How clean is new oil? Not as clean as you think. Contamination often starts before your system ever runs.
Patch test of new hydraulic oil at 10x magnification, clearly showing particulate contamination. Even unused oil can contain damaging debris.
This sample came straight from the oil manufacturer. Under 10x magnification, you can clearly see the particulate contamination. These particles can start causing wear on day one, reducing component life and system reliability.
Here’s why you need to filter new oil before it ever reaches your equipment, with a quick look at the top three ways new oil gets contaminated. We’ll break each one down below.
Why New Oil Isn’t Actually Clean
1. Oil Picks Up Contaminants During ManufacturingOver time, this storage environment introduces solid particles and water vapor, especially as tanks breathe in and out with temperature changes.
3. Transport Adds More Risk
Oil goes through 7-9 changes in custody from the refinery to the end user without filtration along the journey. Whether new oil is transferred via tanker trucks, railcars, or plastic drums, cross-contamination is a common problem. If containers aren’t thoroughly cleaned between uses, remnants from previous fluids can compromise the new oil.
Common Sources of New Oil Contamination
Why Oil Cleanliness Matters
Modern hydraulic and lubrication systems have extremely tight tolerances. Just a few microns of particulate can:
Maintaining the right ISO 4406 cleanliness code is critical to extending equipment life and preventing downtime.
What Is the Recommended ISO 4406 Cleanliness Code for New Oil?
A good upper limit for new oil cleanliness is 16/14/11 (ISO 4406). Typical new oil usually has ISO codes of 19/17/15 or worse, which is far too dirty for sensitive components. This can be a major cause of degradation and premature failure.
How to Meet ISO 4406 Standards: Best Practices for New Oil
1. Filter New Oil on Delivery
Use a dedicated filter cart or kidney-loop system to clean oil as it’s transferred from drum to storage.
2. Use Offline Filtration While Stored
Install water-blocking breathers and high-efficiency particulate breathers and offline filtration systems on your bulk tanks to remove airborne water and fine particulate.
3. Filter Again Before Dispensing
When transferring oil to the machine, use dedicated, closed system dispensing equipment. Minimize use of open funnels or unsealed containers.
Clean Oil = Longer Equipment Life
Filtering new oil may seem like an extra step, but it pays off. Cleaner oil helps:
Don’t wait until your system is already contaminated. Start clean and stay clean.
Frequently Asked Questions (FAQ)
Q: Is new oil clean enough to use right out of the drum?
A: No. Most new oil is not clean enough to meet OEM-recommended ISO 4406 levels. Always filter new oil before use.
Q: What is the ISO 4406 cleanliness code for new hydraulic oil?
A: Typical new oil may have an ISO 4406 code of 19/17/15 or worse. A good upper limit for new oil cleanliness is 16/14/11.
Q: Can oil be filtered while in storage?
A: Yes. Use offline filtration systems to maintain oil cleanliness in storage tanks and prevent water or particulate buildup over time.
Q: What kind of filter should I use to clean new oil?
A: Use high-efficiency β4000-rated filters (typically 3–10 micron) during transfer or with filter carts to reach target ISO 4406 levels.
📥 Next Step: Download Our Free Clean Oil Handling Checklist
Want to make sure you’re doing everything right? Download our Clean Oil Handling Checklist, a quick guide to filtration at every stage from delivery to system fill.
About Donaldson Hy-Pro:
Donaldson Hy-Pro offers a wide range of hydraulic filtration solutions that can help you improve the performance of your machinery. Our filter elements are designed to combat dirt, water, and oxidation by-products, to help keep your systems running at peak performance.
If you're looking for a way to reduce filter expenses, improve oil cleanliness, and extend the life of your equipment, Donaldson Hy-Pro can help. Contact us today to learn more.