The use of meths to remove water

[watcher]

Has anyone tried adding meths to their diesel to remove water?I used it several years ago on a petrol engine to good effect.The meths forms a solution with the water which then burns as normal in the engine,I just wondered if it would work in the same way in a diesel engine.

[mango]

Has anyone tried adding meths to their diesel to remove water?I used it several years ago on a petrol engine to good effect.The meths forms a solution with the water which then burns as normal in the engine,I just wondered if it would work in the same way in a diesel engine.

Welcome to this forum.

 

I am not sure how much meths would be needed to make water and diesel miscible, or what effect this could have on the engine.

 

I recommend leaning the boat over temporarily so that water collects at one side or in a corner of the fuel tank and pumping or siphoning it out.

[Phil Ambrose]

Hmm, water passing through the high pressure pump supplying the injectors may well have a detrimental effect on the pump which relies on the diesel to act as lubricant.

Phil

[forsberg]

Pumping out is always best.

There are a number of home cures but I prefer a proper additive like:

http://www.bellperformance.com/fuel-treatment/dfs-plus

Works fine if you follow instructions, you might want to replace/clean your filter repeatably after use.

There is a limit to how much an additive can remove so if it's really bad , back to pump out.

[blackrose]

Some of the diesel treatments claim to disperse the water or emulsify it into the fuel, but I wonder whether if it's a good idea to burn a water diesel-emulsion? It might be better to let it sit at the bottom of the tank and remove it at some point.

[Neil2]

It sort of works with petrol because meths is soluble in petrol but is meths soluble in diesel? I don't know.

 

I've heard of this but what I don't understand is how you get the meths to the bottom of the tank before it's all absorbed by the petrol. (or diesel) And I suspect you would probably have to use quite a lot of meths to absorb a small amount of water.

[Murflynn]

When I worked in Albania we were advised not to fill up our trucks at certain petrol (diesel) stations because it was common practice among some suppliers to water down their diesel, presumably aided by the use of emulsifying additives. I believe the same was true in Greece.

[rogeriko]

Diesel fuel attracts and absorbs water it is hydroscobic. Normal diesel contains about 0.02% water and when it absorbs more and more up to about 0.1% then the water starts to drop out into the bottom of the tank. When the fuel is warm, summer, it can hold double or triple the amount of water than in the winter. So in every 100 litres of fuel it is normal to have 1/10th litre dissolved water.

[Guest]

Diesel fuel attracts and absorbs water it is hydroscobic. Normal diesel contains about 0.02% water and when it absorbs more and more up to about 0.1% then the water starts to drop out into the bottom of the tank. When the fuel is warm, summer, it can hold double or triple the amount of water than in the winter. So in every 100 litres of fuel it is normal to have 1/10th litre dissolved water.

Thanks for that explanation. Often wondered where the drops of water at the tank bottom appear from.

[mango]

Having though more about this, I suspect that meths (methylated spirit) will contain water.

 

Alcohol, the main ingredient, usually contains about 5% water because that's what you get from distillation. There are ways of removing that water to produce 100% alcohol (absolute alcohol) but that costs money.

 

So drain off or pump out the water and use an additive to help make sure you never have diesel bug.

 

Boat builders need to design diesel tanks so that water collects in a corner or sump and can be drained off easily.

 

Owners should consider why the water gets into diesel tanks. It may be rain water, getting in through a faulty seal on a deck filler. A better arrangement would be to have a raised filling pipe with a cap. Water may get in through the fuel tank vent(s). I have seen water dripping off the rear rail onto a tank vent with the hole at the top. Condensation will introduce a bit of moisture but it is not going to be responsible for a pint of water at the bottom of the tank. The other possible reason is that the water is present in the fuel when it is purchased. Maybe the supplier is not careful about keeping the rain out of their storage tank and draining off any sitting at the bottom.

[mango]

Diesel fuel attracts and absorbs water it is hydroscobic. Normal diesel contains about 0.02% water and when it absorbs more and more up to about 0.1% then the water starts to drop out into the bottom of the tank. When the fuel is warm, summer, it can hold double or triple the amount of water than in the winter. So in every 100 litres of fuel it is normal to have 1/10th litre dissolved water.

Anyone who would like to look into this could try leaving a glass jar half filled with diesel standing for months or years in an unheated garage. I did this and the diesel remained clear for a couple of years. Compared with other materials, diesel fuel is not very hygroscopic. Unfortunately I cannot post a photo because I accidentally used the diesel to clean some engine parts.

 

The small amount of water that diesel normally contains is not a problem because it is so well dispersed that the fuel looks clear. Some of the diesel bug inhibitors (e.g. Fuel Set) work by ensuring that water is microscopically dispersed in diesel rather than collecting in drops. Diesel bug grows at the interface between diesel and water. Fortunately it does not seem to start unless there is visible water, or all our boats and cars would suffer from diesel bug.

[OldGoat]

I suspect that a considerable amount of denatured spirit (even if you could easily buy in such quantity) could achieve the result you need.

Methinks using one of the fuel additives that (claim to) emulsify the water) are available would be cheaper and more effective.

