Fuel Filter Failure

[Warren Milberg]

In the ongoing thread on fuel polishing, a number of posters alluded to the potential for diesel fuel filter failure. I presume the filters noted were the pleated cartridge types used in the secondary of a Yanmar, and the replacement cartridges used as primaries for Frams, Racors and similar units. Please note the failure these posters seemed to be alluding to were not due to filters getting clogged with particulates/dirt/crud in the fuel, but rather the potential for these types of filters to simply dissolve, disintegrate, or otherwise come apart by merely being immersed in diesel fuel for some unspecified period of time.

The issue would seem to be whether a filter's time in service (whether the engine is running or not) is more critical to its potential for failure than fuel through-put measured by either volume of fuel filtered or engine hours. (in my mind, a clogged filter has not "failed," it has succeeded)

While anecdotal stories about such failures are always interesting, I would be more interested in factual stories about this type of filter failure as I plan to write an article about this topic. I would be curious to know (1) the specific brand/type of filter that failed; (2) how long it had been in use/service when it failed, and (3) the specific description of the nature of the failure, i.e., a pleat ripped, etc.

 

[Ross]

Warren I changed my filters last fall for the first time since I put the engine in service in 1999. My sediment bowl was always clean but on the basis of the horror stories posted here I made the change. As best I could see the filter elements in each unit were in good structrual condition. I don't regret the change and in the future I will probably opt for five year intervals. My fuel consumption rate is less than 10 gallons per year.

 

[kloudie1]

I have never seen one failed in that way, Warren.. Not to say that it can't happen, but you'd have to have a LOT of pluggage to collapse the media element....and a lot of pressure behind the fuel stream.. remember that the normal lift pump can only put out 6-10 psi..as limited by an internal spring. Some filter media will swell when hit with a slug of water.. I have seen some in industrial applications that swelled (swole?) enough to buckle the element from top to bottom, but these were about a foot tall. and so easier to buckle than something like the secondary on a Yanmar which is only about 2" tall. If I saw one crushed, I would first check to make sure that the element was not jammed on installation and crushed by tightening the housing.

 

[Stu Jackson]

Fuel filters

1986 C34; M25 engine; Racor 24RS, generally an average of a year but we put 200 engine hours in a year; have had boat for 11 years since '98, first change was after two years, then somewhat more often, but I've been going 150 - 200 hours with most of them.

No structural failures.

Some reports of damaged gaskets, but that's like my mom telling me to never buy a dented can!

 

[Scott T-Bird]

Recently replaced filters ...

We use our engine so infrequently that I had not been concerned until recently (after 4 seasons of boat ownership). The primary is a Fram Marine filter and the replacement filter part number was visible on the top (obviously Fram). The filter has metal sleeves covering the inside and the outside surfaces of the pleated filter element. The metal sleeves have holes .1" in diameter patterned throughout. I am sure this is typical of many filters. After reading threads about the micron rating of filters I was under the impression that you could get replacements of various micron ratings for various physical sized filters. However, when I went to the auto parts store and they looked up the part number, they informed me that the replacement filter comes in only one micron rating ... and in this case it is 10. So my primary filter is 10 micron. Other than gunk on the top and bottom surfaces, some gunky looking fuel and a little sludge in the bottom of the housing, the filter element looked to be fine except that it was dirty for sure.

The secondary filter, mounted on the engine between the feed pump and the injection pump had a filter element that was not marked but it looked clean. Here's where I am confused. The auto parts store I went to did a look-up for Yanmar engines and found a WIX filter that matched the physical size of the element that I have, a cylinder that is 2.7" x 1.4" in diameter. I asked about the micron rating to see if there was one with 2 or 3 micron. No luck ... this one has a micron rating of 19! It's not like they just wanted me to take what they had in stock because they had to order it anyway for next day delivery.

