Is Fuel Polishing Snake Oil?

Mark Maulden · Sep 12, 2012

For that price, they polished, put an access plate in the tank, cleaned the tank, and put access plates in both water tanks....That was the very first thing I did when I bought the boat. If you're worried about the tank, then punch a hole in it and clean it. Check your fuel pickup tube while you're at it.

Steve Dion · Sep 12, 2012

I could not agree more with Mark.

Is your engine not running properly.

Don S/V ILLusion · Sep 12, 2012

If your tank has baffles, ask them how they manage to sheer the crap off the walls when they can't possibly reach behind them with any force.

alexco38 · Sep 12, 2012

For A lot less than $250 I put my own polishing system in. just a pump, a filter, a valve and some fuel hoses.

Occasionally open up the access port and pressure wash the inside, of cause remove all the fuel first. You must save the water for dispose properly.

Fuel polishing is not snake oil, But $250 may be too much.

zeehag · Sep 12, 2012

in sd, in 2002, polishing fuel was 300 dollars. that fee encouraged some friends of mine to install the filters and pumps in their boats and do their own polishing.

RichH · Sep 12, 2012

As one deeply involved in filtration engineering for almost 35 years .... recirculation polishing without FIRST cleaning out the tank IS snake oil ... and will only 'temporarily' --- say again TEMPORARILY clean the oil.

Recirculation polishing prevents the 'growth' of particles into larger and large size, and removes the 'seed particles' (mostly bio-forms) from the fluid. The constant removal exponentially decreases (and removes) the amount of particles.

If you dont periodically inspect and clean the tank walls, those particles 'stuck and growing' (growing fungal filaments, etc. and agglomerating sticky gel-like particles) only become the seed particles for new and larger particle 'growth' ... AND when the matt-like 'colony' of living particles break loose (because of dead and dying micro-organisms) they rapidly 'slug' the previously cleaned up oil with an exponential amount of even more particles.
Recirculation polishing removes the particles before they can affix to the walls; but, it cant remove those particles from the walls if they have formed a 'sticky colony' (calcyx).

Recirculation polishing of a fouled tank is of NO long term benefit. You HAVE to start with a CLEAN(ED) tank.

---------------------------------------------------
FWIW -
•DONT keep your tank full or 'topped off' if you arent going to use is SOON. Fuel oil exposed to the atmosphere (through the VENT) DEGRADES and becomes INFECTED.
•Water that enters the tank vent will only SATURATE the amount of oil present, less amount of oil = less total amount of water.
•Tanks do NOT 'condensate' all by themselves; if that were true we wouldnt need water wells, just empty tanks that magically fill with water ... and you know that doesnt happen. The dry oil from the refinery transfers the water from the atmosphere into the oil until physical/chemical equilibrium saturates the oil; the less oil, the less total amount of saturation.
•Even if the oil does become contaminated, a smaller amount that is burned is quickly burned. A large amount of contaminant doesnt burn very well and can pass right through the combustion chambers as 'incompletely burned' and can then easily 'coke' on the hot internal walls of the exhaust manifold and injection elbow.
•The typical 'racor' only has about 30 GRAMS (~1 ounce !!!!) of 'dirt capacity'
•Dont 'top-off' the tank unless you will SOON use the entire amount. Drain/empty the tank for long term storage - burn the oil in your oil-burner at home.
• The modern liquid 'tank cleaners' are of value ... but youre going to need a lot of tank cleaner and filters if the tank is 'crudded'. (I use a minimum amount of tank cleaner in my clean tank with permanently installed recirc. filters --- helps keep the tank walls 'cleaner'.)
•(if your tank is prone to serious and frequent contamination, consider to put a bio-blocking ~0.45µM or less, 100%/'absolute' removal efficiency rated FILTER on the vent line. Funguses spread by distribution of airborne 'spores')

The 'proper' way to recirculation polish is to FIRST: clean the tank. Then continuous recirculation polishing will 'help' keep the tank clean and relatively free of particulate.
Other have stated, that if the tank has baffles, etc. .... there is no way in hell that the relatively LOW amounts of low pressure, low velocity recirculation fluid will affect 'knocking loose' the particles from the walls! ... nothing beats a long handled scrub brush and few pounds of paper towels (burn them when finished!) ... then chemical tank cleaner, then recirculation polishing a small amount before you put in new/fresh fuel.

