Winterising a diesel - Fuel

[alt]

We all know that diesel can turn to sludge and organisms can grow over prolonged periods of time in diesel, so whats the best method to go about winterising your diesel engine?

1) Someone told me to fill the tank up to the top and put in some of that stuff that stops the diesel from sludging. The problem here is what will happen the diesel in the fuel lines?

2) I could almost empty the tank, but this would risk picking up sludge

3) I could turn off the fuel valve, and run the engine until the fuel lines are almost dry, then drain the diesel filter. Then I could do step 1

What do you guys do?

[Richard B]

AFAIK diesel bug problems are associated with water content?

Most people with inboard tanks of any type (petrol or diesel) fill them to the brim to avoid condensation during the winter.

[Andy Gee]

Originally Posted by alt

We all know that diesel can turn to sludge and organisms can grow over prolonged periods of time in diesel, so whats the best method to go about winterising your diesel engine?

1) Someone told me to fill the tank up to the top and put in some of that stuff that stops the diesel from sludging. The problem here is what will happen the diesel in the fuel lines?

2) I could almost empty the tank, but this would risk picking up sludge

3) I could turn off the fuel valve, and run the engine until the fuel lines are almost dry, then drain the diesel filter. Then I could do step 1

What do you guys do?

Fill 'er to the brim , seriously we have some machines that dont get used for over 8 months and have never had a problem with the diesel sludging.............petrol on the other hand
Also drain the raw water side by pulling of a hose and make sure that your fresh water has plenty of Anti Freeze in it. Grease/Spray anything movable and disconnect batteries.
Andy

[alt]

Thanks guys, do you recommend these products that 'stop growth' within the diesel?

-Edit- Also, should I dry the fuel lines by turning off the fuel valve and running the engine dry... or should I not bother?

[Andy Gee]

Originally Posted by alt

Thanks guys, do you recommend these products that 'stop growth' within the diesel?

I have used only one, Soltron I think it was called. Has a bit of sludge in the filter of a boat I bought and couldnt get into the tanks to clean them so I tried it. It did work and there was a noticable difference in the bowl of the filters although I would still prefer to get into the tanks if I were to have to do it again.
I remember reading in one of the Irish fishing mags about something that was developed for fishing boats, some type of enzime (sp) that ate the bugs .
Andy

[bernithebiker]

Sludge is most likely due to bacterial growth, and the warmer it is the more they like it, but if it is cold, then 'sludge' could simply be the paraffins in the diesel crystallising at low temperatures.

All diesels have 3 cold properties;

Cloud point (the temp at which the diesel goes cloudy) is +5'C for UK summer diesel (road diesel that is), -5 winter
CFPP (cold filter plugging point - the temperature at which a test filter becomes blocked by paraffin crystals) 0'C for summer, -15 for winter
Pour point (the point at which a test sample can no longer be poured (very close to freezing point) = about -18 for winter

So if you shut down your diesel boat engine at the end of the summer, you risk developing paraffinic 'sludge' at below +5'C if you have summer diesel in it.

So to avoid this, try to fill up after end September, when petrol stations should all have the winter spec.

Now if you just use marine diesel, that may be a bit different, as I think the spec stays the same year round, and it almost certainly is not as good quality as road winter derv. So again, to avoid troubles, pay a bit extra and do your last fill up with road derv, not marine diesel. Or put in about 30% kerosene. (lighter than diesel, much better cold properties).

[Poly]

I have a better plan... ...send me the keys and I will keep your boat busy over the winter period for you to save you "winterising" her!

[alt]

Originally Posted by Polwart

I have a better plan... ...send me the keys and I will keep your boat busy over the winter period for you to save you "winterising" her!

Thanks for the advise guys, just remembered I have about 4,000 litres of Kerosene out the back, would you recommend a fill of that?

[bernithebiker]

No, don't use neat kerosene (you are quite right in saying that in the UK heating oil is kerosene, whereas everywhere else in Europe it is low grade diesel - part of the reason why it is so expensive in the UK, as it is competing with the Jet A1 for aircraft).

Neat kerosene does not have a high enough cetane number, and performance in a diesel engine will be poor. It's viscosity and density are also lighter, and it's flash point is dangerously low, (about 40'C - easily acheived in a hot engine bay).

But a blend of up to about 30% kero into diesel is fine, and will dramtically improve the cold properties of your fuel.

[Andy Gee]

Originally Posted by alt

Thanks for the advise guys, just remembered I have about 4,000 litres of Kerosene out the back, would you recommend a fill of that?

Nope, just fill the tanks and you'll have no probs, any waxing that MAY happen will be clear by spring . I would be more concerned about getting the right mix of Antifrezze in and all raw water out.
Andy

[alt]

Originally Posted by Andy Gee

Nope, just fill the tanks and you'll have no probs, any waxing that MAY happen will be clear by spring . I would be more concerned about getting the right mix of Antifrezze in and all raw water out.
Andy

I will drain the captive cooling system and re-fill with anti-freeze. I'll then do my best to drain the raw cooling system. I might be able to store her in a shed this winter (if im lucky) which would be great

[jwalker]

Get a 50/50 antifreeze mix through the raw water sytem after flushing it if you can. Leave it in to prevent corrosion.