Changing the fuel filter

[Crispin]

So after the recent "issues" I had while driving I thought I would change the fuel filter for a laugh (after paying £32 for it, it was more like a cry...)

The filter has not been changed since I've had it (which is about 30-35k miles). I always run my tank bone dry. When I do fill up, I normally manage 75+L into a 80L tank. I know this is apparently bad but as I can't understand the logic as to why it's bad, I do it anyway.

So, back to the filter change.
After undoing the filter and the various wires attached to it (the filter top has a diesel heater in it!) it comes off quite easily.
Once off (and spilling a shedload of diesel out of the pipes and filter) I was surprised but the condition on the filter. it is rusted. The metal inner section (post filter I think) has a small amount of rust on it. The outer (tank side) had a huge amount of rust (what looked like flakes) and gunk.
When I opened the drain to see what would come out, I probably got enough muddy (it was brown and ugly) water coming out to fill a film canister with some to spare before diesel started coming out.

Once I removed the bottom drain assembly, I had a look inside at the element. It had globs of slim on it. Big chunky brown snot like things about the size of a 5p coin but with a fair amount of height. What the hell is that???

I put the new filter on, primed it for a while until it fought back and started her up. Fire first time and did not miss a beat.

So, I know diesel is hygroscopic but:
a) should there have been rust on the clean side of the filter?
b) should there have been that much water in it? The warning light has never come on.
c) What is the slime stuff? Aliens living in my tank?

Does all of this point towards "You should clean your tank out"? At only 85k miles in the rough outback of Hertfordshire, I would have have expected this..


Thanks
CP

 

[Andrew Prince]

Where's the pics?

Rust means there must have been water in there for a while - at least the trap is doing its job. Hopefully no rust particles have gone through the IP and injectors
The rust on the outside (tank-side) - do you think those flakes are from the filter body or have they come from somewhere else? Running the tank close to empty each time does mean that you suck up more of the dregs in the bottom of the tank. I would suggest that if you wish to continue this practice, it's worth changing your fuel filter a touch more regularly

The slime indicates diesel bug in your fuel tank - if it's made it through to the fuel filter, chances are your fuel pick-up will be covered in it. Definitely worth opening up and cleaning out the pick-up filter/gauze thing. If the slime/algae is bad, it might be worth dropping the tank and giving it a thorough clean out, given that you apparently have rust particles and other kak in there!

I'm pretty sure this is the source of your engine woes assuming that no damage was done by micro particles going through the injection system...

Cheers,

 

[Crispin]

Wife threw the filter away before I could take pics. Going to dig it out the rubbish now.

"Rust" might be a bit of a harsh term. It's more "the shiny part was not all shiny. I'll post pics.

The gunk / flaky stuff does not look like it is from the filter cartridge, if you wipe it away then it's shiny+rusty spots but not enough to account for it.

With regards to the running your tank dry - how is it bad? One can safely assume the pickup is at the lowest part of the tank ( ) so unless all this gunk floats, surely it's always susceptible to picking up gunk?

I'll have a look at the pickup next weekend and see how that looks.

 

[Andrew Prince]

With regards to the running your tank dry - how is it bad? One can safely assume the pickup is at the lowest part of the tank ( ) so unless all this gunk floats, surely it's always susceptible to picking up gunk?

The theory about it being bad relates more to using crappy fuel - not such a big deal in Europe - where impurities concentrate at the bottom of the tank (with the water) being heavier than diesel/petrol. You run the tank to empty and suck up the nasties and these nasties either clog up the filters, the particles scour the IP and injectors and so the theory goes.

The gunk is a different matter - it grows in your tank once you have the infection and will coat the fuel pick-up - as you say, this can happen at any fuel level. Running bio-fuel for the first time often causes it to all end up in the fuel filter (not sure precisely why). I think there is a chemical treatment you can add to kill the algae.

Cheers,

 

[Crispin]

Some pics:


There was a bit more on there which was quite loose. It's mostly gone with the whole dustbin experience.

A close up:

Two of the gogas:

(k, a bit smaller than a 5p coin. Wife tells me I have trouble gauging the size of things)



So, normal or not?

 

[Crispin]

They are organisms which grow on the water/diesel interface.

Sorry, but that is impressive. Some hardcore organism.

Evidence of bug contamination starts with brown / dark 'gunge' settling in bottom of tank - this is DEAD organisms ..... and is actually the problem that stops engines by clogging filters. The LIVE bug is not so much a problem.