Is your fuel or tank contaminated? ... how to tell:
draw out a small (4 oz.) sample of the oil and put into a CLEAR glass container and hold it between your eyeball and STRONG white light. If there is any HAZE noted in the oil, its contaminated and the tank should be inspected for heavy wall deposits ... and if 'sludge' is noted on the walls, then mechanically CLEAN IT OUT; ....... and then, recirculation polished! Uncontaminated fuel oil is "crystal clear" when held up to strong white light.
Sadly, most fuel oil from 'marinas' that only less than occasionally get their tanks filled .... usually the oil already has a 'haze'. Check the oil before it goes into YOUR tank, if 'hazy' find a 'high turnover source (truckstop, etc.) that sells 'fresh' oil.

;-)

RichH · Sep 12, 2012

Ill try to make this simpler, then.

Periodic maintenance recirculation polishing is of no probable benefit - because it cannot clean the walls, only the already loose particles or particles already in the oil.
The bulk of the particles come loose from the deposits of particles stuck to or 'growing' on the walls.

Inspection of the tank internals and followed up if needed by mechanical scrubbing or pressure washing of the tank internals is exponentially better than blindly recirc. polishing.

Recirc. polishing without prior cleaning is a waste of time and money, as its only a very temporary solution.
You could to achieve the exact same effects and with less expense and time by running the tank to near empty, remove or pump out and dispose of the remaining old oil and simply 'slosh in' a small amount of new oil to rinse and then pump this out too .... and then finally replace with new; but, the walls will still may be cruddy.

What Im really saying is that youve got to get inside the tank and LOOK at whats going on. Dont do that and all is a 'EMPTY GUESS'.

leftbrainstuff · Sep 13, 2012

RichH said:
As one deeply involved in filtration engineering for almost 35 years .... recirculation polishing without FIRST cleaning out the tank IS snake oil ... and will only 'temporarily' --- say again TEMPORARILY clean the oil.

Recirculation polishing prevents the 'growth' of particles into larger and large size, and removes the 'seed particles' (mostly bio-forms) from the fluid. The constant removal exponentially decreases (and removes) the amount of particles.

If you dont periodically inspect and clean the tank walls, those particles 'stuck and growing' (growing fungal filaments, etc. and agglomerating sticky gel-like particles) only become the seed particles for new and larger particle 'growth' ... AND when the matt-like 'colony' of living particles break loose (because of dead and dying micro-organisms) they rapidly 'slug' the previously cleaned up oil with an exponential amount of even more particles.
Recirculation polishing removes the particles before they can affix to the walls; but, it cant remove those particles from the walls if they have formed a 'sticky colony' (calcyx).

Recirculation polishing of a fouled tank is of NO long term benefit. You HAVE to start with a CLEAN(ED) tank.

