Should a diesel tank be kept full during lay-ups?

[hagrid]

I haven't read all the posts but will comment based on accumulated knowledge.

 

Keeping the tank topped up reduces the risk of condensation ( water) in the tank.

Modern diesel contains a % of bio diesel, more so in summer than winter.

Bio Diesel and water can encourage the growth of algae commonly known as diesel bug.

If diesel bug becomes established, it blocks fuel filters and is very difficult to eradicate.

 

My advise would be to ensure that your tank is filled after October, dose it with soltron or a similar anti bug treatment and keep it topped up during periods of lay up.

 

 

[Ducto]

Short one is yes; I would say.

 

Put some diesel bug in for long lay-ups. Yachties do this over wintering in the boatyard.

 

[QFour]

If you are laying it up then you should be worrying more about the brakes and tyres than the diesel. Commercial vehicles are not designed to be laid up for the winter. Put some warm clothes in and get out and use it.

[Colin Leake]

One of my neighbours who has a canal boat tells me that bugs in the tanks of canal boats causing a sludge in the tanks bottom is such a common problem that mobile specialist firms exist to pump out the tanks, clean the bottom out and refill with fresh treated diesel. He always uses a additive in his before the winter layup.

 

I use a petrol extender in my garden machines and generator over the winter.

 

Like others on here I take our motorhome out for a 40 or 50 mile round trip once a month. Gives us a nice day out somewhere.

[aandncaravan]

There are multiple considerations:

 

Modern Diesel fuel both deteriorates faster and promotes the formation of Diesel bug than did the fuel formulations of a couple of years ago.

The high Sulphur level, reduced in 2012 and again in 2015?, was allegedly very good at both keeping Diesel bug at bay and preventing Diesel from degrading.

Modern low Sulphur Diesel should be regarded as having a max 4 - 6 month life, maybe less?, without treatment.

 

So things have changed a lot in the last couple of years. We would suggest that, unless you have an old Van with a Steel fuel tank, that you keep the fuel level as low as practical when the van is not in use.

 

This ensures that when you do use it, a full tank of fresh fuel means that the degraded fuel is 'swamped' by the fresh reducing the risk of issues.

 

 

If you have an old vehicle with Steel Tank (probably 20 + years old?) then keep it topped up as high as possible to prevent the Tank rusting. You only need the tiniest particle of rust to lead to Injector problems.

However, this may give issues with degradation and Diesel Bug so an anti-Bug additive would be a very good idea.

 

I have noticed that the Petrol in my 'Classic' 1973 Motorbike, which hardly gets used, has almost no octane value by 4 months and is a jelly by 12 months.

Yet I can remember the days not that long ago (alright 20 years) when an old bike/car could pulled out of a very long slumber and fired up without any issues.

 

Many of the old Citroen vans that we used to specialise in that came to us after being static for a while needed a Petrol Tank Flush. The Diesel vans often had a Tar like substance lining the tank that looked like someone had been trying to run it on Bitumen.

I took a lot of convincing it was the by-product of Diesel Bug. It was such a hard Tar like substance I found it hard to believe it could be produced by an Algae or whatever the 'Bug' is.

 

 

 

 

 

 

[Noody]

This thread has made me smile, culminating in a giggle considering the final post.

 

Over the years I've been fed with all sorts of information that ended up being nonsense so being a cynic at the age of 75 has to be respected by at the very least anyone over 50.

 

For example, the service interval on my golf is 20.000 miles regardless of the time it takes to get there so why is an annual oil change always recommended particularly if you use quality oil ?

 

 

[Derek Uzzell]

My experience is that the only people who believe that credibility increases with advancing age are the old codgers themselves. ;-)

 

As an aside, a French motorhome magazine article discussing Euro 6 motors stated that AdBlue begins to deteriorate at 6-months age and becomes ineffective after 12 months. Consequently it was recommended that motorcaravanners (who generally cover a quite low annual mileage) should not 'top up' their motorhome’s AdBlue tank (if it has one), instead refilling the tank when it approaches empty.

 

[aandncaravan]

Noody - 2016-10-15 7:47 AM

 

This thread has made me smile, culminating in a giggle considering the final post.

 

Over the years I've been fed with all sorts of information that ended up being nonsense so being a cynic at the age of 75 has to be respected by at the very least anyone over 50.

 

For example, the service interval on my golf is 20.000 miles regardless of the time it takes to get there so why is an annual oil change always recommended particularly if you use quality oil ?

 

 

 

One reason is that Oil has a shelf life, it deteriorates with age. This is especially true of modern high performance Oils with a high Additive pack.

Condensation also becomes an issue, particularly if the vehicle is only used for low annual mileages. Water contamination of Oil is an engine killer. During 2105 and early 2016 we were sent around 30 engines to rebuild where the Oil had been contaminated with Water and pretty much every part from Camshaft to Crank were beyond restoration. Only part we could carry forward was the Block, everything else was scrap.

 

Another factor with 1970's Oil was that the Oil picked up the by-products of combustion holding them in suspension. Over time this new 'Chemical combination' could lead to a faster attack of certain metals especially in the presence of Water. This lead to advice in the Classic Vehicle arena that the Oil should be changed prior to hibernation. Not sure this is true with modern Oils.

 

 

[Noody]

Derek, I'm not even considering my credibility unless you take me into my skills area. Otherwise I'm all ears.

 

Back to this bother about engine oils being changed annually even with low mileage and VW choosing a 20.000 mile period regardless of age I asked the dealership why this is the case for the Golf yet we also own a Beatle with what I assumed was the same 2 litre turbo engine. The dealership answer was that the Golf had a different engine, no mention of oils quality. The Beatle service period is 10.000 miles or 12 months.

