When exposed to cold temperatures, problems can culminate quickly within a hydraulic system, often starting with an increase in oil viscosity and cavitation.
With the possibility of these issues leading to damaged or inefficient machinery or even system failure, it’s not surprising that many are curious about how cold weather affects fluids used in hydraulic equipment.
Before addressing the most frequently asked questions related to cold weather care, it’s important to note that winterizing hydraulic equipment can help prevent:
- Damaging increases in viscosity
- Trapped moisture in piping
- Ice build-up
- Cavitation and lack of lubrication
- Loss of hydraulic pump and motor function
- Damaged hydraulic hoses, seals, mountings, fittings, and other rubber components
Cold weather doesn’t have to damage hydraulic parts and systems, and finding answers is a good way to ensure that it doesn’t.
Q: Does Hydraulic Fluid Freeze?
A: The Short answer is yes.
The long answer is that when it reaches the freezing point (-10° F), yes hydraulic fluid will freeze, but first, the viscosity will increase and slow machinery or cause damage.
High oil viscosity can lead to starved pumps,?cavitation, and lack of lubrication, and close attention should be placed on grade, pour point (and added depressants), as well as the viscosity index (VI) of fluids in cold weather.
Q: What is the Best Hydraulic Fluid in Cold Weather?
A: Although a hydraulic oil with a low viscosity index will alter the viscosity more than those high on the VI, it may be more relevant for cold weather changes.
Using an?ISO 32 or 22 is a good bet for winter, compared with a standard ISO 46 hydraulic oil used in warmer weather.
The higher the VG number of an ISO VG Grade (where ISO is the?International Standards Organization), the more viscous the fluid will be. The VG number tells you which hydraulic oil is thicker. This is sometimes referred to as the hydraulic oil weight (W). See the chart below for other viscosity equivalents.
How Do I Keep Hydraulic Fluid From Freezing?
A: Cold temperatures can alter the functionality of hydraulic oil even before it freezes, and can damage equipment.
To avoid damage due to increased viscosity and freezing, you can heat fluid at?low voltage?(typically 12 or 24 V) with either:
- A screw plug heater that fits the size and wattage of application
- A silicone rubber blanket heater, which can be placed on the outside of fluid tanks
Some other tips to keep fluid flowing in cold weather (winterizing) and avoid freezing:
- Check the oil. Before starting, make sure that the fluid in the hydraulic system is flowing.
- Give your hydraulic equipment and fluid time to warm up. Oil needs to be warm to the touch to indicate adequate heat in the hydraulic system.
- Inspect for wear and tear. Inspect components for cracks and tears and have spare seals, rubber mounts, hoses, and fittings on hand to minimize downtime in the cold.
What is the Freezing Point of Hydraulic Fluid?
A: The freezing point that causes hydraulic oil to gel and become unusable is -10 degrees Fahrenheit.
However, the ambient freezing point is 32 degrees Fahrenheit, in which fluid can still increase in viscosity before gelling, causing performance issues with hydraulic pumps and motors.
How Do I Winterize my Hydraulic Pumps, Motors, and Valves?
To summarize, winterizing hydraulic parts involves focusing on winterizing fluids, considering viscosity considerations and consistent checks on those fluids, and preparing equipment before use.
Finally, winterizing involves storing fluids, equipment, and components properly.
Hydraulic Parts Source is a leading fluid power remanufacturer, and we’re ready to serve you. Contact us today to experience OE quality for a fraction of the time and cost by calling (888) 477-7278 or get a quote by emailing sales@hydparts.com.