Deutz DQC III-18 LA vs IV-18 LA: which low-ash oil is on Deutz's list?
DQC III-18 LA and DQC IV-18 LA are Deutz's low-ash engine oil classes. III-18 LA is the standard-quality high-performance class, and IV-18 LA is the ultra-high-performance class for engines with the highest output.[2]
On Deutz's approval list issue 09/2026, Rubia Works 4000 15W-40 is approved to DQC III-18 LA, and Rubia Works 5000 10W-40 and 5000 FE 5W-30 to DQC IV-18 LA, all worldwide.[1]
Published · Updated · How did we check this? · Pack sizes and prices
Approval status at a glance
Four status levels: OEM-approved (OEM list); TotalEnergies-reported suitable; Meets stated performance (TotalEnergies claim); Confirm in your equipment manual. Where the TotalEnergies product list and data sheet disagree, we show the data sheet’s wording.
RUBIA WORKS 4000 15W-40 SAE 15W-40 · Deutz DQC III-18 LA
OEM-approved (OEM list)
Wording: “DEUTZ DQC III-18 LA” (note: listed under Manufacturer approvals on the TotalEnergies data sheet)
Source: TotalEnergies data sheet, last updated Jul 2026; Also on DEUTZ DQC Approval List, issue 09/2026: DQC III-18 LA, worldwide, remark 'Base Number (TBN) ≥ 9 mg KOH/g'; TotalEnergies product list supplied to Bulk Lubricants Australia, Oct 2026
RUBIA WORKS 5000 10W-40 SAE 10W-40 · Deutz DQC IV-18 LA
OEM-approved (OEM list)
Wording: “DEUTZ DQC IV-18 LA” (note: listed under Manufacturer approvals on the TotalEnergies data sheet)
Source: TotalEnergies data sheet, last updated Jan 2025; Also on DEUTZ DQC Approval List, issue 09/2026: DQC IV-18 LA, worldwide, remark 'Base Number (TBN) ≥ 9 mg KOH/g'; TotalEnergies product list supplied to Bulk Lubricants Australia, Oct 2026
RUBIA WORKS 5000 FE 5W-30 SAE 5W-30 · Deutz DQC IV-18 LA
OEM-approved (OEM list)
Wording: “DEUTZ DQC IV-18 LA” (note: listed under Manufacturer approvals on the TotalEnergies data sheet)
Source: TotalEnergies data sheet, last updated Sep 2023; Also on DEUTZ DQC Approval List, issue 09/2026: DQC IV-18 LA, worldwide, remark 'Base Number (TBN) ≥ 9 mg KOH/g'; TotalEnergies product list supplied to Bulk Lubricants Australia, Oct 2026
What's the difference between Deutz DQC III-18 LA and IV-18 LA?
Deutz describes III-18 LA as 'low-ash high performance diesel and gas engine oils, standard quality, for use in engines with closed crankcase ventilation and/or with high thermal loads'. IV-18 LA is 'low-ash ultra high performance diesel and gas engine oil for engines with the highest levels of output, with closed crankcase ventilation and/or the highest thermal loads'.[2]
| DQC III-18 LA | DQC IV-18 LA | |
|---|---|---|
| Deutz quality level | High performance, standard quality | Ultra high performance |
| Engines | Closed crankcase ventilation and/or high thermal loads | Highest output, closed crankcase ventilation and/or highest thermal loads |
| Rubia Works grades listed | Rubia Works 4000 15W-40 | Rubia Works 5000 10W-40, Rubia Works 5000 FE 5W-30 |
| Region on Deutz's list | Worldwide | Worldwide |
Can I use a DQC IV-18 LA oil where III-18 LA is specified?
Deutz says: 'Engine oils which are released according to higher DQC classes may also be used in the respective lower DQC classes.' So an IV-18 LA oil may be used where III-18 LA is called for, but not the other way round.[2]
Your engine's operating manual still sets the viscosity for your climate and duty, so check it before you switch.(our interpretation)
What does the TBN remark on Deutz's list mean?
Each of these three entries carries the remark 'Basenzahl / Base Number (TBN) ≥ 9 mg KOH/g'.[1]
Deutz's list doesn't explain the remark beside these entries. If your fuel quality or drain interval depends on base number, ask your Deutz dealer how it applies to your engine.(our interpretation)
Are older Deutz DQC releases still valid?
Not the X-10 ones. Deutz's lubricant specification H 0685-3 says releases under the older X-10 classes expired by 31 Dec 2024 at the latest, so check the current list rather than an old data sheet or drum label.[2]
- For MTU engines in the same fleet, see the MTU Category 2.1 vs 3.1 guide.(our interpretation)
Supply
Pack sizes and prices from Bulk Lubricants Australia
For an engine specified to DQC III-18 LA, any of the three grades below fits by class; for IV-18 LA, choose one of the two Rubia Works 5000 grades. Then pick the viscosity your manual gives.(our interpretation) Rubia Works 4000 15W-40 comes in drums; Rubia Works 5000 10W-40 and Rubia Works 5000 FE 5W-30 come in 20 L packs and drums. Each is quoted per order, for collection from Maddington (Perth) or freight Australia-wide. Status details are in the panel above.
RUBIA WORKS 4000 15W-40 SAE 15W-40
- Deutz DQC III-18 LA: OEM-approved (OEM list)
Pack sizes: Drum
Request a price for RUBIA WORKS 4000 15W-40 SAE 15W-40RUBIA WORKS 5000 10W-40 SAE 10W-40
- Deutz DQC IV-18 LA: OEM-approved (OEM list)
Pack sizes: 20L, Drum
Request a price for RUBIA WORKS 5000 10W-40 SAE 10W-40RUBIA WORKS 5000 FE 5W-30 SAE 5W-30
- Deutz DQC IV-18 LA: OEM-approved (OEM list)
Pack sizes: 20L, Drum
Request a price for RUBIA WORKS 5000 FE 5W-30 SAE 5W-30How did we check this?
On 24 Oct 2026 we searched Deutz's DQC Approval List issue 09/2026 (dated 28 Aug 2026) for each Rubia Works grade we stock, and read the class definitions in Deutz's specification H 0685-3 (05/2018). We then compared the results with each grade's TotalEnergies data sheet and the TotalEnergies product list supplied to us.
Found an error or a newer list? Email quotes@bulklubricants.com.au with the source and we’ll review this page.
Where does this information come from?
- DEUTZ AG: DQC Approval List, issue 09/2026 (PDF)
- DEUTZ AG: Lubricant specification H 0685-3, 05/2018 (PDF)
- TotalEnergies data sheet: Rubia Works 4000 15W-40, last updated Jul 2026 (PDF)
- TotalEnergies data sheet: Rubia Works 5000 10W-40, last updated Jan 2025 (PDF)
- TotalEnergies product list supplied to Bulk Lubricants Australia, Oct 2026 (not public)