“Can I use this one fluid for several lubrication needs?” We get this question fairly often, most commonly when a customer is already using one hydraulic fluid and has a piece of equipment that calls for a different fluid type or spec. The question makes sense to ask as customers are always looking for ways to consolidate their fluids (and hopefully save money in the process).
The main rule of thumb when it comes to using a fluid in equipment for which it’s not specifically intended is this: if the fluid you want to use for the other piece(s) of equipment is a grade up from what’s called for, you’re probably safe. The reason is that the upgrade in viscosity usually translates to safer protection of the equipment rather than stepping down in viscosity. However, use caution and always check with a fluid supplier before consolidating your fluid supply.
Here are some common scenarios that might help you determine if one fluid will work for multiple applications:
- Hydraulic oils. If you run tractors or construction equipment, you probably have tractor fluid that also serves as transmission/brake fluid. Can you use that fluid in a skid steer that calls for ISO-46 hydraulic fluid? If there are no extremes in the environmental temperatures or system temperatures (i.e. very hot or very cold) you probably can, but you should watch for sluggish movement as temperatures dip. If that happens, you might need to change fluids. In addition to operating temperatures, you should also consider the weight/force of the loads on the hydraulics and how the hydraulics are performing.
- Gear oils. If you use a gear oil with a specification of AGMA EP-4 and have another gearbox that calls for EP-5, we’d first ask how heavily loaded the gearbox is and what kind of operations you’re doing with it (i.e. what the gearboxes are turning). If the load is significant and the system is experiencing significant demands, always defer to the fluid with thicker viscosity to ensure proper performance. If a lower viscosity fluid is used, this could cause catastrophic failure or vastly accelerated wear. In contrast, if the fluid is “too” thick, a primary consequence is potential energy inefficiency, a comparatively less problematic situation.
- Engine oils. If you have a mixed fleet of gas and diesel engines, you might wonder if you can use the same engine oil in both. In this case it’s generally acceptable to use the diesel oil on a gas engine if it’s the right viscosity grade…but never vice versa!
Is Thicker Always Better?
While we recommend erring on the conservative side in determining if a single fluid could work in multiple applications, in some situations you do need a very specific fluid, and using one not intended for the application could be hazardous. If your equipment has very specific operational needs, like a system with tight clearances, such as servo valves, the fluid viscosity can affect manufacturing tolerances. For example, if the machine has precise movement of the spindle or part and you use a fluid that is too thick, the machine/tool might not move appropriately and cause tolerance or stacked tolerance issues with the part.
As you can see, while it’s sometimes possible that a single fluid can satisfy a combination of your fluid needs, the best approach is to consult with a lubricant specialist or have a lubrication audit done to ensure safety and machine/engine compatibility. Your fluid supplier should be able to gauge whether you can consolidate fluids based on your equipment’s operating environment and any issues you’re currently experiencing.
Our team of fluids experts would be happy to walk through your facility to help you determine the most effective – and cost-effective – ways to keep your equipment in top shape! If you have questions on fluid consolidation or choosing the right lubricants for your equipment, contact Tony Springer at TSpringer@uslube.com or by phone at (800) 490-4900 ext. 8823.