Fuel Leak!

[Eric_DK]

Our car is a Skoda Fabia Estate with a 1.2 TSI engine. We bought the car here in Denmark as a brand new car from an authorized dealership on August 30, 1916
Last Friday, my wife and I were on our way home from an exhibition when we could smell petrol inside the car.The EPC control lamp lit up and a message about the Star-Stop system was malfunctioning appeared on the display. Since were almost at home, I drove cautiously the last few hundred metres to our driveway. 
Saturday, I tried to see if it was possible to find out where the leak was after checking all fluid levels, just in case. In our driveway covered with gravel, I couldn’t see any drops under the car or on the gravel. So, I moved tha car out on the tarmac road where a puddle appeared under the engine. Then I called the Danish equivalent of the auto club to have the car transported to my dealer’s garage. Today, the mechanic confirmed that our car is yet another of these defective models as described by earlier posters in this thread. He said the operation would cost a bit more than £900. 
Since we bought the car we have only driven a total of about 46,000 miles.

We have owned 4 Skodas since 1994 and never had similar problems.

Now, I wonder how many of these engines have failed or will fail?

Best regards,

 

Eric

 

[Mattheboy]

That certainty sounds familiar Eric, when mine went the same way I was told that it was a sheared bolt in the fuel rail if that helps. My Skoda Dealer paid 75% of the £550 bill through a "Goodwill Matrix" if that's helpful to you. My fabia was also a 2016 1.2 fsi that I got in the September.

 

Matt

[rum4mo]

@Eric-DK, have you ever considered reporting this fault to the motoring watchdog or road transport watchdog in your country, also any motoring organisation - for example we have RAC and AA in UK, just to see if they are interested in this problem.

 

I am currently trying to source "super strong stainless steel" bolts to replace the bolts holding the fuel rail on in my wife's August 2015 VW Polo, really trying to get in there and "improve" things before we have this dangerous failure occur with that car.

 

The bolts used by VW Group are stainless steel with a strength rating of 8.8,what I am trying to do is to replace them with stainless steel that is 10.9 strength, there is a company, I think they are Swedish called  Bumax or at least one of their fixings ranges are called Bumax and the bolts that I would like to get hold of are from the Bumax Ultra range, the only issue that I have is that I do not yet know is if this material while being stronger in tensile strength is also more or less suitable for use in this application, I have contacted their UK agents/seller but so far no reply!

[Eric_DK]

9 hours ago, rum4mo said:

@Eric-DK, have you ever considered reporting this fault to the motoring watchdog or road transport watchdog in your country, also any motoring organisation - for example we have RAC and AA in UK, just to see if they are interested in this problem.

 

I am currently trying to source "super strong stainless steel" bolts to replace the bolts holding the fuel rail on in my wife's August 2015 VW Polo, really trying to get in there and "improve" things before we have this dangerous failure occur with that car.

 

The bolts used by VW Group are stainless steel with a strength rating of 8.8,what I am trying to do is to replace them with stainless steel that is 10.9 strength, there is a company, I think they are Swedish called  Bumax or at least one of their fixings ranges are called Bumax and the bolts that I would like to get hold of are from the Bumax Ultra range, the only issue that I have is that I do not yet know is if this material while being stronger in tensile strength is also more or less suitable for use in this application, I have contacted their UK agents/seller but so far no reply!

@Mattheboy & @rum4mo

Thank you both for your responses. I will be calling the Danish Motorists Association in a few minutes when they open for business. I plan on trying to find out if there is a government agency that keeps track of such cases as well.

As far as bolt quality goes, somebody needs to take responsibility as it seems to be an error of some magnitude. I wonder where in Sweden the manufacturer is located. Also, even though the company is Swedish, the production could be outsourced to a country where quality control is not as good as in Sweden.
Now, I wonder if my mechanic has gotten better quality replacement parts. Maybe, I can contact the Swedish manufacturer directly, if you have their details.

 

Best regards,

 

Eric

 

[rum4mo]

What really annoys me about this failure is, this is a fixing failure, and not an assembly or other component failure, that should not be happening anywhere if that part has not been disturbed by a workshop or owner, also the fact that petrol under pressure then sprays out and down the front of a hot engine - okay the exhaust is on the rear of the engine, but with the car moving through air, the fuel will end up passing over the hot exhaust parts.

 

The VW Group part number for these bolts is :- N 105 464 03  and there are 4 of them,  they are M6 X1.0 X 16mm and have a cap head, the original ones have a spline or Torx female for tool fitting, but I'm trying to source cap head bolts with any type of  tool insert, probably hex, when one fails, they all should all get replaced and fuel  rail injector seals will also need to be replaced.

 

Edit:-  just stuff Bumax into Google and you should find them .

 

https://www.bumax-fasteners.com/bumax-grades/bumax-ultra/#:~:text=The strongest fastener on the market – and it is stainless&text=BUMAX® ULTRA also has,C with retained mechanical properties.

