oil cleanliness inconsisency

Check with the customer for any large amounts of top up oil, this can affect the readings.

Another more question please...

For a Particale count test:

should I use the same sample for ICP test which is taken before the filter.

or should I take another sample after the filter just for Particle count test.

Assuming that if we use the same sample of ICP test we will have a higher level of contamination than the real oil in the bearings, because the oil in the bearings is filtrated.

regards

Noureddine.T

Dear Motorist,

the sample before will take more wild excersions as conditions change, but may provide better data.

Please have someone look into sensativity for you. The lab should be able to do this. I mention this because I know normal spectroscopy can not see any particles > 10 um in size. Find out what the upper and lower lmits of detection are.

Good Luck.

Motorist,

For ISO cleanliness, I've found the Filterpatch test most reliable in terms of consistency of results within a lab and comparing different labs. The most variation I've come across is by one ISO code as part of a round robin trial.
The sample is essentially washed and filtered through a filter paper. The solvent used is hexane or heptane (filtered solvent). The filter patch is compared to a comparator such as a PALL comparator and the ISO code is then determined.
Speak to the labs to see which one can offer this method. The lab will probably have a method that is somewhat a modified version to the PALL method. The lab should also be able to provide a digital photo of the patch as part of routine analysis report.
The advantage of filterpatch method is that it does eliminate some of the interference issues experienced with automatic lazer particle counters as previously mentioned. It will also give you a visual representation of why the ISO code has gone up. It may also show up any abnormal wear material. Also as the turbine oil ages, you will also notice a change in colour on the patch test as well.
As mentioned before, look at the ISO cleanliness results in conjunction with other results such as ICP wear metals, PQI, water content etc. For turbine oils it's also important to include TAN and RPVOT results as well.
Typically, a sample before the filter is taken. You can take samples post filter as well which may give you some indication of filter efficiency. However, I've come across cases where pre filter and post filter results are almost identical.

Sampling methods, sampling practices, personnel, bottle cleanliness, the list goes on. There are some many variables to collecting a representative and accurate sample.
I would look at how you sample and the procedures involved, particuarly if more than one person is collecting the samples.