So that is what the brown gunk is that came out with the water.

edit:

 

[Andrew Prince]

Yip it's a tough bug - funnily enough biodiesel seems to kill it or at least flush it out the tank. You'd think the natural stuff would be more palatable than fossil fuel!

The fuel filter looks very well-used Well overdue for a change

 

[Crispin]

to me.

How often do you change them? I thought it had a pretty long life?

 

[Chris]

I dropped the tank on LB and it was full of that black slime. The tea bag on the pick up was well clogged. Had a look in the 80 tank and it was clean as a whistle.

The pick up sits in a sort of bath. This stops dirt being washed into the immediate pick up area. But if you off road a bit, then everything gets a real shake up into suspension which can then drop into the pick up zone.

That filter look pretty poor. I had to drop 2 filers until mine was clear again. It did make a difference to the performance too. I guess it takes some of the strain off the pump as well. You need an endoscope down the filler neck!


Chris

 

[Andrew Prince]

I changed mine when I baselined my 80. Probably done 12k on the current filter - the old one looked like new when I took it off but I had no idea how long it had been on.

I think the service interval is probably something like 20-25k but will depend on operating conditions. One bad batch of fuel and you could be sitting with water in there for years until you change the filter. Probably not a bad idea to change it more regularly, maybe once every 2(?) years....
Seeing your filter has me thinking...

I carry a spare pattern filter in my 80 as part of my general spares - as a stop-gap if a bad batch of fuel clogs a filter. But I use a Toy OEM filter and will continue to use them.

 

[Paul]

Thats why i like the sediment type filters with a glass bowl, lets you drain off any muck but also lets you monitor the visual quality of the diesel.

 

[Chris]

Yep, I now have a clear in line filter fitted.

C

 

[Crispin]

thanks fellas. Will pull the pickup out this weekend if not too hungover.

I am guessing if I disturb anything in the tank (i.e. remove or clean the pickup) then I will pork the brand new filter I have on there with loose cr@p I'll move around. or not?

 

[Paul]

Could do, or take pipe off filter from tank and blow down it before putting it all back together, or even run some diesel down it to clear it.

 

[Gary Stockton]

And don't forget to release the hand brake too!!

I replace air, fuel and cabin filters every year regardless - gotta say that fuel filter looks like a left-over from the Ark ... Well used indeed!

Have fun dropping the tank. There is an inspection cover under the carpet below the left rear seat (ie 'passenger' side) that is easy to access, so that may be a good start before dropping the fuel tank?

Good result so far. What did you use to get that toothed plastic bit off the bottom of the housing?

Cheers

 

[Ecoman]

I get my fuel filter changed at every service. I know its a waste of money but its piece of mind and shows up any crud/ bacterial problems I may have in the tank.

 

[Crispin]

What did you use to get that toothed plastic bit off the bottom of the housing?

Cheers

I took the metal protective shield off and then some gas pliers to remove that. Was easy actually. Not entirely sure why they is that complex looking "grip" to it? Just above that there is a small knurled section which was fine.

 

[Crispin]

So got LC back from Mr-T today.

Process was quite simple:
1) Start undoing the tank guard.
2) Brush mud and sand from your eyes.
3) Undo more bolts
4) Brush more mud from eyes, was your hair, call customer and complain


Tank off, apparently there was more crap under the lift:

Inside the tank, nice and clean:

The pickup though was a bit more interesting. It, from the close up pics and what he was explaining, is a tube / cylinder / bucket inside the tank and the pickup is in this. Cannot quite work it out. Anyway..

Inside the "bucket" was some slime and... 3 tree leaves (type of tree unknown )

The sieve was totally blocked with "stuff". The clean parts are where he wiped it with his finger before the photos.

All put back together and enough diesel to get me to the local station, all seems well.
On the trip home it quite happily revved into the red without any issue so guessing it's all fixed.

I wonder if it was one of the leaves getting sucked against the strainer which caused the total loss that I sometimes got but then went away.

 

[Beau]

Did you put back a new filter, or just re use the old one.

Since owning my 90 series for the past 15 years, I have replaced the fuel filter in the tank twice, last time was last week when I though I had a blockage somewhere, turned out to be the filters in the injection pump were blocked.

 

[Crispin]

I replaced the filter in the engine bay with a new one. They used 3 cans of brake cleaner on the strainer to get it clean.
Not sure if there would be anything in the pipes which will block the new filter slightly. I've got a service coming up in 300 miles, I might take it off then and take a peak.