This is one part of the servicing I’ve been putting off for a while. It just looked a little complicated to me and when you start playing about with fuel lines and things it worries a relative newbie with the spanners. Anyway, it had to be done and I was determined to do it myself, so here’s the write-up with some pictures.
As usual with the Pajero there are several theories on how often the fuel filter should be replaced. These include: Every 12 months, every 40000 miles, only when you think it might be causing a problem. At this point for me I don’t when the fuel filter was last changed (if ever) so I need to do it now for peace of mind. Then I can decide how often to do it in the future at a later point.
The first thing you have to do when performing a Pajero fuel filter change is to find the bloody thing! Here’s a photo of where the fuel filter is located on my 2.8 before I remove anything:
As will become obvious in this write-up you need much more access than is available at this point. You at least have to take off the intercooler (big silver/black thing to left) and those who have two batteries as I do often talk about removing the battery nearest to the filter as well. I managed just fine with only removing the intercooler. If you don’t know how to do this, have a look here first: Removing the Pajero Intercooler
Once the intercooler is out of the way we can see a much better view of the fuel filter which is arrowed below.
Right, now we can see the thing we need to remove the 2 fuel pipes. These are pretty obvious to see, coming off the front of the fuel filter unit. In theory you can do this with a screwdriver but I found it easier with a socket. Once removed there will be a little diesel leakage from the pipes but not much when I did mine. Note: you might wish to label these pipes before you remove them so you know which goes where when refitting.
Now it gets fiddly. Have a look down the back of the fuel filter housing and you should see the 2 bolts that hold it all in place. A socket extension was called for here – remove the 2 bolts.
Pull the whole fuel filter unit away from the bulkhead carefully and you’ll see that it is attached to 2 electrical clips. Undo these and try not to get diesel into them as I’m reliably informed this can damage the seals inside. You should now be able to take the whole fuel filter unit away from the vehicle, watching out for the diesel spilling out.
Ideally you have a vice available at this point. Otherwise you’ll have to improvise. Keep the unit upright and place the plastic water sensor (right at the bottom) very gently in the grips of the vice – just enough to get a hold of it (see photo below). Twist the filter and housing anti-clockwise to loosen, but not remove the plastic water sensor.
Now open up the jaws of the vice and grip it tightly around the body of the fuel filter itself (not the top housing). Twist the top housing anti-clockwise to remove the fuel filter. Drain any diesel from the fuel filter now. Then unscrew the plastic water sensor all the way out so it’s removed.
Here’s a photo of the whole thing taken apart. Left to right: New Mitsubishi fuel filter, old fuel filter, fuel filter housing. Bottom: Water sensor. Also notice on the water sensor the arrowed o-ring. In the box of the Mitsubishi fuel filter that I bought there was a new o-ring to go here which I obviously replaced. Not sure if this is the case on an after market fuel filter?
Let’s put it all back together!
Put the new o-ring onto the water sensor and then screw this into the new fuel filter. I couldn’t find out how tight this is supposed to be really, so I did it as tight as I could with my fingers and then gave it a final nip in the vice.
Now open up the vice and hold the fuel filter itself in place and screw on the filter housing. Again there’s no real test of how tight, it’s a guess really.
Right, now we’re ready to go back to the truck with it. Hold the unit roughly where it’s going to sit and put back the two cable clips you removed before taking it out. Then put back the 2 bolts at the back and tighten them up.
Now we need to put the fuel pipes back onto the front of the housing. Mine had these old clip things that I tried tightening but after a certain point they just seemed to spin. I really wasn’t confident about them so I replaced them with some small jubilee clips. My local motor factors had them labelled up specifically as fuel line clips.
At this point we’re almost done, but the fuel filter needs ‘bleeding’ to pull through the diesel and and fill the unit with fuel, therefore removing any air. The manual I followed showed a fuel filter housing with a different pump and air plug arrangement to mine, so I can only describe how mine looks and works. Yours might be different, but the principle’s the same.
I’ve shown a close up of the top of my filter housing below to show the relevant parts. Unscrew the white disc on the left which is the pump. Now undo the bleed screw (a few turns) which is the big nut in the centre. Work the pump until until fuel without bubbles comes out of the bleed screw. Now tighten the bleed screw and pump again until resistance is felt. Now tighten up the pumping disc.
Have a final check to make sure everything you took off is back in place securely, then put the intercooler back on. Now fire her up and off you go.
All in all a job that I needn’t have been worried about at all that could be done from start to finish in about half an hour with a little experience.
I’d love feedback on this post. What do you think about what I’ve written? Any tips on how to do it better/more efficiently. Anything you think I’m doing wrong? Please let me know in the comments box below.