Mann filter - the good, the bad, and the very bad

[rv8ch]

I cut open my Mann Filter 940/4 yesterday and found some interesting things.

The good is that the anti-drainback valve works really well. After days of just sitting, it still had a lot of oil in it. This is not the same with a Champion, in my experience.

The can doesn't seem as strong as a Champion. When I used a strap wrench to remove it, it deformed the can. The rated pressure that the filter supports is fine for our application, but the can itself felt a bit thin and weak. No doubt the can is designed for internal pressure, not external, so probably not that bad.

The very bad is that the paper element had what I can only presume is a manufacturing defect. Very disappointing that for the last 49 hours I've been using a defective filter. I looked at the paper closely, and it seems like they probably use the same manufacturing line to cut filters of different heights, and they didn't retract the cutting wheel enough. I could see a line along almost the entire paper element. It "only" went through for a couple of inches.

 

[Dan 57]

Thanks for the report Mickey. It only seems cut a small fraction, so I don't think your precious engine suffered any ill effects.
IMHO I think that all those filters tests and research are overrated, as back in the days the filtering was done solely by the rather coarse reusable element, and engines did not die from bad filtration more than they do today...

 

[DanH]

The can doesn't seem as strong as a Champion. When I used a strap wrench to remove it, it deformed the can. The rated pressure that the filter supports is fine for our application, but the can itself felt a bit thin and weak.

Per the Mann catalog listings, the engine oil filter (W) has a max operating pressure of 14 bar, or 206 psi. It also has a low bypass opening pressure of 0.7 bar, or just a fuzz over 10 psi.

Now look at the filtration values. 50% at 20 microns is only a little better than a Champion (43% average, 74% when clean) and not as good as the Wix 51515 we tested (78% and 92%). It doesn't reach 99% until the grit is over 50 microns. That's not as good as a Tempest, Wix, or Champion.

The low max pressure and poor filtration numbers would strike it off my list, even if I was using an angle adapter with no bypass.

Some caution may be appropriate here. Mann lists a W940/4 (engine oil) and a WD940/4 (hydraulic system). At first glance it appears the specs posted to internet sites may be confused. The catalog says the WD hydraulic filter has a 2.5 bar bypass and a 14 bar max pressure. We have no idea about media restriction, but the micron values are no better than the W oil filter.

 

[rv8ch]

Per the Mann catalog listings, the engine oil filter (W) has a max operating pressure of 14 bar, or 206 psi. It also has a low bypass opening pressure of 0.7 bar, or just a fuzz over 10 psi.

Now look at the filtration values. 50% at 20 microns is only a little better than a Champion (43% average, 74% when clean) and not as good as the Wix 51515 we tested (78% and 92%). It doesn't reach 99% until the grit is over 50 microns. That's not as good as a Tempest, Wix, or Champion.

The low max pressure and poor filtration numbers would strike it off my list, even if I was using an angle adapter with no bypass.

Some caution may be appropriate here. Mann lists a W940/4 (engine oil) and a WD940/4 (hydraulic system). At first glance it appears the specs posted to internet sites may be confused. The catalog says the WD hydraulic filter has a 2.5 bar bypass and a 14 bar max pressure, but we have no idea about media restriction, but the micron values are no better than the W oil filter.

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@DanH - you clearly have access to better information than I do - I only have this: https://www.mann-filter.com/uk-en/catalogue/search-results/product.html/w940/4_mann-filter.html

Honestly, even if their filtration values were 10x better than the others, if they are going to ship filters with slits in the filter media, it doesn't really matter.

What I'm struggling with is how can a major brand like this have such bad quality control? I did see on this can that it was made in Argentina, and I guess it could have even been a counterfeit for all I know. My other Mann Filters are all stamped made in Germany, so let's see after I cut open the next one. I don't think I'll run it for 50 hours this time...