---------------------------------------------------
FWIW -
•DONT keep your tank full or 'topped off' if you arent going to use is SOON. Fuel oil exposed to the atmosphere (through the VENT) DEGRADES and becomes INFECTED.
•Water that enters the tank vent will only SATURATE the amount of oil present, less amount of oil = less total amount of water.
•Tanks do NOT 'condensate' all by themselves; if that were true we wouldnt need water wells, just empty tanks that magically fill with water ... and you know that doesnt happen. The dry oil from the refinery transfers the water from the atmosphere into the oil until physical/chemical equilibrium saturates the oil; the less oil, the less total amount of saturation.
•Even if the oil does become contaminated, a smaller amount that is burned is quickly burned. A large amount of contaminant doesnt burn very well and can pass right through the combustion chambers as 'incompletely burned' and can then easily 'coke' on the hot internal walls of the exhaust manifold and injection elbow.
•The typical 'racor' only has about 30 GRAMS (~1 ounce !!!!) of 'dirt capacity'
•Dont 'top-off' the tank unless you will SOON use the entire amount. Drain/empty the tank for long term storage - burn the oil in your oil-burner at home.
• The modern liquid 'tank cleaners' are of value ... but youre going to need a lot of tank cleaner and filters if the tank is 'crudded'. (I use a minimum amount of tank cleaner in my clean tank with permanently installed recirc. filters --- helps keep the tank walls 'cleaner'.)
•(if your tank is prone to serious and frequent contamination, consider to put a bio-blocking ~0.45µM or less, 100%/'absolute' removal efficiency rated FILTER on the vent line. Funguses spread by distribution of airborne 'spores')

The 'proper' way to recirculation polish is to FIRST: clean the tank. Then continuous recirculation polishing will 'help' keep the tank clean and relatively free of particulate.
Other have stated, that if the tank has baffles, etc. .... there is no way in hell that the relatively LOW amounts of low pressure, low velocity recirculation fluid will affect 'knocking loose' the particles from the walls! ... nothing beats a long handled scrub brush and few pounds of paper towels (burn them when finished!) ... then chemical tank cleaner, then recirculation polishing a small amount before you put in new/fresh fuel.

Is your fuel or tank contaminated? ... how to tell:
draw out a small (4 oz.) sample of the oil and put into a CLEAR glass container and hold it between your eyeball and STRONG white light. If there is any HAZE noted in the oil, its contaminated and the tank should be inspected for heavy wall deposits ... and if 'sludge' is noted on the walls, then mechanically CLEAN IT OUT; ....... and then, recirculation polished! Uncontaminated fuel oil is "crystal clear" when held up to strong white light.
Sadly, most fuel oil from 'marinas' that only less than occasionally get their tanks filled .... usually the oil already has a 'haze'. Check the oil before it goes into YOUR tank, if 'hazy' find a 'high turnover source (truckstop, etc.) that sells 'fresh' oil.

;-)

+1

kloudie1 · Sep 13, 2012

Agree.. Another point is that the diesel at the refinery and at distribution terminals is stored in large tanks that frequently have holes in the roofs where rain gets in. There is normally a water "heel" in the tank bottom. The diesel that is delivered to the retailers is normally almost saturated with water when you put it in your tank.. Good idea to use a Baja filter funnel when fueling to catch any free water that ya might be adding otherwise. A preventive maintenance item !

weinie · Sep 13, 2012

RichH said:
Ill try to make this simpler, then.

Periodic maintenance recirculation polishing is of no probable benefit - because it cannot clean the walls, only the already loose particles or particles already in the oil.
The bulk of the particles come loose from the deposits of particles stuck to or 'growing' on the walls.

Inspection of the tank internals and followed up if needed by mechanical scrubbing or pressure washing of the tank internals is exponentially better than blindly recirc. polishing.

Recirc. polishing without prior cleaning is a waste of time and money, as its only a very temporary solution.
You could to achieve the exact same effects and with less expense and time by running the tank to near empty, remove or pump out and dispose of the remaining old oil and simply 'slosh in' a small amount of new oil to rinse and then pump this out too .... and then finally replace with new; but, the walls will still may be cruddy.

What Im really saying is that youve got to get inside the tank and LOOK at whats going on. Dont do that and all is a 'EMPTY GUESS'.

Rich,
Im sure its been covered to death before, but what is your take on biocides and fuel stabilizers?

TDudley · Sep 13, 2012

This is interesting. I have a 31 year old boat and I would be willing to bet that the tank has never been cleaned due to access issues. I plan on resolving that. My question is do the primary and secondary fuel filters I have solve any issues with the fuel. I have owned her for 4 years with no apparent problems.

xcyz · Sep 13, 2012

kloudie1 said:
Another point is that the diesel at the refinery and at distribution terminals is stored in large tanks that frequently have holes in the roofs where rain gets in. "-snipped-" The diesel that is delivered to the retailers is normally almost saturated with water when you put it in your tank..

