who want more margin than the spec requires: 6X more wear protection than Detroit's DD13 scuffing test demands, and up to 76% less oil consumption than API CK-4 allows.

Neither of those is a bad oil, and I won't tell you otherwise. The difference is what you're buying past the spec. Max-Duty lists Cummins CES 20086, Detroit DFS 93K222, Mack EOS-4.5 and Volvo VDS-4.5 on one data sheet, so the same oil covers a mixed fleet of heavy-duty trucks. It's also shipped straight to your shop or yard, so you're not relying on what the truck stop has in stock.

5W-40 vs 5W-40 — Red Seal Tech Pick

AMSOIL Signature Series Max-Duty

5W-40 · DEO · API CK-4

Same grade as T6 and Delvac 1 ESP
HTHS 4.3 · cold cranking 5,555 cP at −30°C
Also lists Allison TES 439 and MB 228.31

Shop DEO 5W-40 →

Most Trucks

AMSOIL Signature Series Max-Duty

15W-40 · DME · API CK-4

CES 20086, DFS 93K222, EOS-4.5, VDS-4.5
HTHS 4.5 for heavy loads in heat
The Red Seal tech pick for most Class 8 engines

Shop DME 15W-40 →

Mixed Fleets & Cold Starts

AMSOIL Signature Series Max-Duty

5W-30 · DHD · API CK-4

One oil for Cummins, Detroit, Mack and Volvo specs
Cold cranking to −30°C (−22°F)
The grade AMSOIL ran in the DD13 scuffing test

Shop DHD 5W-30 →

Drain Intervals

Need More Than an OEM-Interval Oil?

Then the oil isn't the whole answer; oil analysis is. Any good synthetic can run the OEM interval. Going past it safely takes a lab report on your own truck. International even puts it in writing for the A26: up to 70,000 miles with oil sampling and International's approval.

That's the program I run with fleets. Keep your current interval, sample at every change, and I go through every report with you. When the data says there's life left in the oil, you move the interval, one truck at a time, on evidence.

Open Your Commercial Account → Get an Oil Analysis Kit →

FAQ

Rotella T6 vs Delvac 1 ESP — Common Questions

From owner-operators, fleet managers, and shop techs choosing a synthetic diesel oil for transport trucks across North America.

Which is better, Rotella T6 or Delvac 1 ESP?

Neither is a clear winner. Both are full-synthetic API CK-4 5W-40 oils that list Cummins CES 20086, Detroit DFS 93K222, Mack EOS-4.5 and Volvo VDS-4.5. Delvac 1 ESP lists more named OEM approvals and a higher TBN; Rotella T6 adds Allison TES 439 and is easier to find at truck stops. Choose on the approval your engine needs and on supply.

Is there a Mobil Delvac 1 ESP 15W-40?

No. Delvac 1 ESP comes in 5W-40 and 0W-40. Mobil's synthetic 15W-40 is Delvac Extreme. Rotella T6 is sold in both 5W-40 and 15W-40, so the fair Rotella T6 vs Delvac 1 ESP comparison is 5W-40 against 5W-40.

Can I use Rotella T6 or Delvac 1 ESP in a Cummins X15?

Yes, where your X15 calls for Cummins CES 20086. Both list CES 20086 on their 5W-40 data sheets. Check your engine manual for the grades it allows.

Do Rotella T6 and Delvac 1 ESP have the same approvals?

They share the core heavy-duty specs: CES 20086, DFS 93K222, EOS-4.5, VDS-4.5 and Caterpillar ECF-3. Delvac 1 ESP also lists MB 228.31 and MTU Category 2.1 approvals. Rotella T6 also lists Allison TES 439 and ACEA E11.

Can either oil be used for extended drain intervals?

Run the OEM interval with either one. Going past it takes oil analysis on your own truck, because idle time, fuel dilution, soot loading and duty cycle all change how long oil lasts. Being synthetic is not enough on its own.

Can Rotella T6 and Delvac 1 ESP be mixed?

Both are CK-4 engine oils, so mixing them for a top-up won't hurt the engine. It does make oil analysis trends harder to read, so go back to one oil at the next change.

How does AMSOIL Max-Duty 5W-40 compare?

AMSOIL Signature Series Max-Duty 5W-40 (DEO) lists the same core specs (CES 20086, DFS 93K222, EOS-4.5, VDS-4.5) plus Allison TES 439 and MB 228.31. On the data sheets it publishes a higher HTHS (4.3 vs 3.8 for Delvac 1 ESP; Shell doesn't publish one for T6) and lower cold-cranking viscosity at −30°C (5,555 cP vs 6,300 and 6,510).

What is the difference between Mobil Delvac 1 ESP and Delvac Extreme?

Mostly the grade. Delvac 1 ESP is Mobil's top synthetic line and comes in 5W-40 and 0W-40. Delvac Extreme is Mobil's synthetic 15W-40. Both are API CK-4 heavy-duty diesel oils, so pick by the viscosity your engine and climate call for.

Is Rotella T6 a good oil?

Yes. Rotella T6 5W-40 is a full-synthetic API CK-4 oil that lists Cummins CES 20086, Detroit DFS 93K222, Mack EOS-4.5, Volvo VDS-4.5 and Allison TES 439. It is a solid choice for a Class 8 engine run on the OEM drain interval, and it's easy to find on the road.

Is Mobil Delvac a good diesel oil?

Yes. Delvac 1 ESP 5W-40 is a synthetic API CK-4 oil with named approvals from Detroit, Mack, Volvo, Mercedes-Benz and MTU, and the highest TBN of the three 5W-40s compared here. Like Rotella T6, it is built for the OEM interval.

Which is better, AMSOIL or Shell Rotella T6?

Both are CK-4 synthetics that list the major OEM specs. AMSOIL Max-Duty publishes test claims Shell doesn't: 6X more wear protection than Detroit's DD13 scuffing test requires and up to 76% less oil consumption than API CK-4 allows, and its 5W-40 (DEO) has better cold cranking at −30°C than T6 5W-40. Rotella T6 is easier to buy at a truck stop. AMSOIL ships direct to your shop or yard.