Updated: 5 days ago
Some readers may recognize the term Snake Oil, the American slang given to medical products with dubious and unverifiable benefits in the late 1800s. Following years of questionable benefits, dubious recommendations and wild claims, fuel additives are often viewed in the same manner.
I spent many years at sea rising to Chief Engineer in the late 80’s. During that time only very occasionally did I see lacquering on fuel pumps but never Diesel bug or lubricity problems. Diesel had not changed for decades and the engines were simple. Yet there were constant recommendations to dose with ‘fuel saving’ and ‘sludge busting’ additives amongst others, at dose rates so small they would bemuse the best brains at NASA. Any additives required were put in by the suppliers, after all margins and business were good.
Can diesel fuel additives improve engine power?
Have you heard the... "Increase power and get fuel saving up to 10%" - How? If it was that good no one would have to sell it as owners would be beating a path to the supplier’s door. The reality has left few seeing any benefits and resulted in the belief that additives were deemed expensive and unnecessary.
Diesel is no longer made from easily sourced sweet crude.
Fuel has changed completely, refiners are constantly under pressure to cut costs. They now refine 80% more from a barrel of crude than they did in the 1980’s and these barrels originate from fields which were deemed uneconomical and of poor quality in the 90’s. As a result today’s crude has more sulphur and undesirable elements which pose greater challenges to the refiners as they endeavour to supply a product to meet ever increasing environmental legislation and the demands from the engine builders. All at a time when fuel margins have been squeezed to a minimum, business is not so good now and additives are a cost, so only the bare minimum is added to meet specification.
The Truth About Additives
For decades there have been two additives readily available, one to apparently "save fuel consumption" and one to "kill Diesel bugs", and a multitude of suppliers who promised everything from both. The engine builders now make smaller, lighter, cleaner engines with massive leaps in technology yet the humble diesel by contrast has been getting worse.
So now, finally, there is a need for well chosen additives that can play a very real part in modern diesel. Tackling lubricity, deposits, cold flow or cetane reduction amongst others they can ensure the diesel is maintained, slow degradation and prevent the inevitable deposits from low sulphur diesel.
Did you know all the fuel manufacturers recommend a maximum life of 6 months for diesel? After all, they make diesel to burn, not to store for months or even years at a time...
Sludgy Filters and Deposits
If you have sludge in your filters then yes you need to look at your tank as you may have ‘Diesel Bug’. There are two types of diesel bug treatments; enzyme and biocides. Enzymes don’t kill the bugs, they remove their food. Biocides kill them; they act like the antibiotics we use when we have a disease.
But is the sludge from Diesel Bug?... it could be asphaltenes that have agglomerated and fallen to the bottom as an oily tar like sludge, or it could be diesel oxidizing and degrading creating globules of dark sludge.
Stabilizers have a place and can help prevent oxidation, Dispersants can guard against asphaltenes and detergents protect the fuel components, essential in modern common rail engines. A good additive package should contain only those chemicals required given the duty cycle of the engine and it's geographic position. Our DieselAid® LDB for example contains Lubricity, Detergent and a Biocide and is formulated for fishing vessels and work boats operating in the ECA (see below) regions of Northern Europe. At 1 litre to 4000 litres of fuel, it is very economic.
Manufacturers are encouraged, (not always required) to treat fuel with stabilizers and lubricity improvers etc. Responsible ones do and some not so responsible, don't. After all, additives are a cost to the manufacture so it's plain they will only put the very minimum in.
A word about water
As discussed additives have a place in modern diesel giving clear benefits. However a lot of these benefits will be quickly reduced if water is allowed to build up. Water in the bottom of a diesel tank is by far the single greatest contaminant you will find and will quickly lead to many problems.
Water accelerates the degradation of diesel, it forms a habitat for Diesel Bug, it reduces the lubricity in the fuel, it helps the agglomeration of asphaltenes, rusts the tanks and fuel system and in extreme cases when absorbed in the fuel can turn to super heated steam and blow the top of the fuel injectors!
Clearly then water it is not good but it is very easily removed by regularly opening the drain valve. For those tanks that don't have a drain valve we recommend fitting a Diesel Dipper®. This simple bypass system sucks from the floor of the tank and ensure all water and sludge is sucked up so it can be drained off.
If you bunker regularly in the Emission Controls Area’s (ECA), then a lubricity and deposit control additive should be used. Modern diesel in an ECA needs a lubricity additive which should be added by the supplier, most add the minimum, some don’t, so adding your own ensures the fuel system is protected. Additionally, modern diesel suffers greater system deposits referred to as IDID (Internal Diesel Injector Deposits) so needs to have a detergent added, even more so modern common rail engines.
Snake Oil is Still Out There Folks
The claims still persist however, during a recent exhibition I was presented with a product that would save 10% on fuel costs. To summarize fuel additives will not improve your fuel consumption although a cetane improve may give marginal benefits. What they will do is prevent the increase in fuel consumption from fouled fuel components and will certainly help prevent fuel system wear.
Contact us if we can help further or you have a particular fuel treatment requirement.