Technical Specifications
| Property | Unit | Typical Value | Test Method |
|---|---|---|---|
| Appearance | Brownish-red viscous liquid | ||
| Density at 20°C | kg/m³ | 998 | ASTM D4052 |
| Viscosity at 100°C | mm²/s | 110 | ASTM D445 |
| Flash point | °C | 190 | ASTM D93 |
| TBN | mgKOH/g | 95 | ASTM D2896 |
| Calcium | % | 4.1 | ASTM D4951 |
| Zinc | % | 1.05 | ASTM D4951 |
| Phosphorus | % | 1.40 | ASTM D4951 |
| Nitrogen | % | 6.2 | ASTM D3228 |
| Molybdenum | % | 0.07 | ASTM D4951 |
* Typical values from batch production. Batch-specific COA available on request.
Technical content reviewed by the CheMost additives team · Specifications last reviewed
Application Data
Recommended Treat Rate
6.0–10.0 wt% depending on target API level (CF-4/CH-4/CI-4)
What Is the API CH-4/CI-4 Diesel Engine Oil Additive Package (PA3055H)?
CheMost PA3055H is a heavy-duty diesel engine oil additive package built for API CH-4 and CI-4 — a single concentrate carrying the detergent, dispersant, antiwear and antioxidant functions a diesel crankcase oil needs. It is a brownish-red viscous liquid with a Total Base Number (TBN) of 95 mgKOH/g, 1.05% zinc, 6.2% nitrogen and 0.07% molybdenum.
PA3055H controls deposit formation and keeps the engine interior clean, with anti-wear performance that reduces wear and extends engine lifespan, and antioxidant performance that supports a longer oil change interval. It is published against three diesel service levels — CF-4, CH-4 and CI-4 — each at its own treat rate.
PA3055H is supplied as a concentrate. The blender adds a viscosity index improver plus any remaining functional additives separately (see Formulating With PA3055H below); matching suitability varies with the base oil used.
How PA3055H Protects a Heavy-Duty Diesel Engine
Acid neutralisation
A TBN of 95 mgKOH/g (ASTM D2896) is the alkaline reserve that neutralises the sulfuric and nitric acids formed by diesel combustion. Because the published treat rate differs by target level, so does the TBN this package contributes — see the treat-rate table below.
Heavy soot dispersancy
6.2% nitrogen (ASTM D3228) is a notably high figure, consistent with a nitrogen-rich ashless dispersant loading — the kind of chemistry heavy-duty diesel formulations lean on to keep the higher soot load of compression-ignition combustion suspended rather than thickening the oil.
Antiwear protection
1.05% zinc and 1.40% phosphorus (both ASTM D4951) are consistent with zinc dialkyldithiophosphate (ZDDP)-type antiwear chemistry, which is commonly associated with sacrificial tribofilm formation on loaded surfaces — the anti-wear performance behind PA3055H’s reduced-wear, extended-lifespan positioning.
Antioxidant contribution
PA3055H’s antioxidant performance supports a longer oil change interval; its 0.07% molybdenum (ASTM D4951) is consistent with a supplementary friction-reducing role alongside the antiwear chemistry above.
API CF-4, CH-4 and CI-4 — Coverage and Current Status
PA3055H is published against three diesel service levels, and their current/obsolete status is not uniform — we state it plainly rather than blur it into one line. Checked against API’s own oil-categories page (2026-08-26):
CH-4 — Current
Introduced in 1998 for high-speed four-stroke engines meeting 1998 exhaust emission standards, compounded for diesel fuel up to 0.5% sulfur. API lists CH-4 as Current and notes it can be used in place of CD, CE, CF-4 and CG-4 oils.
CI-4 — Current
Introduced in 2002, formulated to sustain engine durability where exhaust gas recirculation (EGR) is used. API lists CI-4 as Current and notes it can be used in place of CD, CE, CF-4, CG-4 and CH-4 oils; some CI-4 oils may also qualify for the CI-4 PLUS designation.
CF-4 — Obsolete
API now lists CF-4 as Obsolete, with the caution that it is not suitable for most diesel-powered automotive engines built after 2009. PA3055H’s CF-4 treat-rate figure is published for reference and for servicing older equipment still calling for it; new-build formulations should target CH-4 or CI-4 instead.
Service-category performance is a property of the fully formulated finished oil, not of an additive package on its own. PA3055H is used in formulations targeting API CH-4, CI-4 or CF-4; final qualification depends on your base oil, viscosity modifier and complete additive slate.
PA3055H Applications in Heavy-Duty Diesel Engine Oil
Current-fleet heavy-duty diesel oils
On-highway and off-highway diesel oils targeting API CH-4 or CI-4, including EGR-equipped engines that CI-4 was specifically formulated to sustain.
Legacy-fleet servicing
The CF-4 treat-rate figure supports formulations servicing older diesel equipment that still specifies it, with the honest caveat that CF-4 is an Obsolete API category.