Strongly Disagree!:naughty:

RichH · Sep 13, 2012

weinie said:
Rich,
Im sure its been covered to death before, but what is your take on biocides and fuel stabilizers?

All good! ... also chemical tank cleaners, too.

RichH · Sep 13, 2012

TDudley said:
This is interesting. I have a 31 year old boat and I would be willing to bet that the tank has never been cleaned due to access issues. I plan on resolving that. My question is do the primary and secondary fuel filters I have solve any issues with the fuel. I have owned her for 4 years with no apparent problems.

Every storage/tank, etc. has its individual fouling characteristics. Some become rapidly fouled, some dont at all. The only way to tell is to 'get inside and look' ... otherwise its totally a crap shoot and that includes huge and constant change out of fuel delivery filters ... after the boat goes through a heavy seastate.
The fuel delivery (Racor, etc.) filters are there to do a job and if they get plugged up they did their job in getting overwhelmed by 'crud'. However if there is no particle challenge to the filters, they still do their job.
The simple solution to all this --- get inside the tank and look at the condition of the walls and bottom for the accumulation of 'crud'. Then decide if or not any 'tank maintenance' is needed.

Warren Milberg · Sep 13, 2012

Polishing fuel in the relatively small tanks most sailboats have, without a prior cleaning of the interior of the tank, is like polishing a turd: you get a nice shiny turd. You are far better off in spending money and/or effort to clean your tank, properfly dispose of old circumspect fuel, and put new/fresh fuel in.

heritage · Sep 13, 2012

•DONT keep your tank full or 'topped off' if you arent going to use is SOON.

I have always read the opposite: Fill the tank before long term storage. This is also preached to RV owners that store their rigs over the winter. Here is what Don Casey suggests concerning fuel tanks in an article in Boat US: http://www.boatus.com/boattech/casey/fuel-system-maintenance.asp

What you are saying makes sense, but it flies in the face of what I considered to be the prudent way to leave the boat for long term storage. I consider condensation in a large metal tank in Florida to be a major generator of water, and the more space for air in the tank, the greater the amount of water condensed. When that water has totally saturated the fuel, then it settles to the bottom of the tank.

Maybe MaineSail can run some tests for us to help us decide the best approach.

RichH · Sep 13, 2012

This issue is very simple.
The more the mass amount of oil, etc. stores energy in the form of heat. With temperature changes it takes longer for the mass of oil to 'expel' its amount of heat back to the atmosphere by the process of thermal equilibrium, the reverse is also correct when the mass of oil is 'cold' ... less mass of oil and the thermal recovery to atmospheric temperatures is FAST, filled with oil the thermal differences 'lag'. The residual amount of oil is 'storing' the amount of heat, and by thermal transfer being quite inefficient without 'moving' fluid coming in contact with the tank walls ... creates the termal differences which enhance 'condensation'.
There by simple logic it stands that less mass of oil stored provides less 'thermal swing' which enhances 'condensation'.
Enhanced condensation provides the drive for the water that saturates into the oil to further 'drop out' due to gravity settling, and then forms a separate zone of free water 'under' the oil .... and the mass of water now stored in the bottom also enhances the delay of thermal swing.

Just ask yourself the question ... can an *empty tank do this?
Do empty tanks fill with condensate water?

The answer is obvious, they do not. The reason that water condensates in the tank filled with oil is that the water .... has totally saturated the oil, first and before the vapor pressure of the water allows it to 'condensate' on the cold walls, and then settles quickly through oil to the bottom of the tank where it becomes isolated from the water saturated oil but still available to keep the water saturation of the oil going.

An empty (small) tank doesnt readily 'condensate' water ... theres not enough mass to affect the mass transfer of water into the oil ... simply because there is NO OIL! ;-)