# Why no fuel filter?



## GFB (Oct 16, 2006)

Something that still bothers me is why my petrol engined 2.5L XT has no fuel filter - only a (regular, metal?) strainer or sieve at the pump in the tank. This just happens to be the first vehicle I know of with no replaceable fuel filter... Will this not increase the chance of problems with say dirt in the injectors, etc.?

Does somebody know the technical/engineering answer as to why Nissan can get away with a design like this? So far I could not get a good explanation from our local Nissan people. Maybe somebody has a manual describing the fuel system?

Thanks


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## LEONGSTER (Apr 9, 2006)

This is news to me. I was of the impresson it was part of the fuel pump housing, fully submerged in the tank?


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## aussietrail (Sep 24, 2004)

LEONGSTER said:


> This is news to me. I was of the impresson it was part of the fuel pump housing, fully submerged in the tank?



You're correct Eddie. It is indeed located there.


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## GFB (Oct 16, 2006)

Leongster & Aussietrail, yes, as admitted in my post, also my understanding is that there is a strainer in the tank. But, that is all. All other cars I know of has a strainer in the tank plus a replaceable filter (easy to reach and to be replaced at some service intervals). I would feel a bit better if I knew the "strainer" is not your usual metal sieve type but that it includes somekind of a micro pore filter element.

Did anyone had to get their in-tank strainer cleaned after prolonged use? 

Anyway, thanks for your replies thus far.
Regards


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## aussietrail (Sep 24, 2004)

GFB, Nissan refer to this "stainer" as the Fuel Filter and it is described as such in the electronic service manual. Getting to it and replacing it is not that hard once you pop the rear seat you will have full access to it. I believe this is a more advanced fuel filtering method than the old plastic type of fuel filter located in the engine bay.


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## GFB (Oct 16, 2006)

Thanks, Aussietrail - so I do understand you're saying an official Nissan manual calls it a Fuel Filter. Thing is, I have seen that on the computer system of the local dealer's parts counter the item is listed as a Fuel Strainer.

Would be interesting if somebody who actually have seen it, could clarify whether it is simply a very fine metal screen or not. I've indeed seen the mounting/access part to the fuel pump - easy to get there but one needs to make up a special tool to undo the big plastic ring nut (guess 120mm dia)...

I'm not necesarily saying this whole issue is a problem, but I would have peace of mind if I understand the engineering behind it. You know, I do have my doubts about cleanliness of fuel in some remote areas...

PS: Just again spoken to a workshop guy - he claims it to be a very fine nylon type screen.

Cheers


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## LEONGSTER (Apr 9, 2006)

Come to think of it, you are right.

Some months back I removed my fuel pump assembly to access the tank and recalled seeing a fine nylon mesh bag at the base of the assembly. I assumed (incorrectly) that this was the strainer/pre-filter that is attached to most fuel pumps. 

But from what you've described in your latest post that WAS the fuel filter.

 

At 20,000 + km mine looked pretty clean, but short of seeing it under a microscope I guess there's no way of telling.

Don't worry too much about it though. Just watch the fuel you put in.

(Easier said than done I guess.)


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## lanie49 (Jan 13, 2007)

Gooday chaps, is this filter a wash and re-use or a chuck out item ?
Expensive to replace every 20/30000 kms ?


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## LEONGSTER (Apr 9, 2006)

lanie49 said:


> Gooday chaps, is this filter a wash and re-use or a chuck out item ?
> Expensive to replace every 20/30000 kms ?


Honestly, I wouldn't know. It seems to be made of a cream colored, pretty tough, polymer-based material not unlike very fine mosquito mesh so I guess you could always reverse flush it. If it were a replaceable item I would imagine it shouldn't cost more than a standard in-line filter...

My real concern is how long the standard fuel pump is known to last. Given that the X-trail has no return fuel line, the pump must have to work very hard.


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## ALO4X4V (Oct 13, 2006)

GFB
There is definatly a fuel filter that needs to be replace at 100,000km and it's not cleanable.(It is called a strainer in Australia as well) And the no return line is due to the system being pressurised so it delivers fuel when needed it also means that the fuel is delivered cooler other than going back to the tank and completing a loop in turn heating up the fuel in the tank it is a miror temp increase but still an increase
Dave


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## GFB (Oct 16, 2006)

Dave 
It seems difficult to settle this filter issue! May I ask what is the source or reference of your replacement remark? - I ask so, because according to the Nissan service manual I have seen, the fuel filter is a "maintenance free" item... But, I tend to believe one might have to wash it out at say 100 000 km's - if you happened to have made use of not-so-clean (rural?) fuel supply. Nobody clearly said so, but that's the impression I got from the workshop guys at the dealer...

