Tractor or excavator: Cummins, CAT, Deutz, JASO DH — which oil?

It is a familiar picture to anyone who runs a farm or a small fleet of machinery: a tractor, a combine, a loader, a couple of excavators, each with its own engine. The drum of diesel oil carries a dozen or so codes in small print: Cummins CES 20086, CAT ECF-3, Mack EO-O Premium Plus, Deutz DQC IV-18 LA, MTU 3.1, JASO DH-2. The salesman waves a hand: “It’s all 15W-40 for diesels, pour it into everything, engine and hydraulics alike.” In fact every one of these codes is a separate requirement, and by no means all of them can stand in for one another.

The idea of one oil for a whole mixed fleet has already come up in the article on oils for a mixed fleet of cars; since then finding such an oil has become harder, and these codes are one of the reasons. The approvals of the European truck makes (Mack EOS-4.5 among them, since Mack belongs to the Volvo group) are covered in the article on oil for trucks and buses. Here we deal with the engines most often found in farm and construction machinery.

Why you look for the code in the manual and on the engine, not on the bonnet

Machinery lives by engine hours, not kilometres: heavy loads, dust, long idling, fuel from all sorts of drums. And the maker of the tractor or excavator quite often fits an engine from another company. The machine’s manual then gives either the engine maker’s code or the machine maker’s own (at CNH, for example, the MAT codes for engine oils). So the first thing to know is who made the engine and what the machine’s manual asks for. Looking up the oil requirement by the badge on the bonnet is a bit like choosing batteries by the colour of the remote control.

In short, an engine maker’s code is, as a rule, an API or ACEA class to which the engine maker has added its own tests or its own limits. That is why “API CJ-4” on a can does not always mean “Cummins CES 20081”, even though both rest on the same class.

American engines: Cummins, CAT, Detroit, Mack

American makers build their requirements on the API diesel classes, so they are easy to read as a ladder:

1. The code demands more than the class. CES 20076 is CH-4 plus a 300-hour test on a Cummins M11 engine. There is also CES 20077 on a European base: ACEA class E5 plus another 300-hour test (E5 itself has long been withdrawn). CAT ECF-2 is the full CI-4 programme plus a 500-hour test on the C13 engine and sulphated ash of no more than 1.5%. ECF-3, on the other hand, is simply the full API CJ-4 programme with nothing cut (the C13 test is in it anyway).

2. The new code covers the old one. Cummins recommends CES 20086 wherever it used to recommend 20081. There is no separate CAT code for CK-4 in our catalogue: CK-4 oils mostly carry ECF-3 (of the 44 oils with ECF-3, 41 are CK-4). And API has already approved the next classes, CL-4 and FB-4, with oils licensed to them from 2027.

3. FA-4 is a branch of its own. These oils have a lower high-temperature high-shear viscosity (HTHS) and are not backward compatible; API wrote the category for some on-road engines from model year 2017 onwards. Detroit keeps its 93K223 list only for engines certified to the American EPA 2010 standards and later. In the engine of a tractor or an excavator, FA-4 goes in only if the manual expressly allows it.

And who stands behind the code? In the ECF-3 specification itself, Caterpillar states that it does not verify oil makers’ claims of compliance with it, so an ECF on the can is, as a rule, the oil maker’s own word. Detroit, by contrast, publishes lists of approved oils for each DFS number on its website. How to tell an approval from “meets the requirements” is explained in the article on how to check an oil approval.

And if an old tractor’s manual simply says API CF or CD, the article on API class CF explains what to do. CI-4, as before, suits diesels without a particulate filter (see API class CI-4).

Deutz and MTU: their own classes, their own lists

Deutz has run its own DQC quality classes since 2007. Under each class lies an ACEA or API class, and classes III and IV add Deutz’s own requirements on top:

• DQC I-02 is the minimum level: ACEA E2 or API CF/CF-4;
• DQC II-18 is ACEA E4/E7 or API CI-4;
• DQC III-18 is E4/E7 plus Deutz requirements;
• DQC IV-18 is E4 plus Deutz requirements, with the longest change interval;
• DQC II-18 LA, III-18 LA, IV-18 LA are the low-ash (LA) versions of the same levels for engines with exhaust aftertreatment; underneath are E6, E9, CJ-4 or CK-4. IV-18 LA also suits TTCD engines.

