The Mitsubishi Pajero Owners Club®

[Enjoymyswb]

I have done a little search and only come up with a couple of post regarding additional fuel filters for the 3.2.

After the scare of a potential new fuel pump I though it might be worth investigating the possibility of adding an additional fuel filter, wonders if anyone had done this, any advice on type and where to add in, pics are good 😀

Thanks all

[Google]

[Rob546454]

You can buy in-line fuel filters, as in just cut the pipe and stick it inbetween. I would do it after the standard one. Not sure if that would be of any benefit as I don't know the cause of the failure.

[mof000]

Is it not just a case of making sure your fuel pipes and fuel filler pipe are in good order?

[tom fenton]

Yep I agree. Ensure fill pipe and breathers in the wheel arch are good. Change the main diesel filter regularly.

[Enjoymyswb]

Thanks all

I'm pretty sure the fuel filler and breather were replaced a while before I had it and looked quite new, but looked again and look pretty rusty.

I have drained the filter and a few very small bubbles of what I would suspect is water at the bottom so may be getting in somewhere, or maybe the fuel tank has never been drained and has some water in it.

I think my plan will be have a closed look at the fuel pipes and breathers again, and drain the tank when fuel level is down and take from there, any top tips of where the fuel breathers generally rust through (though understand could be anywhere) especially under the arch, poor design I personally think!

[SteveW-DID]

The fuel pick up pipes on the tank are a real problem not just the filler pipes. Also replacing the fuel filler pipe on its own and doing nothing with the through the chassis pipes is a waste of time. My advice would be to get it all off and have a look.

[Enjoymyswb]

Well, I pulled the fuel line not noting of any concern that I could see, I also took a small sample from the tank an no water seemed to be present, and tiny whisper of dirt maybe.

When I drained a maybe a quarter pint max from th fuel filter there is are a few very small what look like bubbles of water, is this normal or a concern, don't worry about this is just normal, I guessing that there will always be some moisture in a fuel system but the fuel filter bowl should collect it?

Any thoughts?

[assassin]

Its normal, with diesel you get a quantity of water either from the filling station tanks or condensation.

During cold or variable weather any air in the tank contains moisture in the air, as temperatures fluctuate due to weather and warm fuel going back to tank any airspace is cooler as is the tank body, condensation from the cooler air forms on the inside of the tank and forms little water globules, over time these run down the inside of the tank and into the fuel and it settles on the bottom of the tank as diesel floats on water and you get a layer of water on the bottom of your tank. Your pick up pipe sits nearly at the bottom of your tank and as the water levels increase as time passes your fuel pick up pipe pick up a mixture of this water and diesel.

Your diesel filter contains two parts, the agglerometer section which filters out the water and the filtration section which filters muck from the diesel, the water sits in the bottom of your fuel filter which is why you have a drain plug, to drain this water out.

If your fuel tank becomes laden with water and sucks more up with the fuel the agglerometer section of the fuel filter becomes full and if you have a warning light it will come on telling you your fuel filter needs draining, if it isn't fitted with a drain warning light it overwhelms the diesel filter and just goes through in the fuel.

Two simple things to help prevent it:

During wet or wintry periods always keep your tank full, keeping it full reduces the amount of airspace and reducing the airspace means less moist air in the tank to condense into water and settle in the bottom of your tank. Drain or change your fuel filter more often, for what Milners or other specialists charge you can often buy two or more fuel filters for less than one OE part from the manufacturer.

If you stand a vehicle with a high water content in the fuel tank for a prolonged period you get a condition called diesel bug, this is essentially a bug which sits on top of the water and below the diesel and this forms a black sludge as it reproduces and dies off, any thick black sludge and suspect diesel bug, we get a lot of it on boats and any boat owner will know this condition.

[Enjoymyswb]

Thank you for this, really helpful reply, owned her for a while now but still learning

[VIKI]

Most grateful for all your knowledge "assassin "; do you think adding extra inline filter with plastic insert will help protect injection pump? If so where is best place to fit it? On fuel line which goes to normal filter or on returning line? Any advice on fuel filter brands? I was also wondering fitting a plastic filter like this from HGV which is design as far as I know to catch water and big debris from fuel it's fitted before normal fuel filter any thoughts about it?