Edited 14 July, 2020 by rum4mo

[rum4mo]

Remember all I am trying to achieve, with my wife's car, is to improve its safety as I don't want this failure to happen to us, especially as I now know that it might - as it has happened to at least 7 others with this engine, also remember that Skoda build or did build all these 1.2TSI 16V petrol engines for all the VW Group marques, I'm sure if I talked to my VW dealership about this issue with my wife's 2015 VW Polo, my concerns would get dismissed as it is only (mainly) happening to Skoda cars and VW cars have VW built engines - that is not true, but that is what I'd expect to be told by VW dealership and VW UK!

 

Maybe to understand this a bit more, these engines feed their injectors from a common fuel rail and that fuel rail gets supplied from a cam shaft driven high pressure fuel pump.  The fuel rail is a steel tube that is rigidly fitted to the high pressure fuel pump at the LHS of engine, and then it attached to the cylinder head by 4 M6 stainless steel 8.8 strength along its length, 2 above the rail and 2 below the rail but all 4 spaced out along the rail's length. After the fuel rail passes the injector for cylinder number 1, it extends maybe 75mm and that length has no other support , that end of the fuel rail is open and a fuel pressure switch assembly is mounted or screwed into the end of the rail.  So, when you consider everything, the bolt that is nearest the RHS of the car is the one that will always fail first as it carries more load than any of the others, ie the most LHS bolt is closest to the high pressure fuel pump which must be stopping any tendency for that end of the fuel rail to move about due to injector pulsing etc.

 

Just my thoughts as far as I've worked  things out!

 

Note:- I'm not trying to sort things out completely, I'm just trying to apply a "sticking plaster", I think that the design of the fuel rail is wrong, and the only way to fix this issue properly, is to provide an extra "anchor" fixing at the "free" end of the fuel rail. ie brace it to the cylinder head and so remove the extra load that the bolt that snaps its head off is experiencing.

Edited 14 July, 2020 by rum4mo

[Breezy_Pete]

A bit of Loctite might be all that's required. Self-loosening due to vibration may be resulting in fatigue failure, once the parts become free to move relative to each other. An end-on view of both bits of @Lemto's broken bolt might shed more light on this, if still available.

 

 

[Lemto]

5 minutes ago, Wino said:

A bit of Loctite might be all that's required. Self-loosening due to vibration may be resulting in fatigue failure, once the parts become free to move relative to each other. An end-on view of both bits of @Lemto's broken bolt might shed more light on this, if still available.

 

 

Sorry to see there's been more people affected by a similar issue. It's important to be thankful that nobody has been hurt thusfar, hopefully never will. I unfortunately just have three images of the bolt and they aren't great. I can't remember if I posted these at the time but hopefully it helps.

 

I forgot to ask my mechanic which replacement he purchased and its probably too late now. But I do remember him saying it was probably due to them being drilled too tightly. 

[Breezy_Pete]

Thanks @Lemto; unfortunately, there's not much visible of the end surfaces. Some similarities with images on page 3 here though: https://www.asminternational.org/documents/10192/20564188/amp17208p18.pdf

Overtigthening would tend to cause necking of the threads near the failure point, as I understand it.

 

Perhaps @Eric_DK can request the broken parts from the place mending his car. In this country it is your legal right to be given such parts, if you request them back. Not sure if same will be true in Denmark.

 

[rum4mo]

1 hour ago, Wino said:

A bit of Loctite might be all that's required. Self-loosening due to vibration may be resulting in fatigue failure, once the parts become free to move relative to each other. An end-on view of both bits of @Lemto's broken bolt might shed more light on this, if still available.

 

 

 

No, normally nothing to do with slackening off, it is the head of the one nearest the RHS end that gets snapped off, if anything, these bolts need to be fitted into the alloy head with a bit of antigalling paste on them.

 

Without any recognition of this issue from VW Group, all people can do is replace with the correct 8.8 grade stainless steel bolt, or if I get any where with trying to source higher strength stainless steel bolts, replace with 10.9 or even higher special stainless steel bolts and hope to stay lucky.

[Breezy_Pete]

1 minute ago, rum4mo said:

No, normally nothing to do with slackening off

How do you know? The first symptom may be the fatigue failure?

What makes you think they are stainless steel?

[rum4mo]

2 minutes ago, Wino said:

How do you know? The first symptom may be the fatigue failure?

What makes you think they are stainless steel?

 

Well, they look like stainless steel, they are not magnetic I know this because I have bought a replacement set of 4 from VW - and I've used many stainless steel screws and bolts in my life time.

 

The tightening torque for them is extremely low even for an M6 8.8 grade bolt/screw, I'd think that the "anti slacken" element here is the cushioning effect of the injectors top seals.

 

Something is causing some of these bolts to fail and the only thing that I can think of is the "pumping" action of the injectors switching being amplified by the unsupported end section of the rail including the extra load having the pressure switch stuffed onto the end of that overhanging section of rail.

[Breezy_Pete]

In my experience, stainless fasteners usually have grades like A2-70, A4-80 see here for example: http://www.volksbolts.com/faq/basics.htm

 

High tensile stuff, on the other hand, is marked with grades like 8.8 as seen in photos upthread. 

