Fuel "sloshing"

[Alpha2110]

You have to be a moron to overfill the skoda filler, the gun will bum out again and again, before you even get close to the fuel up to the cap. You cant technicaly over fill it anyway, look at pictures of the tank, the filler is lower than the top of the tank, this is the expansion void,  aproximatly 2 to 4 percent of the volume of the tank.

 

Dont get confused with lorry drivers over filling there tanks, there are a different designs, and the latest ones on vehicals have the same expantion void. 

 

The sloshing has nothing to do with an expantion tank or void, its fuel sloshing around the tank from full to 3/4 full. Its the shape of the tank and baffle design, if it has any. 

 

Some older cars had dedicated reserve tanks but its just terminology now, it usualy means the quantity of fuel left in the main tank when the warning light comes on. 

[Gerrycan]

Petrol/diesel as liquids are effectively incompressible but their volume does increase with temperature so fuel tanks are designed to have an 'expansion zone' which is occupied by air which of course is compressible.

The expansion zone safely caters for any liquid volume increase due to temperature rises. Some parts of the world it is possible to experience diurnal variations that exceed 40 deg C. so all manufacturers who sell their vehicles worldwide have to cater for this possibility.

 

This is an old thread resurrected by a complainant who has just bought an early model Octavia and there are now some comments being added to say they do not experience the sloshing. I assume the latter are owners of relatively new cars and the issue may well have been quietly addressed by Skoda, which is their privilege (in the fine print of all brochures).

I'd be pessimistic that he will get satisfaction at the dealers.

 

The separate charcoal canister is a legal requirement (in most countries) to capture fuel fumes when the car is not in use and then feed the fumes back to the engine when it is started. I don't know if it is actually possible to fill the tank to a point where it floods the charcoal canister but obviously that would not be a good thing and may well be expensive to replace.

Diesel is far less volatile than petrol with much lower evaporation rates so I am not certain whether they are equipped with a charcoal canister.

 

Fuel tank size has been the subject of many threads, mainly because many diesel owners complained that when they were prompted to refill (low fuel gauge reading, red light and even maxidot prompts) then they could only get 42 litres or less in.

Again, this is not something being reported by owners of new Octavia so this may also have been addressed by Skoda at sometime.

The official 50 litre capacity is nominal and there have been other (petrol) owners who have got as much as 55 litres into their tank, although they must of ignored the warnings for some time, which is either courageous, or stupid if you run out of fuel on the highway

 

There is always some risk of encountering design flaws for early adopters of a new model, or for those that buy those early models second hand.

 

Fuel additives? Like religion, you are either a believer or you are not, certainly some of the product claims require more than a little faith.

Personally I just stick to the basics and try to put in the recommended fuel from a reputable source with good turnover.

 

 

Edited 2 March, 2017 by Gerrycan

[automass]

19 hours ago, Warrior193 said:

 

 

Thanks to everybody for the advice..I have learnt a lot, but could someone tell me how can I get the fuel out of the expansion tank to stop hearing sloshing.

[langers2k]

10 minutes ago, automass said:

 

Thanks to everybody for the advice..I have learnt a lot, but could someone tell me how can I get the fuel out of the expansion tank to stop hearing sloshing.

 

If you have got any fuel in the expansion space, it will come out as soon as the fuel level drops.

[SWBoy]

15 hours ago, automass said:

Now my point is how can i make the expansion tank empty and stop hearing this Sloshing?

 

16 hours ago, langers2k said:

Every car has space to allow the fuel to expand, this is generally called an expansion tank even if it's not a separate tank. By filling the expansion space with fuel you might find that you spill diesel on the road, if the fuel warms up and expands, you might leak diesel or possibly even damage seals in the fuel tank if the pressure can't escape. The expansion space is there for a reason so it's probably best not to fill it with fuel.

 

[Breezy_Pete]

The expansion area is created by the fact that the filler pipe goes into the side of the tank, part way up, rather than into the top. As you fill the tank, air can escape back up the filler pipe but only until the internal level reaches the top level of the incoming pipe. After  that, as the vent valve is closed, the air/vapour above the fuel is trapped and will compress slightly as you add more fuel into the filler neck.  Once the force of this compression balances the weight of the fuel in the vertical bit of the filler pipe, no more fuel will go into the tank (unless the air/vapour is released by opening the vent valve.

 

Super simple diagram showing the fuel level at which the expansion volume starts to compress:

 

 

 

[automass]

Thanks for explaining it nicely..is there any link related with your explanation!

 

Other thing is  why in different car people do not hear sloshing after over filling them..like my friend told me that he always over fill his mercedes, but never come across of listening sloshing noise.

[Ootohere]

Some people are Mutt & Jeff, some have different hearing and that is normal,

and some expect noises from vehicles & just drive and listen to the radio, passengers etc.

 

Some wear glasses or lenses, and some have poor vision but wear none.  Its a human type thing, people see and hear different things 

and lots of Workshop Technicians are called 'Tommy'.

[automass]

Just to update the post...I am about to get my car today (the car was with cargiant to diagnose about fuel sloshing, poor MPG, fuel filler lock, rattling noise and Hill Hold Assist being not working). All the problems were dealt with and apparently what they are saying about fuel sloshing is common a characteristic for this car. they compared my car with same another one and found similar sloshing noise. If i am not happy with their finding i can take my car to local skoda delaer and pay them diagnostic, get the report and get back to cargiant if anything else needed attention.