[assassin]

Yes, learn from expedition vehicles such as my own which uses marine technologies.

In many parts of the world they carry diesel in rusty old drums, dirty drums, and then cut it with whatever they have to make it go further, and often water based cleaners as they break fuel down and it absorbs water so you get a combination of dirty diesel carrying lots of solid contamination, then with cleaner and water added.

Marine filters come in different types, individual units come as plain filters to filter out crud, agglerometer to separate water, and both versions come as pre filter versions which are not as good filtration wise but fetch out much higher quantities, or you can get a combination unit with both pre filters and normal filters in a common housing.
Bear in mind boats are much more prone to water contamination from their moist environment, most use a double pre filter unit to filter out large quantities of water and crud and have clear plastic bowls, you can look in the filter side and see how much *beep* it has filtered out and in the agglerometer side to see how much water it has filtered out, these combination units are massive due to the amount the pre filtering stage removes and this is around 95% + of the detritus and water.

These then go to the normal filters which again are a combination filter containing a normal filter and separate agglerometer exactly as the pre filters but are much smaller, where as your normal fuel filter has the filter and agglerometer combined these are separate mounted on a standard housing, and you can see how much water is in the agglerometer side and how much crud is in the filtering side.

Bear in mind by boat has 2 X 1200 HP Mitsubishi marine diesels and the fuel tanks size means I don't buy diesel by the litre or gallon, I buy it by the ton/tonne as it is a lot cheaper so you can imagine the air space in my fuel tanks as I run it down until I can buy 3 tonnes to fill the tanks, the filters are massive, the pre filters containers hold 25 litres each and the normal filters hold 5 litres each.

Manufacturers do much smaller units as smaller marine engines are based on industrial versions of automotive engines, you can get marine versions of most Ford diesel engines, BMW diesel engines, Toyota diesel engines, and many more for smaller boats, hence much smaller filters to fit these engines.


With the expedition boys, they often had crud and water in their cut diesel so combination units were fitted, two versions existed and the first was to remove the original fuel filter assembly and replace it with a combination unit having a separate agglerometer unit fed first and feeding the filter unit second, these were fitted when they were going to countries where the cut fuel in rural areas could be a problem and were easy to use as you simply lifted the bonnet and looked at the clear bowls, if one was over half full you removed it, emptied it out, wiped it, replaced it and you were on your way. You could also monitor the quantities of water you filtered out by the rate it filled, so easy to use, the filtration side worked in exactly the same way so they were easy to use. Where they went to countries where cutting fuel was endemic a combination unit pre filter was fitted to the chassis and heavily protected, as time moved on they became available with sensing which told you they were 75% full so I would suggest something like this, most manufacturers make something similar and they are easily fitted, be aware you need room to see and remove the bowls and they need impact protection if under a vehicle.

[VIKI]

I was thinking about Delphi double filter unit DFA07 with 2x HDF 296 filters over 2 transparent water bowls but don't have a clue if they be fine as normal under bonnet filtration unit or should I keep orygial filter on and just add this Delphi unit before it? Dear Assassin can you give me some quality /price advices on unit which could be either stand alone filtration setup or just extra add on before orygial MMC filter holder? What option in your opinion will be better choice for pump safety and reliability of vehicle (Shogun V78 3.2 DID, prelift model) Many thanks for all advices on that?

[assassin]

Prices vary, always use a micro version as all manufacturers now supply them and I would suggest fitting them under the bonnet between the tank and fuel filter and keep the original fuel filter as you can have too little filtration, but not too much.

[VIKI]

Sorry for daft question but what does you mean by "micro version "?? So I shouldn't be worried about fuel flow as I be adding extra 2 HDF 296 filters on fuel lines before normal fuel filter assembly?

[assassin]

They come in different physical sizes and with different flow rates, try putting my boat pre filters under your bonnet and you would have to take the engine out to get then in. These are the larger sizes for larger engines, smaller engines use smaller sizes usually called medium and automotive engines use even smaller ones and most manufacturers call them the mini or micro range depending upon their range.