[rum4mo]

Correct, but there are some manufacturers providing stainless steel fixings that meet the 8.8 tensile strength numbers, so some of them list them as being that grade, as it seems in this case.

 

Edit:- Making out the marking on the head of at least the new bolts that I bought, is not too conclusive, if I did not know better the markings could be 8.8 or 8.0 or 0.0, so after finding that some manufacturers do declare that their stainless steel fixings meet the 8.8 grade, I'm assuming that that is what is on the heads of these bolts.

Edited 14 July, 2020 by rum4mo

[Breezy_Pete]

Photo would be good.

I don't understand why you're so keen on them being stainless. 

[rum4mo]

Well, what else could these bolts be, they are zinc plated steel, they are not whatever the plating is that replaced cadmium, they do not seem to be HSS covered in a coating, they are not the old green coated ones - which you might expect as they are screwing into aluminium, ie the steel ones with a barrier coating/dip and they are not super strong Unbrako ones.

 

The new ones that I have are exactly the same to look at as the broken one in the pictures in this thread.

 

With time they have not tarnished are started to rust - so these are properties of stainless steel, are they not.

[Andymod]

In the UK any dealer which comes across a vehicle with this failure should submit a safety report to Skoda UK. This is done via the Diss system and is picked up at tech support at MK. They will then investigate and report to the relevant factory if necessary.

If you are affected then please insist your dealer submits the report. They will need to ask you some questions and seek your permission to allow to Skoda UK to investigate. This can take some time to reach a conclusion but needs to happen so that tech support are aware.

[Breezy_Pete]

13 minutes ago, rum4mo said:

Well, what else could these bolts be?

Thing is, you've recommended that people try to source stainless steel replacements of some or other grade for these, yet you don't know that they are stainless to start with. 

Not a limb I'd like to be wandering out on.

 

[rum4mo]

I've checked these new bolts again and they are slightly ferromagnetic so I was wrong in that sense, but there are magnetic stainless around.

[rum4mo]

1 minute ago, Wino said:

Thing is, you've recommended that people try to source stainless steel replacements of some or other grade for these, yet you don't know that they are stainless to start with. 

Not a limb I'd like to be wandering out on.

 

 

As you may, I was more indicating what I'd be planning to do, so there is nothing wrong with that, so what steels do you know about that are used for bolts, that look like stainless steel and are not?

[Breezy_Pete]

It doesn't matter what I think they are made of, cos I'm not suggesting anyone replaces them with stainless steel.

If you insist that I speculate, I'd say "Alloy steel"; as described in the link I posted. That covers a very large array of material compositions, probably, many of which may resemble stainless steel in appearance and properties, but aren't referred to as stainless steel.

 

Point is, stainless steel bolts are generally weaker than high tensile ones.

 

[rum4mo]

There are many ferritic stainless steels out there - but when talking in general in engineering, the phrase "stainless steel" is the generic description to differentiate from normal high carbon steels which are like Unbrako seriously strong.

 

What else are you looking for in this thread if only to nit pic on a fixing material that most people that are likely to be working on their cars or any other mechanical product, would call it?

 

If they rust/corrode in normal use on a car then they are not stainless, if they do not rust/corrode in normal use on a car then I'd call that stainless steel without drilling down to the exact version of stainless steel, I've already made it perfectly clear that my plan is to attempt to source a stainless steel fixing that is of a higher strength than that currently used by VW Group in this application - where is the error in doing that?

[Breezy_Pete]

15 minutes ago, rum4mo said:

What else are you looking for in this thread

Understanding of the failure mode, in order to avoid it?  

 

Most people working on cars know that stainless steel bolts if used anywhere tend to only be used for cosmetic, rather than structural functions.

 

17 minutes ago, rum4mo said:

if they do not rust/corrode in normal use on a car then I'd call that stainless steel

Well you'd be calling them by something other than their correct description.

 

I'm honestly not trying to beat you up, just to avoid others thinking that buying stainless steel bolts for this use is a good plan.

[rum4mo]

Honestly (back) I'd never ever suggest anyone go out and grab a correct size stainless steel bolt to replace anything, I've used SS bolts for years at work and I know exactly the trade that comes with most of them, I'll need to look back, but I can't think that I've suggested that anyone does that.

 

The point remains that these bolts are a stainless steel and picked to be that for a very good reason as having any non stainless bolts in that location would work fine - until they needed to get removed at a later date, now if they snapped their heads off then due to having been bolted into aluminium alloy, then that could require a bit of expensive machine shop work to get the bits out of a cylinder head. I would have thought that VW Group design might have considered just using the old "green coated" bolts for that and deliberately walked away from doing so.

 

Now, if I was deliberately suggesting that people should get their charge intercoolers off and swop these bolts for high strength Umbrako ones - then I'd expect to get a tanking, but I have not and will not as that would probably remove one issue and cause another.

[rum4mo]

@Wino, if you re meaning me suggesting that people attempt to source stainless steel bolts from the Swedish company I quoted, you will find that they are no ordinary stainless steel fixings, and so strength will not end up being an issue - cost will be though I'd think, oh and they list them as stainless steel fixings.