I am using Mann PU 825X fuel filters on my car. I was asking myself what micron rating these filters are working.
Information isn't online so i asked Mann directly. Here is the answer that i got, maybe handy for other tdi owners:
Good Afternoon Mr, thank you for your enquiry.
We do not publish the micron rating on the website, as the term ‘micron rating’ is often misunderstood, as you cannot label a filter purely a ‘5 micron’ filter as this means nothing without the efficiency rating (in percentage).
For example, a filter could be 5 micron at 25% efficiency (i.e. retains 25% of all 5 micron particles) or 5 micron at 95% efficiency (retains 95% of all 5 micron particles).
Both filters are hence ‘5 micron’, but one is much more efficient than the other. Numerous filter companies do not explain this, hence saying a filter is ‘5 micron’ may actually refer to a filter that is less efficient than a 10 micron filter, as the efficiency is key (10 micron at 99% efficiency could also retain more 5 micron particles than a 5 micron filter at 25% efficiency, as a rough example).
MANN-FILTER fuel filters are rated as per ISO Standards (ISO/TR 13 353 at 3-5 micron). PU 825 x is >95% efficient at this rating.
For info, the ‘825’ does not refer to the micron rating.