Is my air filter already dirty?

[Eren]

I have MAN diagnostic screens that give me loads of instant technical info about the engines while on the run. One of the data that they provide is “Air pressure after filter”. So it measures the pressure at the space between the filter and the turbo. It used to be 0 or -1 bar, whereas the last time it showed -2 bars (on both engines). With simple thinking, I understand this as the filter is getting clogged and it is getting harder for the engines to breath. At the same screens, there are 3 lights on the right side of each parameter, green, yellow and red. As all may guess, green says “all is OK”, yellow says “not so much” and eventually red is alarm.

In all my boats it has been a question for me to guess when to replace the filters. Do you think that this “air pressure after filter” parameter is good for deciding for replacement of filters?

 

[Portofino]

I,ve got an earlier version however it displays “ air suction pressure “

As you can see 30 mbars

I go by the colour like to see them yellow/ white ish clean


Not like a theses which looked clogged to 8uggary !


In the 5 years of ownership I,am on my 3 rd set fitted last Sept .
Reason I was in Romeo marine in Cannes buying some other stuff and happen to notice they stocked them priced at € 70 or something, so snapped a couple up and fitted them .
Previously I ve been invoiced €190 each - ouch !

How long have you had the current set and do you have a “tell and show “pic ?

 

[Eren]

Well, mine cost above EUR 500 each, so I really want to know when I really need to change it.

I don't have a photo but their color is somewhere between your first and second photo. And I am a bit angry why we cannot be a bit more scientific if our engines are equipped with such nice reporting screens? These screens are designed for the use of captain/owner but, I cannot find any reference guide that explains how to evaluate the data provided by these screens.

Coming back to the filters, MAN service schedule says 400 hours or every year, whichever comes first. I changed them 2 years ago and clocked 210 hours on them. I feel like it is still early for replacement yet. As I said, I am searching for more scientific input to give a correct decision.

 

[markc]

Mine (MTU) have a tell-tale indicator on the top of the filter that shows red if they need replacing. I had an exhaust leak last season and knackered all 4 very quickly! BTW, it's worth shopping around as I found the same as OEM supplied for less than half MTU's price

 

[Portofino]

Ok test the “ we are German and therefore masters at engineers “ theory by wrapping some temporary gaffer tape around one sides filters say 1/2 coverage and watching to see if you get an amber or red led ?
Note the pressure reading- does it actually change??

How much headroom is there ?

 

[Eren]

I thought about the same and will try it. I think I am on the correct track with using this data to decide on filter change time. I found the below data for mtu engines on the web. The table gives reference conditions for several parameters on the engine. And it directly relates “Intake depression” data (which is same data that I get as “air pressure after filter) to new filter.



At the second column, “A” stands for “Design value”, “L” stands for “Max permissable limit”. So for this specific MTU engine, if the minus pressure reaches to 50 mbars, the engine cannot breath well and it is time to change the filter. At MAN, they indicate the limits with yellow and red LEDs. I plan to wait until the yellow light is on.

 

[Eren]

Mine (MTU) have a tell-tale indicator on the top of the filter that shows red if they need replacing.

That is quite good actually!

 

[BartW]

I replace the air filters every year,
Just for peace of mind,
I buy them from MAN at 75,- euro pp ex Vat.

Here is a picture after 160hrs running time




And this is when new,

 

[Bouba]

Well, mine cost above EUR 500 each, so I really want to know when I really need to change it.

Eren, is that a mistype? €500!!!

 

[Eren]

Unfortunately not... That is why I want to get the most out of them.

 

[BartW]

eren,

just a quick google,
the MAN part number of your filter might be : 51084010003

https://www.ricambimotorimarini.com...ers/air-filters/air-filter-51-08401-0003.html

there is a OE filter manufacturere (coincidently name is MANN, they have a replacement for that: C 37 820/1 - Air Filter
https://spareto.com/oe/51084010003

 

[Bouba]

Unfortunately not... That is why I want to get the most out of them.

Can you clean them with compressed air?

 

[Montemar]

Try these people:-
https://www.inlinefilters.co.uk/
You can search air filters by size then have a close look at the specifications to see if it will fit.

 

[Eren]

eren,

just a quick google,
the MAN part number of your filter might be : 51084010003

https://www.ricambimotorimarini.com...ers/air-filters/air-filter-51-08401-0003.html

there is a OE filter manufacturere (coincidently name is MANN, they have a replacement for that: C 37 820/1 - Air Filter
https://spareto.com/oe/51084010003

Thanks a lot Bart, that is great input for me!

 

[Eren]

Can you clean them with compressed air?

I dont think that it may be possible. As far as I see it does not look like a regular air filter. However I will check for long life substitutes like K&N filters.

 

[Eren]

Try these people:-
https://www.inlinefilters.co.uk/
You can search air filters by size then have a close look at the specifications to see if it will fit.

Thanks, I will have a look at it.

 

[BartW]

Can you clean them with compressed air?

I think that the dirt in a boat's airfilter is mainly soot,
the particles are extremely small size, and stick between the fibres of the filters
when you apply air pressure enough to get the dust particles out you will damage the filter / fibres,
so in practice, its impossible to clean them
all imho

 

[Bouba]

I think that the dirt in a boat's airfilter is mainly soot,
the particles are extremely small size, and stick between the fibres of the filters
when you apply air pressure enough to get the dust particles out you will damage the filter / fibres,
so in practice, its impossible to clean them
all imho

That’s a pity, because of what he has to pay for what is essentially paper. I mean I can buy a first edition Gutenberg Bible for what Eren forks out for those filters:ambivalence:

 

[Eren]

I have MAN diagnostic screens that give me loads of instant technical info about the engines while on the run. One of the data that they provide is “Air pressure after filter”. So it measures the pressure at the space between the filter and the turbo. It used to be 0 or -1 bar, whereas the last time it showed -2 bars (on both engines). With simple thinking, I understand this as the filter is getting clogged and it is getting harder for the engines to breath. At the same screens, there are 3 lights on the right side of each parameter, green, yellow and red. As all may guess, green says “all is OK”, yellow says “not so much” and eventually red is alarm.

In all my boats it has been a question for me to guess when to replace the filters. Do you think that this “air pressure after filter” parameter is good for deciding for replacement of filters?

A quick note about my above question:
It is confirmed by MAN engineer that “Air pressure after filter” (or “depression”) parameter is directly gives information about how dirty the air filter is. On my case I decided to get spare air filters, wait until the warning light turns to yellow and will replace them. By this way I will be maximizing the healthy life of my air filters.

 

[BartW]

A quick note about my above question:
It is confirmed by MAN engineer that “Air pressure after filter” (or “depression”) parameter is directly gives information about how dirty the air filter is. On my case I decided to get spare air filters, wait until the warning light turns to yellow and will replace them. By this way I will be maximizing the healthy life of my air filters.

it would be interesting to learn at what pressure the yellow light turns on