Hydraulics that hold their film hot and still flow cold
HVLP is the high viscosity index series. It is an HLP with a flatter viscosity–temperature curve — same anti-wear performance, far less change between a winter morning and a summer afternoon. Six grades, ISO VG 15 to 100.
What the viscosity index buys you
Viscosity index measures how much an oil thins as it warms. A higher number means a flatter curve. It is not a quality ranking — on a system that runs at one steady temperature all year it buys nothing. On a system that does not, it is the difference between holding a film and losing one.
The comparison below is between our own grades at the same nominal ISO VG. At 40 °C they are the same oil. At 100 °C they are not.
| ISO VG | Grade | KV 40°C cSt | KV 100°C cSt | VI | Pour °C |
|---|---|---|---|---|---|
| 32 | HLP 32 | 32.00 | 5.350 | 100 | -30 |
| HVLP 32 | 32.00 | 6.200 | 145 | -45 | |
| 46 | HLP 46 | 46.00 | 6.650 | 94 | -24 |
| HVLP 46 | 46.00 | 8.070 | 148 | -42 | |
| 68 | HLP 68 | 68.00 | 8.770 | 100 | -24 |
| HVLP 68 | 68.00 | 11.02 | 153 | -42 |
Read the VG 46 pair: identical at 40 °C, but at 100 °C the HVLP is roughly twenty percent thicker, and its pour point is eighteen degrees lower. One number is the margin between a film and metal contact on a hot afternoon; the other is whether the machine starts on a cold morning.
Cold start is the other half
Pour point across the HVLP range runs from −39 °C on the heaviest grade to −51 °C on VG 15. The mineral HLP equivalents sit between −18 °C and −30 °C.
That matters where a pump has to fill its inlet before the system has warmed up. Too thick on the suction side and the pump cavitates — noise, erosion and damage that happens in the first minutes of the day rather than under load.
Where HVLP belongs
- Deck machinery and cranes exposed to the weather, where ambient swings through the seasons.
- Steering gear and hatch covers on vessels trading between cold and tropical waters.
- Outdoor plant that starts cold and runs hot — the widest temperature range in a working day.
- Systems where the pump maker specifies a viscosity window an HLP cannot hold across the range.
Where a system lives indoors at a controlled temperature, HLP does the same job for less. Specifying HVLP there is not wrong, it is simply paying for a property the system never uses.
Typical properties
Values from the SINOVA Group technical data sheets, Form No. 002-EN, issued 5 January 2025. Typical properties are based on current production; variations may occur.
| Product | KV 100°CcSt | KV 40°CcSt | VI | Flash°C | Pour°C | Densityg/ml |
|---|---|---|---|---|---|---|
| HVLP 15 | 3.810 | 15.00 | 150 | 160 | -51 | 0.865 |
| HVLP 22 | 4.800 | 22.00 | 143 | 180 | -48 | 0.873 |
| HVLP 32 | 6.200 | 32.00 | 145 | 216 | -45 | 0.855 |
| HVLP 46 | 8.070 | 46.00 | 148 | 220 | -42 | 0.865 |
| HVLP 68 | 11.02 | 68.00 | 153 | 226 | -42 | 0.870 |
| HVLP 100 | 14.90 | on request | 155 | 230 | -39 | 0.880 |
The 40 °C viscosity for HVLP 100 is shown on request rather than printed. The data sheet we hold states a figure that is not consistent with an ISO VG 100 grade, and its own viscosity index and 100 °C value point elsewhere. We have asked SINOVA to confirm it rather than publish a number we cannot stand behind — the confirmed value is sent with any enquiry.