On that point the additives (IMHO) trap the water and turn it into a gel - which is removed -held- by the primary fuel filter (you do have one of course???).

I suspect the meths: holds the water in solution - which is not what you 'need'.

 

Just my thoughts....

[Murflynn]

Condensation will introduce a bit of moisture but it is not going to be responsible for a pint of water at the bottom of the tank.

are you sure?

imagine a half-empty tank going through hot/cold cycles on a typical day, say from 10C to 20C.

each cycle will draw in and expel a certain volume of fresh air (about 3% of the air content) each day through the vent.

so you may introduce 5 litres of moist air which will result in condensation when the steelwork cools in the evening.

multiply that be 365 days and you will see quite a lot of water running down the sides of the tank into the diesel.

my rough calculation suggest this could amount to 0.5 litres per year.

[cuthound]

 

Boat builders need to design diesel tanks so that water collects in a corner or sump and can be drained off easily

 

My boat has a shell built by Alexander Boatbuilders, and incorporates a drain point at the bottom of the starboard side. By standing on the starboard side of the engine to access the drain point I can remove all water from the tank.

 

Condensation can be a major source of water contamination, particularly if an above ground steel tank is left nearly empty over winter. When I worked for BT it was not unusual for the maintenance engineers to drain off up to 5% of a bulk tanks capacity per annum, if the tank had been allowed to get half full or less.

 

On our last share boat we had water in fuel issues when it was moored at a certain boatyard. We eventually found that they had never heard of draining their bulk tank and if they filled your boat when their tank was nearly empty they sold you several lites of water with your diesel.

[Tony Dunkley]

Has anyone tried adding meths to their diesel to remove water?I used it several years ago on a petrol engine to good effect.The meths forms a solution with the water which then burns as normal in the engine,I just wondered if it would work in the same way in a diesel engine.

No, it would be very harmful to the injection pump. You'd be better off draining the water out of the tank and drinking the meths.

[mango]

are you sure?

imagine a half-empty tank going through hot/cold cycles on a typical day, say from 10C to 20C.

each cycle will draw in and expel a certain volume of fresh air (about 3% of the air content) each day through the vent.

so you may introduce 5 litres of moist air which will result in condensation when the steelwork cools in the evening.

multiply that be 365 days and you will see quite a lot of water running down the sides of the tank into the diesel.

my rough calculation suggest this could amount to 0.5 litres per year.

Condensation will only occur when a surface is colder than the moisture-laden air. If the air is at the same temperature, damp air will enter and damp air will leave. That's purely based on the physics I learned at school, rather a long time ago.

 

I have not done a detailed study but on two occasions I have left a boat sitting with less than half a tank of diesel and found no significant water in the spring. It is obviously good practice to keep tanks full over winter to minimise the risk of condensation and perhaps to decrease rusting above the surface of the fuel.

 

I'm certainly not wanting to discount the effect of condensation, but feel that it's important to look at the possibility of rain water getting into tanks through deck fillers and vents, and the possibility of fuel containing water when purchased. I have had some that did and found out when filling up from cans.

 

It's also important not to put trust in a water trap. By the time that starts to do anything useful there could be an inch of water at the bottom of the fuel tank, depending on where the take of is positioned.

[Sabcat]

Our boat stood for a couple of years with the tanks about 1/3 full. I've got a dip tube that feeds the engine via filters and a water trap which was installed when the new engine was fitted and a tap to drain the tank from the bottom which used to be the fuel feed to the old engine (I had to fit a plug in it that can only be removed with tools to satisfy BSS). I drained the tank expecting to find water. There was none.

[Guest]

Having though more about this, I suspect that meths (methylated spirit) will contain water.

 

Alcohol, the main ingredient, usually contains about 5% water because that's what you get from distillation. There are ways of removing that water to produce 100% alcohol (absolute alcohol) but that costs money.

 

So drain off or pump out the water and use an additive to help make sure you never have diesel bug.

 

Boat builders need to design diesel tanks so that water collects in a corner or sump and can be drained off easily.

 

Owners should consider why the water gets into diesel tanks. It may be rain water, getting in through a faulty seal on a deck filler. A better arrangement would be to have a raised filling pipe with a cap. Water may get in through the fuel tank vent(s). I have seen water dripping off the rear rail onto a tank vent with the hole at the top. Condensation will introduce a bit of moisture but it is not going to be responsible for a pint of water at the bottom of the tank. The other possible reason is that the water is present in the fuel when it is purchased. Maybe the supplier is not careful about keeping the rain out of their storage tank and draining off any sitting at the bottom.

 

Having though more about this, I suspect that meths (methylated spirit) will contain water.

 

Alcohol, the main ingredient, usually contains about 5% water because that's what you get from distillation. There are ways of removing that water to produce 100% alcohol (absolute alcohol) but that costs money.

 

So drain off or pump out the water and use an additive to help make sure you never have diesel bug.

 

Boat builders need to design diesel tanks so that water collects in a corner or sump and can be drained off easily.