The figures after the hyphen are the generation of the requirements. The -10 series was replaced by the -18 series (among the reasons given are the European Stage V limits, in force since 2019), and approvals to -10 remained valid until 31 December 2024 at the latest. An oil of a higher DQC class can be used where a lower one is required, but only within its own branch: if the manual calls for an LA class, you need a low-ash LA oil. Deutz publishes its approved oils in a separate list on its website.

At MTU the categories are 1, 2, 2.1, 3 and 3.1: the higher the figure, the higher the requirements, and “.1” marks a low-ash oil. MTU lists its approved oils in its specifications. For generator engines of the 2000 and 4000 series without a centrifugal filter it gives, as a guide, 250, 500 and 750 engine hours between changes for categories 1, 2 and 3, and those figures should be confirmed by oil analysis.

Japanese machinery: JASO DH-1 and DH-2

The Japanese classification of diesel oils, JASO M355, belongs to the Society of Automotive Engineers of Japan. DH-1 appeared in 2000 for engines without a particulate filter, DH-2 in 2005, this time with reduced ash for engines with a filter. If the manual of a Japanese machine says JASO DH-1 or DH-2, look for exactly that mark. On the oils in our catalogue DH-2 mostly sits alongside ACEA E11, E9 or E7.

High-sulphur fuel, TBN and Stage V

The sulphur in fuel burns and turns into acids, which end up in the oil. Alkaline additives neutralise them, and the oil’s total base number, TBN, shows how much of that reserve is left. The more sulphur in the fuel, the faster the reserve is used up.

MTU says it outright: if the fuel contains more than 0.5% sulphur, you need an oil with a TBN above 8 mg KOH/g and shorter intervals, and the low-ash oils of categories 2.1 and 3.1 are approved only for fuel with no more than 50 mg of sulphur per kilogram. In its 2017 recommendations Cummins advises against using CES 20081, 20086 and 20087 oils in engines without exhaust aftertreatment if the fuel contains more than 15 ppm sulphur: their initial TBN is, as a rule, lower, and the recommendation here is CES 20078. So the “newer” code is not always the better one: a CK-4 oil in an old engine on high-sulphur fuel is no upgrade.

But there is a flip side too. A modern Stage V or Tier 4 engine with a particulate filter, run on an ashier oil meant for engines without a filter (CI-4, say), will gradually choke the filter with ash (more on this in the article on a diesel with a particulate filter).

One drum for the whole fleet?

Cummins, CAT and Deutz codes often appear together on one drum. But you will have to check each machine: the required code and the viscosity must be on the label for EVERY engine. An engine without a filter on dubious fuel and a Stage V engine with a filter, as a rule, cannot run on the same oil.

Gearbox, hydraulics, wet brakes: a separate story

In a tractor the gearbox, the hydraulics and the wet multi-plate brakes often run on one oil. Lubrication is not all that matters here; so does friction: the clutch and brake plates must grip without slipping and without judder. The detergent additives and friction modifiers of an engine oil are designed for something quite different.

So these units have codes of their own: Caterpillar TO-4 for powershift gearboxes, final drives and wet brakes; John Deere JDM J20C, CNH MAT 3525, Massey Ferguson MF 1135 and MF 1141, Ford/New Holland M2C134D for universal tractor oils. Caterpillar itself warns that its GL-5 gear oil does not meet the TO-4 requirements and is not suitable where TO-4 is required. If the machine’s maker allows an engine oil in the hydraulics, it says so, with the class and viscosity. If it does not say so, do not experiment.

What the owner of machinery should do

1. The engine plate and the manual. Who made the engine, and which code the manual asks for: CES, ECF, DQC, an MTU category, JASO DH or the machine maker’s own code.

2. The code and viscosity on the label. And note how it is worded: “approved” or “meets”.

3. The fuel. An engine with a particulate filter needs ultra-low-sulphur fuel. For an old engine on dubious fuel, look for what the manual advises specifically for high-sulphur fuel, shorten the interval and send the oil for analysis from time to time.

4. The gearbox and hydraulics go by their own code, not by “whatever was left in the drum”.

I will say it again: with machinery, as with a passenger car, what decides is the requirement in the manual — the engine maker’s or the machine’s own — and not the words “for diesels” or the salesman’s advice. And repairing an excavator engine costs far more than the dearest drum of oil.