Oil sampling instructions
You can read the oil sampling instructions directly on this page or download them as a PDF for later use.
When sending your oil sample to us, please remember to include a completed sample information form. You can download the blank form using the button below.
Send the completed form and sample to:
Fluidlab Oy, Iso-Heikkiläntie 8 (Room 229, 2nd floor), 20200 TURKU, Finland
Basics of oil sampling
Sampling is the most important step in oil analysis.
The goal is to transfer as representative an oil sample as possible from the system into the sample bottle.
To achieve this, keep the following key points in mind:
- Take the sample from a running, warm system — ideally from a point where the oil is flowing turbulently
- The person taking the sample should be motivated and properly trained
- Always use clean tools and ensure the sampling area is clean
- Thoroughly flush the sampling point with oil before collecting the sample
- Handle the bottle with care. Do not fill it right to the top — leave a bit of space
- For consistency and accurate comparisons over time (trend), always sample from the same spot using the same method
- Aim to send the sample to the lab as soon as possible — preferably within 1 to 2 weeks
Avoid sampling from the drain valve, filter bowl, or dipping into the tank unless absolutely necessary.
Sampling from various points in the system over time can help pinpoint which parts contribute most to contamination.
Important: Be extra careful when working with high-pressure lines!
Sampling tools
To ensure reliable results, use proper sampling tools. If you use your own bottles, wash them thoroughly and rinse them once or twice with the same oil before taking the actual sample.
Be aware that unused plastic bottles may contain more particles than even dirty oil. Likewise, unfiltered tap water is not particle-free. While pharmacy glass bottles may be sterile (microbe-free), they are not necessarily free of particles either.
How to take the sample
Follow these best practices when taking your oil sample:
- If possible, take the sample while the system is running and the oil is at operating temperature
- If the system must be shut down, take the sample within 15 minutes of shutdown
- Use clean equipment and transfer the warm oil into a particle-free bottle
- A typical analysis requires 150–250 ml of oil. For special tests, more may be needed — check with us if unsure
- You can sample from pressure lines using a minimess hose, from tanks using a vacuum pump, or from return lines directly into the bottle
- Never sample from the bottom drain valve — it’s where contaminants settle
- Avoid “dipping” into tanks, as bottles can fall in
- For accurate trend tracking, always take the sample the same way, from the same location
Method 1 – Sampling from a valve
Use this method if your system has a dedicated sampling valve.
Note that the oil pressure should be below 14 bar and the flow should be steady.
What you need:
- A connector that fits the valve
- A clean, particle-free sample bottle (do not place the cap face-down or in your pocket)
- Clean solvent (filtered to 0.5 μm absolute) for rinsing the hose and sampling area — if no solvent, flush thoroughly with oil
Steps
- Open the valve and flush at least 500 ml of oil through it — leave the valve open
- Hold the sample bottle under the valve and collect at least 200 ml of oil
- Rinse the inside of the bottle with oil, then empty it — repeat this twice
- Fill the bottle about 5/6 full with the actual sample, then close the cap
- Close the sampling valve
- Label the bottle clearly with sample details
Warnings!
– Oil from >10 bar pressure lines can penetrate skin and cause blood poisoning — always wear safety glasses, gloves, and overalls
– Used oil is hazardous to the environment — protect the area with rags or absorbent materials
– Run the system for at least 30 minutes before sampling to ensure even particle distribution
– Keep the bottle as particle-free as possible. Handle the cap with the opening facing down
– Do not touch the valve during sampling — it may release unwanted particles into your sample
– Rinse tools before each use or flush 300–500 ml of oil through them first
Method 2 – Sampling from a tank or drum
Use this method when sampling from stationary tanks or oil drums.
What you need:
- A vacuum pump
- Flexible plastic tubing
- A clean sample bottle (do not place the cap face-down or in your pocket)
- Clean solvent (filtered to 0.5 μm absolute) — or flush with oil using the instructions below
Steps
- Use the pump to pull 200 ml of solvent through the hose into Bottle A, then empty it
- Insert the hose into the tank, aiming for the mid-layer of oil
- Pump 200 ml of oil into Bottle A, empty it, and set it aside
- Connect Bottle B to the vacuum pump and draw in another 200 ml of oil
- Rinse Bottle B, empty it, and repeat
- Pump 250 ml of oil into Bottle B and seal it
- Label Bottle B with the sample details
Warnings!
– Lubricants can carry harmful contaminants — always wear gloves and safety glasses
– Always use rags or absorbent material to protect the surrounding environment
Marking background info
Fill the bottle to no more than 5/6 full. This leaves room for mixing at the lab, ensuring even distribution of impurities during analysis.
Label the bottle with equipment information and sampling date.
Fill out the sample information form with the following information:
- Equipment ID and/or name
- Exact oil brand and type
- Oil temperature and hours of use
- Any oil top-ups or changes
- Filter type and filtration grade
- Any known issues or additional notes
- Sampling date and name of the person who took the sample
Send the sample with the completed form to:
Fluidlab Oy, Iso-Heikkiläntie 8 (Room 229, 2nd floor), 20200 TURKU, Finland