Cheers
G


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## ALO4X4V (Oct 13, 2006)

GFB,
We service x-trails at work and we use a generic servicing manual that covers specifications on all makes and models timing ,A/C specs,oil/coolant capacities and when to change what filter and suspension setups and so on. There is a paper element in the sealed fuel filter/strainer and it would filter in in microns so the last thing i would be doing is back flushing a fuel filter when you only need change them a 100,000k's. The orange element inside does not look to orange when you cut the filter in two hope this helps 
Dave


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## GFB (Oct 16, 2006)

Thanks, Dave. The presence of a paper element is both interesting and confusing news... 

The slightly clashing bits of info makes me wonder whether it could not be that the specs/filter differs according to country or region, and/or year model.

Anyhow, seems quite sure that there is no short term worries!


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## Sean King (Jan 12, 2006)

Hi guys,
I had to change the entire fuel pump and filter a couple of months ago due to poor acceleration and water in my fuel due to bad gas at gas stations.

The fuel pump is located in a hard plastic cylindrical housing which is submerged in the gas tank.The fuel filter is a porous mesh bag which can be replaced.

However I got an adaptor made using the same design of the high power hosing that supplies the fuel to the injector rail.

Now I have a replaceable fuel filter before the injector rail since this mesh fuel filter located in the tank attached to the fuel pump is not adequate for all filtration.

This has helped the performance of the engine considerably.

It's quite easy to install once you have a good hydraulic pressure hose technician.Anyone who makes hydraulic pressure hoses should be able to come up with an adaptor to use on your fuel system hoses.

So along with the mesh bag (filter) in the tank I also have a changeable steel fuel filter.


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## LEONGSTER (Apr 9, 2006)

Sean King said:


> Hi guys,
> I had to change the entire fuel pump and filter a couple of months ago due to poor acceleration and water in my fuel due to bad gas at gas stations.
> 
> The fuel pump is located in a hard plastic cylindrical housing which is submerged in the gas tank.The fuel filter is a porous mesh bag which can be replaced.
> ...



DriftKing has posted some useful info in the XT forum under " maintenance-free fuel filter". Suggest you take a look at it as he discovered that the white fuel pump housing actually does contain a paper element. I believe ALO4X4V noted something similar earlier in this post.


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## GFB (Oct 16, 2006)

Leongster, both you and Sean King clearly referred to a "mesh bag". This sounds so vastly different from what we have seen in DriftKing's thread... Therefore, again, could it not be that the older (or 2.0L) models have a different kind of fuel filter?

Just wondering.

Cheers


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## LEONGSTER (Apr 9, 2006)

GFB said:


> Leongster, both you and Sean King clearly referred to a "mesh bag". This sounds so vastly different from what we have seen in DriftKing's thread... Therefore, again, could it not be that the older (or 2.0L) models have a different kind of fuel filter?
> 
> Just wondering.
> 
> Cheers


Based on the findings of DriftKing, it now appears there are TWO filters in the XY's fuel system both of which reside inside the tank.

The Pre-Filter is a sieve-like, purse-shaped filter made of some kind of nylon mesh. This is exposed and can be seen when you've removed the entire fuel pump/filter/sender unit.

The Main Fuel Filter is made of some sort of fibre (cellulose perhaps) and is a sealed item inside the fuel pump/sender unit housing. The entire housing is apparently replaced in its entirety, although I do not know the part number.

A new housing is evidently pale cream to white in color, and gets progressively darker with contamination.

The problem is, I suspect, the entire filter unit is only ever replaced when the fuel pump fails.

Preventative maintenance - by replacing the filter at regular intervals (50,000KM?) should improve the life of the fuel pump. Again, the actual replacement interval would depend on the quality of fuel in your area.

The only way to check is of course to remove the entire unit and check the color, which is a pretty dangerous job in itself.

Hope this helps.


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## LEONGSTER (Apr 9, 2006)

I have every reason to believe the same fuel pump/filter/sender unit is used in the 2.0 litre and 2.5 litre XY's. 

(The only component that MAY be different would be the fuel pressure regulator, although I do not know this for a fact.)


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## Sean King (Jan 12, 2006)

I have every reason to believe the same fuel pump/filter/sender unit is used in the 2.0 litre and 2.5 litre XY's

Yes you are right. The unit is the same for all X-trails since it is also the same for the Nissan Primera new model vehicles which also use these same types of engines QR20 DE and QR25 DE gas engines.

The Nissan Dealer here in trinidad states that the fuel pump/filter/sender unit is the same for the old Xtrail Model right up to the new one.

The Strainer is a white plastic see thru cylindrical unit that when you look at it you can see if the strainer (filter) is dirty and needs to be changed.

This entire assembly is shown in detail in the CD Workshop Mannual which you can obtain on ebay at a nominal price and it shows the different pieces that make up the entire fuel pump/filter/sender unit .


I hope this helps.


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