Which Hydraulic Oil Do I Need? The Complete Guide to the KOMPO® Range at HTS Spares
By Travis Knappett, KOMPO® Oil & Grease Specialist at HTS Spares
Hydraulic oil is not just a consumable, it is a critical component of every hydraulic system. The right oil keeps pumps, valves, cylinders and seals working correctly. The wrong one accelerates wear, damages seals, and can turn a routine service into an expensive repair.
At HTS Spares, we supply the KOMPO® range of premium hydraulic oils alongside our full range of hydraulic couplings, hoses and accessories. This guide is designed to help operators and maintenance teams choose the right grade, first time.
What does the ISO VG number mean?
The number in every hydraulic oil grade (32, 46, 68) refers to its ISO Viscosity Grade (ISO VG), measured in Centistokes (cSt) at 40°C. As my recent hydraulic guide explains, the higher the number, the thicker the oil and the greater its resistance to flow.
In simple terms:
- ISO VG 32: thinner, better for cold conditions and high-speed equipment
- ISO VG 46: the most common all-round grade for general plant and industrial use
- ISO VG 68: thicker, for high-temperature, high-load or heavy-duty systems
Some grades may cross over, so always check your manufacturer specification before ordering.
The KOMPO® hydraulic oil range
HTS Spares stocks the KOMPO® range across multiple grades and pack sizes - 5 litre, 25 litre and 205 litre barrel options. Every grade is formulated with anti-wear additives, corrosion inhibitors, anti-foam properties and rapid air release.
🛢️ KOMPO® HM32 - ISO VG 32
HTS codes: HLU0894 (5L) | HLU1011 (25L) | HLU1012 (205L)
A lower-viscosity oil that flows easily in cold conditions - the right choice for mobile plant operating in colder UK temperatures and hydraulic breaker circuits where rapid pressure cycling demands fast hydraulic response.
🛢️ KOMPO® HLP46 - ISO VG 46
HTS codes: HLU0890 (5L) | HLU1017 (25L) | HLU1018 (205L)
The most widely used hydraulic oil grade in UK plant and construction. HLP 46 complies with DIN 51524 Part 2 which is one of the most recognised international standards for hydraulic lubricants. It also carries a full anti-wear, corrosion inhibitor and extreme pressure additive package. This is the default choice for excavators, dumpers, rollers and general construction plant in moderate UK temperatures. As Completely Hydraulic confirm, ISO 46 is the standard for general hydraulic systems and most plant machinery.
🛢️ KOMPO® HM68 - ISO VG 68
HTS code: HLU0016 (25L)
A heavier viscosity oil for high-load, high-temperature applications. ISO VG 68 is designed for systems requiring large load-carrying ability. This would be the correct choice for heavy industrial plant running continuous duty cycles at elevated temperatures, or older machines with larger internal clearances.
🛢️ KOMPO® HVI 46 - High Viscosity Index
HTS codes: HLU1025 (20L) | HLU1026 (205L)
HVI oils are formulated to stay closer to their rated viscosity across a wider temperature range. A high VI oil provides stable performance from cold UK morning starts through to full operating temperature, removing the seasonal grade-selection guesswork for mixed plant hire fleets running year-round.
🛢️ Magnol HVI46 Hi-Temp
HTS code: HLU0018 (25L)
Formulated for the most extreme temperature conditions, from -20°C in cold storage environments to elevated temperatures in industrial hydraulic systems. Where standard HVI 46 is not enough, Magnol covers the full extreme range.
🛢️ Terralus BVG46 - Biodegradable
HTS code: HLU0013 (25L)
A readily biodegradable, mineral-oil-free hydraulic fluid which is zinc-free and contains no heavy metals. The correct specification for sites near watercourses, on green infrastructure projects, in forestry, or on any site with environmental compliance requirements. Compatible with the Manuli FF flat-face coupling series, which is itself designed to minimise fluid spillage on eco-sensitive sites.
Grade comparison table
| Grade | ISO VG | HTS Code(s) | Best for |
| HM32 | 32 | HLU0894, HLU1011-HLU1014 | Mobile plant in cold UK conditions, breaker circuits, high-speed systems |
| HLP46 | 46 | HLU0890, HLU1017, HLU1018 | General plant, excavators, dumpers, agricultural equipment |
| HM68 | 68 | HLU0016 | Heavy industrial plant, high-temperature continuous duty |
| HVI 46 | 46 HVI | HLU1025-HLU1026 | Mixed fleets, year-round operation, variable temperatures |
| Magnol HVI46 Hi-Temp | 46 HVI | HLU0018 | Cold stores, extreme temperature industrial systems |
| Terralus BVG46 | 46 | HLU0013 | Eco-sensitive sites, forestry, near watercourses |
Always check your machine's manufacturer specification before selecting an oil grade. If you are unsure, call the HTS Spares technical team on 01432 373350 before ordering.
Common questions
Can I mix hydraulic oil grades? No. Mixing grades changes the effective viscosity and can reduce the performance of the additive packages in both oils. Drain and refill with the correct grade before operating.
Can I use ATF as hydraulic oil? Only where the manufacturer explicitly approves it. As my recent blog explains, ATF contains additives not suitable for most high-pressure hydraulic systems and can damage pumps, valves and rams.
Does hydraulic oil go off? Yes. Most manufacturers recommend annual oil changes or changes at a defined service hour interval. A quality oil with strong oxidation stability (like KOMPO® HLP46) will resist breakdown and extend service intervals.
Order KOMPO® oils at HTS Spares
Next-day delivery is available on orders placed before 4pm, Monday to Friday
View the full KOMPO® oil and lubricants range →
View hydraulic couplings and hoses →
For technical advice: call our office on 01432 373350, or email me - travis.knappett@htsspares.com