 

Owners should consider why the water gets into diesel tanks. It may be rain water, getting in through a faulty seal on a deck filler. A better arrangement would be to have a raised filling pipe with a cap. Water may get in through the fuel tank vent(s). I have seen water dripping off the rear rail onto a tank vent with the hole at the top. Condensation will introduce a bit of moisture but it is not going to be responsible for a pint of water at the bottom of the tank. The other possible reason is that the water is present in the fuel when it is purchased. Maybe the supplier is not careful about keeping the rain out of their storage tank and draining off any sitting at the bottom.

Indeed. I have been ridiculed before and stand by to be again, but I often change the rubber seal when I fill up on that stupid brass deck filler (seals were 3 for a quid last time, a few seconds to fit.) I much prefer a raised welded on pipe with a BSP threaded cap over it.

My brass filler seal once failed (unbeknown to me) and cause a breakdown and loads of problems afterwards. Complete PITA. 33p for a seal versus 50 quids worth of diesel and reliability is a no brainer in my world.

[carlt]

It seems a shame to waste a good sippin' meths on fuel tank maintenance when there are other products available.

[Emerald Fox]

Fox's solution: we got a little pump-thingy that gets attached to an electric drill. When we have 240v we can use the drill. There're 2 pipes attached to the pump - one we shove down to the bottom depths of the fuel tank, and the other pipe into 5 litre empty old see-through plastic water bottles.

 

Suck up 5, 10, 15 or 20 litres from the bottom. There's bound to be sludge & water in that lot.

 

You can let it settle out (6 hours? 12 hours?) and siphon the top portion back into the tank. Give the bottom stuff to whoever wants it.

 

Do this, say, twice a year? Does this make sense?

[Guest]

Fox's solution: we got a little pump-thingy that gets attached to an electric drill. When we have 240v we can use the drill. There're 2 pipes attached to the pump - one we shove down to the bottom depths of the fuel tank, and the other pipe into 5 litre empty old see-through plastic water bottles.

 

Suck up 5, 10, 15 or 20 litres from the bottom. There's bound to be sludge & water in that lot.

 

You can let it settle out (6 hours? 12 hours?) and siphon the top portion back into the tank. Give the bottom stuff to whoever wants it.

 

Do this, say, twice a year? Does this make sense?

We always do this in spring, then in autumn before the boat is laid up for three months. Always get a drop of water out.

We have a tube of stuff that you smear on the end of a stick and submerge in the tank . If any water is present, the stuff changes from a light brown to a red colour.

[mango]

It seems a shame to waste a good sippin' meths on fuel tank maintenance when there are other products available.

That's a thought. Would boaters need to declare what percentage of their meths they plan to use for propulsion, non-propulsion and drinking?

 

Indeed. I have been ridiculed before and stand by to be again, but I often change the rubber seal when I fill up on that stupid brass deck filler (seals were 3 for a quid last time, a few seconds to fit.) I much prefer a raised welded on pipe with a BSP threaded cap over it.

My brass filler seal once failed (unbeknown to me) and cause a breakdown and loads of problems afterwards. Complete PITA. 33p for a seal versus 50 quids worth of diesel and reliability is a no brainer in my world.

Hopefully those who build boats will learn about these problems. It's not uncommon to see covers over deck fillers and I know one person who has one over the tank vent.

[Mike Todd]

That's a thought. Would boaters need to declare what percentage of their meths they plan to use for propulsion, non-propulsion and drinking?

Hopefully those who build boats will learn about these problems. It's not uncommon to see covers over deck fillers and I know one person who has one over the tank vent.

Surprised no-one has mentioned the effect of biodiesel. It is widely reported that it is water-attracting in sufficient quantity to be a risk of diesel bug, unless action (such as additive or cleaing) taken to prevent it. It does not need to have rain co0me in - it goes in when the tank is re-fuelled.

[Guest]

Surprised no-one has mentioned the effect of biodiesel. It is widely reported that it is water-attracting in sufficient quantity to be a risk of diesel bug, unless action (such as additive or cleaing) taken to prevent it. It does not need to have rain co0me in - it goes in when the tank is re-fuelled.

Good point.I always put a dose of "Marine 16 Complete" in when I fill up.

That's a thought. Would boaters need to declare what percentage of their meths they plan to use for propulsion, non-propulsion and drinking?

Hopefully those who build boats will learn about these problems. It's not uncommon to see covers over deck fillers and I know one person who has one over the tank vent.

Yes I always cover the filler with a large plastic sheet when laid up, and an inverted cup over the breather (mine is on top of mooring dolly.)

[David Mack]

Condensation will only occur when a surface is colder than the moisture-laden air. If the air is at the same temperature, damp air will enter and damp air will leave.

Late in the day when it is getting cooler the air in the tank contracts, drawing in damp air from outside. As the temperature continued to fall, the ability of air to hold moisture decreases, and so while the absolute humidity in the tank is unchanged, the relative humidity increases to 100%. Any cooling beyond this point and the excess moisture precipitates out - in effect it rains in the tank. This is the same effect that puts dew on the ground (and on the boat).

 

The water sinks to the bottom, below the diesel and therefore (unlike the dew) cannot evaporate again as the tank warms up. And so there is a one way flow of water from the air to the bottom of the tank.

Edited February 3, 2015 by David Mack