Extended-drain formulations
The antioxidant performance behind PA3055H’s longer oil change interval claim supports extended-drain diesel oil programs.
Wide viscosity coverage
Blend with a viscosity index improver to reach the required SAE grade.
PA3055H Treat Rate by API Service Level
PA3055H is published at a different treat rate for each target service level:
| Target API level | Treat rate | TBN contributed* | Zn contributed* | N contributed* |
|---|---|---|---|---|
| CF-4 (Obsolete) | 6.0% | 5.7 mgKOH/g | 630 ppm | 3,720 ppm |
| CH-4 | 8.0% | 7.6 mgKOH/g | 840 ppm | 4,960 ppm |
| CI-4 | 10.0% | 9.5 mgKOH/g | 1,050 ppm | 6,200 ppm |
Treat rate rises with service-category demand: 6.0% for the older CF-4 target, 8.0% for CH-4 and 10.0% for CI-4 — the newer, EGR-durable category needs the most package. No other target levels are published for this grade, so none are shown here.
Treat rate is a starting point tied to your base oil and the rest of your additive slate. Matching suitability varies with the base oil used — confirm your formulation with our technical team before production blending.
Formulating With PA3055H — What You Still Need to Add
PA3055H is an additive package, not a fully formulated additive system. Additional functional additives — defoamer additives, pour point depressants, thickening agents or viscosity index improvers — need to be added during use. The exact selection depends on the base oil and target grade:
Viscosity index improver
Needed to reach the target SAE grade. See EPM or liquid OCP — the choice affects shear stability and the final VI.
Defoamer
Where foam control is needed, see PDMS silicone defoamer or our silicone-free option for systems sensitive to silicone carry-over.
Pour point depressant
Whether one is needed depends on the base oil and low-temperature target. See polymethacrylate (PMA) pour point depressant.
Thickener, where specified
Whether one is used depends on the viscosity grade being built.
Browse the full range on the diesel engine oil additive packages hub, or the individual additive components catalogue.
Documentation, Qualification & Regulatory Support
Regulatory documentation
REACH, TSCA and country-specific market registration documentation support available on request.
Third-party inspection
SGS / Intertek / BV pre-shipment inspection can be arranged on request.
Custom grades & packaging
Custom package variants and packaging formats can be discussed with our technical team.
Formulation support
Treat-rate calculation and base-oil compatibility guidance — matching suitability varies with the base oil used, so confirm with our team.
COA, SDS and certificate of origin are provided with every shipment. Request full documentation or a sample — enquiries are answered within 12 hours.
Packaging, Supply and Lead Time
Packaging
200 kg metal drum · 1000 kg IBC tank.
Storage
Dry, clean, well-ventilated warehouse. Maximum storage temperature 50°C; maximum blending temperature 70°C. Shelf life 36 months at ambient temperature.
Minimum order
One drum or one IBC — no minimum order value.
Incoterms & ports
FOB · CIF · EXW from all major Chinese ports.
Stocked and shipped worldwide, typical lead time 1–15 days; 36-month shelf life; samples and quotations answered within 12 hours.
Frequently Asked Questions
What is the difference between CH-4 and CI-4 engine oil?
CH-4, introduced in 1998, was compounded for diesel fuel up to 0.5% sulfur and controls shear-related viscosity loss, sludge and volatility. CI-4, introduced in 2002, builds on CH-4 to sustain engine durability specifically where exhaust gas recirculation (EGR) is used, and can be used in place of CH-4 oils. Both are current API categories; PA3055H is published against both, each at its own treat rate.
What is CF-4 in engine oil, and is it still current?
CF-4 was an earlier diesel category for high-speed four-stroke engines with lower emissions requirements than CH-4 or CI-4. API now lists CF-4 as Obsolete, cautioning it is not suitable for most diesel-powered automotive engines built after 2009. PA3055H publishes a CF-4 treat rate for servicing older equipment that still calls for it; new-build formulations should target CH-4 or CI-4.
How much PA3055H is needed, and does it differ by target level?
Yes — 6.0% of the finished oil for CF-4, 8.0% for CH-4 and 10.0% for CI-4. Treat rate rises with service-category demand: the EGR-durable CI-4 target needs the most package. Final treat rate should be confirmed against your specific base oil and additive slate.
What is the best additive package for a diesel engine oil?
It depends on the target API service level and fleet. PA3055H is built for CH-4 and CI-4, the current heavy-duty diesel categories, with a CF-4 figure available for legacy servicing. The right choice balances TBN, nitrogen (dispersancy) and antiwear chemistry against the soot load and EGR duty of the target engine — confirm the fit with our technical team.
What else has to be added besides PA3055H?
Additional functional additives — defoamer additives, pour point depressants, thickening agents or viscosity index improvers — need to be added during use. Which ones you need depends on your base oil and target grade. PA3055H is an additive package, not a fully formulated additive system.