I bought it anyway but I also called Lockwood Marine who supplies parts for Yanmar engines. They had the filter in stock and told me that the micron rating is 8 when I questioned about it. When I asked about finding a filter with a micron rating of 2 or 3 as has been discussed frequently in this forum, the response was basically dismissive, as if I didn't know anything about what I was asking, which I don't but the whole issue has me confused because there has been a lot of discussion regarding the selection of filters based on the micron rating. I'm being told by the parts suppliers that my choice is to just take what they are telling me they have.

What gives?

 

[RichH]

Scott - What gives?

The filter industry, when building resin bound cellulosic filter media for fuel oils (a special technical 'paper') uses long thin fibers. These long thin fibers are laid down as a mat - meaning there are no 'round holes' to capture essentially 'round particles'. An analogy would be trying to filter golfballs with 'sticks'. 'Nutherwords' such filter material ISNT PERFECT in its retention; some cheaper 'papers' are very 'open' and use thicker fibers while that used by the 'high end' filter assemblers is fairly 'closed' and use thinner/longer fibers and is more efficient than an 'open' filter media. Plus, nowadays such filter paper has become a monopoly from essentially one worlds supplier ... and there are various grades of such paper all being sold for the exact same 'job'.
Filter ratings in such filter media is very difficult, and many filter assemblers cant even agree on the testing nor agree on the values of such even when the testing is standardized. So, for such filters the 'ratings' are entirely arbitrary based on the 'viewpoint' of the various manufacturers. Filtration ratings in such filter media is also 'fluid specific' meaning at a certain flow rate, viscosity, and pressure, etc. across the filter media you will get a set of retention values; but, change any of the 'specifics' and you can get entirely different results/ratings. Retention (via using a filter media with 'statistical pores' larger than the target particles) is by several mechanisms: 1. seiving - particles much larger than the statistical 'pore'. 2. Inertial impaction - moderately large particles coming out of the fluid stream when the fluid 'turns a corner' inside the filter media. 3. ADsorbption - where the negatively charged particles come in contact with the positively charged filter material .... and 'stick to it'. 4. Molecular attractive forces.

With respect to 'filter ratings of fuel oil filters' .... The best advice I can give (since I would entirely consume the bandwidth of this website in a proper technical explanation) is to simply buy your filters from a 'known entity' or 'reknown manufacturer': Parker/Racor, Wix, Fram, etc. etc. Personally I avoid 'engine brand filters' (vanity brands) as they BUY these filters from various sources (always at the 'best price'), and some of the these sources are 'suspect'.

This is the 'µM rating explanation' from probably the BEST and most reliable manufacturer of such fuel/oil Filters - Parker/Racor:

http://www.parker.com/literature/Racor/Mobile_The_Micron_Rating.pdf ... but even on this site from probably the leader of this type of oil/fuel filtration ... dont expect to gain 'an epiphany' to come away with a simple technical answer.

If you 'must' delve into the subject more deeply, consider to do a webseach/research for: (FILTER RATINGS + NOMINAL), (filter ratings + absolute), (filter + "beta ratio") ... the ratings schemes and methodologies: SAE J905, SAE J1488, SAE J1839, ISO 4020, "OSU-F2 test stand" .... and all this is only for FUEL and OIL filters as there exists a complete alternate universe for the rating of filters other than for FUEL and OIL filters.

Again, my best advice (as one deeply involved in 'technical filtration') is buy what you perceive is the BEST from the 'front line' automotive fuel/oil filter manufacturers such as Racor, Wix, Fram, etc.


BTW/FWIW - there are internet sites that supposedly compare various automotive service filters. These are usually 'slick salesman-talk' that baselessly 'slant' and misrepresent towards certain manufacturers, and that have absolutely no technical (filtration) merit, so beware.

 

[Cpt. Jon]

This is the 'µM rating explanation' from probably the BEST and most reliable manufacturer of such fuel/oil Filters - Parker/Racor:

BTW/FWIW - there are internet sites that supposedly compare various automotive service filters. These are usually 'slick salesman-talk' that baselessly 'slant' and misrepresent towards certain manufacturers, and that have absolutely no technical (filtration) merit, so beware.

Noted