Fuel tank level sender and tank cleaning.

[JnJ]

Hi
Was having fuel problems caused by blocked inline filter , so decided to remove tank still in process rain stopped play.
When I removed fuel level sender I noticed there was no o ring on it.
Should it have one ?

Have nearly drained the diesel out,very slow out of supply pipe but pulled other one and flowed out freely
Will try get tank out tomorrow any suggestions how best to flush it out?

190d 2.5 1988 tank I think is plastic.
Thanks in advance
John

 

[Smiley]

If you are getting badly blocked filters on a diesel car then the cause may be a diesel bug problem - it is more common in the marine world but can also happen with cars usually when left unused and condensation has built up in the tank. The diesel bug itself is an algae and will keep blocking the filters until you get rid of it completely. You can buy diesel bug treatment from marine chandlers.

 

[JnJ]

Thanks for that Smiley.
Got tank out, filter blocked don't know how it ran.
Did a 200mile trip last weekend not surprised inline filter looked bad.
Load sludge dropped out of tank when I moved it after took tank filter out yuk.
Clean tank next job .

 

[Smiley]

That does look like diesel bug. You will need to get the treatment to get rid of it - it is no good just washing out with diesel.
Has the car been standing for a while unused?

 

[JnJ]

@ Smiley yes I agree looking into it.
It had stood a few years before I bought it plus it wasn't used regularly when I first acquired it. The car now gets used regularly about 5k miles a year, it's been a reoccurring issue over the last few years,have run diesel injector cleaner through it in past.has helped .
Didn't realised this could happen, life but not as we know it in my tank.
Was advised to get injectors done as engine sounded like tin full nails until warm.

So this time had injectors reconditioned, new oil and filter,fuel filters, its annual treat,ran great.
Idle was still rough though loads quieter more go if one these has any! and more mpg great.
Still also a bit noisy but it always had been.
Idle got worse and lost power and stopped.
Looked at inline filter it was clogged.
Hence where we are now.
I shall get some bug killer and use it when I get it back together.

 

[m80]

What you're looking at is the excreta produced by the 'diesel' bug.

A full tank is less likely to allow the bugs to develop.
It will grow in the water that rises to the top, and eats the diesel for nourishment.

Once there forget treatments. M16 is used widely as a prevention. Others can cause the dispersal, and limited breakdown. But generally expect the bugs waste to block any filter.

In well used cars the constant replacement of fuel prevents the development.

Unless you intend to leave the motor unused treatment isn't needed.

In theory clean diesel doesn't need to be disposed of.
Tbh, I would clean all
New filter.
Put any good diesel back in assuming there is enough to be of a value greater than a new filter.
Run a tank through it and replace filter again.
But I wouldn't blame you if you binned all the old diesel.

 

[Smiley]

I had the same problem in a 124 300d years ago.
I got a small bottle of diesel bug treatment from a marine place; used it as instructed, cleaned the tank and the lines, replaced the filters, got rid of the old diesel and the car has been fine ever since - the guy I sold it to still has it about 8 years on - the problem never came back.
After that experience I will never put diesel from a spare can into a car - you never know if the bug is in the can and it is hard work to get rid of it completely.

 

[m80]

If the diesel bug is present the black crud at the bottom of the container is the evidence.

 

[JnJ]

Thanks for that info m80 ,Smiley.
I will bin the old diesel only 2 gallons and bit came out.
Ordered some treatment thanks m80 for that info.
Don't wish to do this again ,getting the fuel supply pipe and other off bottom tank I did not enjoy no room and diesel all over my arm swbo (she who must be obeyed ) was not amused when I came in!.....
Here is picture of sender stripped to clean out black sludge. It never had the reserve light work it comes on when ignition turned on then never shows when empty so I assumed the black good was stopping it going all way down.

 

[m80]

Bear in mind the treatment mixes with the diesel to make it unpalatable to the bug.
In a marine fuel tank it's common for each tank of fuel to be treated. But really that's because the boat can be left unused for significant periods. There have been accusations of remote marina's pumping contaminated diesel into a boat, but we shouldn't need worry about that.

 

[JnJ]

Well I'll try to avoid filling up at a marina in the future.
So far tank now cleaned and dried out,some slimey brown black goo came out so I assume the brown is alive and the black is dead.
Like trying to hold frog spawn.
Received bug treatment.
Got new o rings, can see why they recommend to replace..
Old one on left new on right in pic.

 

[JnJ]

Just to say thanks
All back together and running even got the fuel level reserve light back working.
The sludge inside fuel level sensor was stopping the float going all way down to the contact,also giving a false reading for low fuel levels .

 

[Gnasher141]

Reading the posts above, it can come across that the bugs are little creepy crawlies that crap out waste. The “bugs” are in fact like a bacteria or fungus that forms and thrives in the water/fuel interface and can cause serious corrosion to steel tanks and this is where a lot of the brown colour comes from. If discovered it is best to get rid of all water/moisture and use a biocide to kill any remnants.