About fuel filler neck: its normal. Fuel filler is not meant to open with any kind of Funnel for the latest car so that people can not contaminate diesel with petrol. I have to have a fuel filler funnel adapter to open it which seems to be no where found. (very weird)

Poor MPG: Changed some parts. (Fuel filter, Fuel Pressure Release valve)

 

[Ootohere]

?

You have seen the posts where some hear sloshing and some do not, so what is a Skoda Dealer to check?

 

As to the filler neck being normal, was there anyone doubting that?

The diesel gun at a filling station pump goes in so that you can put in diesel, and you get funnels so you can fill from cans or put in additives, 

easy enough to source.

Internet / search engines / google is your friend.

 

Maybe time to see what actual MPG / efficiency you can get on journeys.

[automass]

But it shouldn't be the case that some people can hear the noise and some people can't with exact same car. It appears to me that all cars do it, just some people do not pay attention to it. If cargiant said that they compared the car with another same one which makes sloshing noise, what can I say!

I bought a Lucas injector cleaner additive from the fuel station and guy said I have to push and pour it in the fuel tank and normally all the other people do it this way..but when I did it the lock didn't open and all the liquid was just wasted. Are all the Octavia MK3 owners having same fuel locking mechanism or it just me the different. 

[Ootohere]

It is a pity you could not have run a tank or 2 of diesel and seen what mileage you get from that fuel and if there was an improvement before adding additives, 

then seeing if any difference.

 

I hope all is well now and you get the MPG you were hoping for.

[automass]

Hi,

About Fuel sloshing noise...I have filled the tank and stopped when auto Cut Off cut off..now I can not hear any more fuel sloshing noise..thanks God for that..

[Arjun75]

I have noticed this from the day i bought the car.Happens only when the fuel tank is full. In my experience it  gradually reduces and disappears as it apporaches 3/4 th.

[OctaviaItalia]

It is some what annoying and a few months in still makes me jump when I brake and hear the sloshy bump from the rear.

[Gerrycan]

Well the common factor amongst the complainants is that they are fairly early model Octavia.

This is an old thread that has been resurrected by someone who has bought a second hand early model mk3 and the newer comments are also from early model owners.

 

So perhaps the solution is to just buy a newer model?

[automass]

I think as other people told here that overfilling the tank makes fuel go to expension tank where it makes the sound..so if people can finish the fuel from main tank and then expension tank's fuel will come out..and never overfill again..that's what I did.

[tigermad]

7 minutes ago, automass said:

I think as other people told here that overfilling the tank makes fuel go to expension tank where it makes the sound..so if people can finish the fuel from main tank and then expension tank's fuel will come out..and never overfill again..that's what I did.

I thought it was confirmed there is no expansion tank?

 

this is what you said:

I have just spoken to SKODA awhile ago..and they said that their is no EXPANSION TANK or such for the fuel for octavia. So whoever is saying fuel goes in EXPANSION TANK by carry on filling after the auto cut off is hypothesis.

The man said filling must be stopped after auto cut off. if someone carries on filling then fuel can go to CARBON FILTER or CHARCOAL FILTER. I don't know what they are..but guy said its very dangerous and need replacing those parts if it is the case.  

So whoever hears this sound may be in some point overfilled the tank which made carbon filter to fill with fuel. LISTENING SLOSHING NOISE FROM THE FUEL TANK IS NOT NORMAL OR IT'S NOT A FEATURE, THAT'S WHAT MY POINT.

Edited 16 March, 2017 by tigermad

[Gerrycan]

1 minute ago, automass said:

I think as other people told here that overfilling the tank makes fuel go to expension tank where it makes the sound..so if people can finish the fuel from main tank and then expension tank's fuel will come out..and never overfill again..that's what I did.

There is no 'other expansion tank', there is only an expansion area in the main tank. You are probably filling above the baffles and the fuel sloshes against the top of the tank. I expect Skoda just corrected this baffling problem.

 

By the way the first word in your signature's Latin quote should be "Non" not "None"

[automass]

That's eexactly what i wanted to mmean..someone in this thread posted a diagram which explains everything. Thanks Gerrycan for the correct explanation.

 

Really! I will fix it tonight when I'll be at computer. 

Edited 16 March, 2017 by automass

[Ferdinand01]

7 hours ago, Gerrycan said:

Well the common factor amongst the complainants is that they are fairly early model Octavia.

This is an old thread that has been resurrected by someone who has bought a second hand early model mk3 and the newer comments are also from early model owners.

 

So perhaps the solution is to just buy a newer model?

No....

I boght new MY17 2.0 CR and have this problem.

[automass]

15 minutes ago, Ferdinand01 said:

No....

I boght new MY17 2.0 CR and have this problem.

 

Don't overfill.. stop when automatically cut off cuts off.

[Gromle]

Never had any sloshing noises. 

But I never overfill, and mine being a 4x4 petrol its supposed to have a slightly different tank.

 

Or it might just be because scandinavian cars have additional insulation. Although I do not know where.

[toni8b]

On 3/16/2017 at 21:20, automass said:

 

Don't overfill.. stop when automatically cut off cuts off.

I always stop on first cut off and no help.

[bigjohn]

Two comments:-

• Re sloshing - My 2003 Superb I diesel always sloshed a bit after a 100 mile sor so for a while . My 2014 Superb II petrol doesn't do this . Possible to do with the density of the different fuels when slopping against the sides/top of the fuel tank
• Re overfilling - I used to brim my Superb I diesel but once when I had brimmed my petrol Superb II in Luxembourg (living in Yorkshire I can;t resist cheaper petrol) this triggered an engine management light after a while. I'd just bought the car so dropped into a German Skoda dealer. He didn't speak much English and I didn't speak much German, however the message was "Von click - Halte!!"