 

I think it's IN-credible, hopefully this drags me away from OCS. Old-Codger-Syndrome.

 

Last year for the first time after covering only 3000 miles I didn't change the oil, I always have long life oil for engine and have to date changed it annually, the bloke I bought the van from hadn't had the oil changed for 4 years because it had only done 4000 miles, he thought that was fine on the basis of advise and sharing with others so I'm now one of a few, or perhaps many but I always adhere to the cam belt period regardless of mileage.

 

A lot of motorhome owners feel pain at forking out for a cam belt service at 12 miles, the consequences of failure on this issue are well known but once again it's IN-credible.

 

 

[Wortho]

Our van is stored in a barn in Sweden for 8 months of the year and I opted to leave the fuel tank empty for the past few years due to the possibility of the fuel deteriorating and algae forming. We fill it up in spring when we return and so far no issues. It also has an adblue tank and I have tried to keep this empty as well due to the fact that adblue freezes at -11c and it can go below -20c where we store the van. We also have to ensure that all water is removed from tanks and the truma and pipes etc as we had frost damage the first year when water trapped in the taps froze.

[Tall_Mike]

I keep our Van full - although for different reasons.

 

My own view is that vans are made to be used, If the van doesn't sit around for months unused, then problems wont happen. The very longest our van sits for un driven is about 3 weeks, then even if it's a 20 mile trek down the motorway and back to keep everything free and properly warmed up. I think the van has a fuel filter to catch the rubbish and that's a serviceable item that gets changed.

 

- This keeps the fuel flowing through the engine and re-cycled. - I tend to run the van down to half full and then fill up, - partly it feels cheaper, (of course it isn't) although with 90 ltr tank a full fill up is a pretty pricy experience. I've had the panic before when touring that we will run out in some obscure corner on a Sunday and can do without the stress, so I start from full each time

 

There is the weight factor, you are lugging around maybe 90kg of fuel which isn't trivial.

 

Petrol certainly deteriorates, I've seen motorcycle fuel degenerate to a glue like substance which kills the carbs and causes all manner of mayhem..

 

Oil and certainly brake fluid is hydroscopic, so even though our van has a 2 yearly service schedule I have the oil changed with a recommended product and a new oil filter annually, I think Fiat themselves now recommend this in their service schedules for low usage vehicles. - Haven't had a problem so far following this regime.

[EJB]

Many thousands of Motorhomes spend months sitting in Dealers forecourts and don't seem to suffer.

 

We used to top up diesels in winter but that was donkeys years ago before pressurised tanks and in countries where it actually got really cold! ;-)

[laimeduck]

There is another reason for keeping fuel tanks full - water condensation & rust inside the tank.

When I was learning to fly it was standard practice to fill the tanks at the end of the day to prevent this.

Each morning fuel was/is water tested by sampling the fuel drain off. The same applies today.

Same problem on sailing yachts which are in a very humid environment.

 

If a steel tank is left empty for a long period, rust can form which can then flake off.

 

Not a problem for most vehicles of course as they are used reasonably regularly, but the OP's isn't.

It it were mine I would leave it brimmed.

 

 

 

[monique.hubrechtsgm]

Missing here is prove from the oil companies. All tanks have sludge in the bottom , and water. The same you have in your crankcase of your ducato. If their crankcase ventilation does not work. These two are bad for the injectors, intercooler. turbo oil etc.

[Keithl]

laimeduck - 2019-01-08 3:57 PM

 

There is another reason for keeping fuel tanks full - water condensation & rust inside the tank.

 

 

And may I ask when did you last see a steel tank used on a motor vehicle?

 

I don't think many, or even possibly any, have for probably the last twenty five years!

 

Keith.

[laimeduck]

 

 

 

And may I ask when did you last see a steel tank used on a motor vehicle?

 

I don't think many, or even possibly any, have for probably the last twenty five years!

 

Keith.

 

You may ask Keith and I expect you are right except maybe for my Citroen 2CV but then she is very old!

[monique.hubrechtsgm]

In the ducato fuel filter there is a electric contact about water, and a drain valve. Have anyone had this alert on the dash? How much water came out? Be aware that your tank station can pump it it in. Pump the jam. *-)

[Wortho]

Fuel contamination is a concern and the modern diesels seem to tolerate it less with the higher fuel pressures and tighter tolerances. I have been following a thread here in Oz where some posters have had major engine troubles from contaminated fuel usually caused by water ingress in the service station tanks. One poor fellow had to replace his entire motor at a cost exceeding $20,000. Its worth checking with your insurer if you are covered for damage caused by contaminated fuel as it appears not all of them do. You would hope that the fuel companies would reimburse you if you could prove the fuel came from them but not always the case it seems. Choice magazine did an article on this issue....https://www.choice.com.au/transport/cars/maintenance/articles/petrol-stations-selling-contaminated-fuel-customers-with-repair-bills

[DickB]

During my 40 years of sailing the composition of diesel changed dramatically with serious consequences for both the tank and engine. For the last 10 years the EU has directed an ever increasing percentage of bio in fuels; it is now up to 10%. Apart from causing deforestation in Malaysia and Indonesia so that oil palm plantations replace prime forest, the bio attracts water which then causes diesel bug. This slime can completely block filters and injectors. In addition to the addition of bio which definitely degrades seals in older engines, today's diesel has much reduced sulphur which is a powerful lubricant of fuel injection components.

 

To prevent water absorption over the long winter layup tanks are always filled to the brim AND a biocide treatment is added. The additive compensates for the reduced lubricity of low sulphur, maintains the octane value, and it breaks down the water so it is soluble in the fuel and passes through the pump and injectors. There are numerous treatments available, but Marine 16 is highly regarded (used by RNLI). I never had problems afloat so I follow the same procedure with my motorhome.