Diesel algae.
   (Ver 1)


Having always been involved with petrol engines I had never heard of "diesel bug". When I did and put some treatment in the fuel tank of my AFV is when the trouble started. The treatment killed off all the bug. In doing so, I just speeded up the process, as sooner or later, the bug would have died and the consequences would have been the same.

Climate is probably the determining factor. In my case it was also the fact that I had a Detroit Diesel. In this type of motor, the injectors are fed more diesel than they can use.
The surplus diesel is used to cool the injectors and is pumped back to the fuel tank.
This gives condition (1) for the bug - warmth - our climate out here provides that by itself, but so does the engine.
Condition 2 is that the bug needs some moisture, condensation happens in virtually all fuel containers so it is normally present.
Condition 3 is darkness, normally the case in fuel containers.

So what you get is this nasty microscopic bug that lives on the surface of the diesel, but under the thin film of condensation floating on the surface. This condensation can be as little as a few molecules thick. So you won't know it is there.

It is not a problem till the bug dies, that is when you will discover this horrible gunk through your entire fuel system. It can best be described as like black spiderweb. It can sufficiently block fuel filters to the point they will collapse.

If any one of the 3 conditions above are not present, neither will the bug be. So, keep the fuel tank full to the brim or/and put in something to kill the bug. I am not even going to get into shining permanent light sources at the diesel!

The easiest way is to buy some "diesel conditioner" that specifically states it kills the bug and pour in the recommended quantity per fill and not worry any further. I have used a "Morey's" product, but I am told there are quite a few on the market.

I have been told, but have not confirmed it (so don't blame me) that 1% methylated spirits (wood alcohol) will do the same job if added to the diesel BUT, due to being alcohol it will dissipate over time.

I have mentioned just 1 of the 3 different types of bug that plagues diesel.

I believe that the people who have the most trouble with the bug are those blokes in the USA with the big triple motor off shore racing boats. Lots of use in the warmer weather, lots of humid air and no use over the winter, but large fuel capacity.

Pulling a fuel tank out of an AFV and trying to slosh clean it without being able to get behind the baffles is a right royal pain. You can do without the exercise..................

If you want to know more read on below. Alex being a mechanic goes into detail of the 3 different bugs. The bug my fuel system got appears to be the one he mentions as orange in colour. But I never saw anything orange, however, as it was already dead when the trouble occured and thus could have changed to a black colour, it may be the one.


Hormoconis Resinae

Green in colour, mats together as a fungal growth blocking fuel filters. Hopefully this is your problem.

Psuedo monas bacteria

Orange in colour and grows between the deisel and water at their iterface and has a very slimy texture appearance. It is caused by dead bacteria and combines with sludge causing blocked filters and irrepairable dammage to pumps and injectors. Hopefully this is not your problem.

Desulovibrio bacteria

Black in color and forms sludge on the walls of the fuel tank producing hydrogen sulphide and other acidic waste products. These contaminate fuel andcorrode the fuel system. Not your problem

Biobor is not recommended to clean out contaminated fuel systems that are contaminated with the H. Resinae. Biobor is also extremely expensive.

Keep fuel tanks as full as possible. Drain water traps before starting. Change fuel filters if the vehicle has been sitting for a long time. H resinae loves fuel filters and will stick like glue to it. H resinae is the most common problem and is too thick to penetrate to the injectors and in your case the injector lines under the rocker covers. It mainly likes to hang around filters especially the felt type ones.

My thanks again to Alex.


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