Hi,

I noticed a fuel smell in the cabin a couple of days ago, went away but back again this morning. Had a look and there is a wet area in the red circle on the picture attached. I'll stip it down and have a look at the weekend but just wondered if there are any obvious suspects on this model or anything maybe I should order in anticipation so I can possibly fix it in one session? No obvious visible drips that I can see.

Thank you.

Edited 27 June, 202527 Jun by Andy_Viking
Model Year added

So I think the wetness I could see was a red herring, I have taken the air box off to get a better look and have run the car, no sign of anything in that area or around the fuel pump, and at the moment I can't smell anything... Annoying.

You should be looking up fuel leak or "Major Fuel Leak - Due to bolts shearing on the fuel injector rail assembly" on this forum.

Lots of info here; https://www.briskoda.net/forums/topic/495523-major-fuel-leak-due-to-bolts-shearing-on-the-fuel-injector-rail-assembly/#comment-5560649

More here. Some repetition.

https://www.volkswagenforum.co.uk/threads/1-2-tsi-engine-fuel-leak.36064/?nested_view=1&sortby=oldest#replies

Your car is the "correct" age for possible "high pressure fuel rail securing bolts" issue, but I would have thought that once that started it would develop into a serious leak quickly.

What is causing the damp area on the top of the radiator?

Thanks for the replies.

Interesting stuff about the fuel rail bolts, but this problem, at least for the moment is definitely intermittent. Yesterday afternoon and evening there was no issue, and yes I agree that all the cases of broken bolts seemed to be a very rapid development into a big leak.

The damp looking area in the red ring I think was just a bit of oil, when I took the airbox off and cleaned it up it certainly didn't smell like fuel. The top of the radiator fan isn't actually damp it is just an effect of the picture, in reality that area is fine.

As soon as it happens again I'll try and get a torch shining under the manifold to see if anything is dripping down there, it is pretty awkward to see though. I don't mind stripping it down and changing the bolts and seals but seems pointless unless I am sure that is the issue.

I have used the car over the weekend, usually my wife drives it, and the problem seems to occur when the car has been standing for several hours, on start up there is a petrol smell, in the cabin and also outside the car. Nothing visible in terms of drips etc. It goes away completely after about 3 minutes and then is fine until next start up. If parked for a short time and then restarted there doesn't seem to be an issue...

Hopefully just some other issue than the high pressure fuel rail issue, and hopefully you find it before it causes any issues under the bonnet while being driven.

Tempted to just get the bits and do the fuel rail to rule it out (or solve it), doesn't look too tricky to do and not a huge outlay on parts.

Assume I would need the seal kit, bolts, inlet gaskets, I see someone else replaced the support elements for the injection rail so I'll order them as well.

I think that all VW Group workshops replace all the 5 inlet manifold screws, so I bought a set of them along with 4 inlet seals and 4 fuel rail securing bolts.

I'm planning on checking these bolts when I eventually get round to replacing the G13 coolant with G12evo.

As my wife's car slightly pre-dates this mess up, and not smelling of petrol, I'm just going to check all the fuel rail bolts for tightness for my own peace of mind.

You might have to make up some tool to remove and fit the injector support elements - okay the removing doesn't matter too much if you are replacing them with new ones, but maybe that type of tool is needed to successfully fit the new ones - I haven't worked that out.

Also a good time to take pictures of the 4 inlet ports/valves areas wrt "carbon junk accumulating" - for reference and for other forum users interest, I plan to include doing that. My wife's August 2015 Polo is at 54,000 miles.

29 minutes ago, rum4mo said:

You might have to make up some tool to remove and fit the injector support elements - okay the removing doesn't matter too much if you are replacing them with new ones, but maybe that type of tool is needed to successfully fit the new ones - I haven't worked that out.

Is this what they refer to as the 'Teflon Gasket Ring' which looks like it needs very precise positioning?

So my shopping list is:-

- Injector Seal Tool Kit
- 06M998907 - Repair Kit (Seals) x4
- 04E133036A - Clip x4
- N10546403 - Fuel Rail Screw x 4
- 036129717E - Inlet Manifold Seals x 4
- N10738801 - Manifold Screw x 5

I saw in one procedure someone ordered WHT001386 and WHT003246, Charge pipe top and bottom seals. Is it worth getting these as well?

Also, I saw someone doing the job on a VW similar engine and the injectors have a 'cage' fitted, something like this but I don't see any mention anywhere else?

Update: I have all the parts now to do the fuel rail but really not convinced that is the problem yet.

Yesterday there was a smell again on cold start and the areas in the pictures, on the lip of the air filter box, right hand side, were wet with fuel. After 2 to3 minutes driving the smell had gone and the areas in the photo were dry, and the car was fine for the rest of the day...

Sorry for missing your past 2 postings, but yes, when you remove the charge pipe you are advised to fit new O-rings, I found that the alloy top of the throttle body needs cleaning up as salty spray or as in my case, even bits of rock salt can end up in between the charge pipe end and the throttle body, and that can lead to corrosion build up which will force the O-ring to distort and cause oil mist to leak out and that will "wet" the upper area of the throttle body - so the alloy should really get buffed up with something like a "green pad" to get rid of the build up of salty corrosion.

I'll need to look at my wife's car's engine to work out what is in the area that gets wet with fuel in your car.

Edit:- getting the inlet manifold etc off will let you check if "all is well" and that that engine is not one of the ones that could end up with this problem - and so tick that off your "worry" list.

Edited 10 July, 202510 Jul by rum4mo

I've now had a look at my wife's 2015 VW Polo 1.2TSI 110PS, and what is behind there is the HP fuel pump, it has its high pressure outlet pipe on the far RHS looking into from the front, on the other side of that HP fuel pump is a fuel pressure sensor and a rubber pipe with some extra rubber protection on it, it is the LP fuel delivery to this HP fuel pump. There will also be a top seal on that mechanical HP fuel pump. Absolutely no fuel should ever end up on the outside of that area - but you know that already I suppose.

Maybe lift the air cleaner assembly up and out of the way when it is still wet and see where it seems to be coming from.

Edit:- I'd think that the HP fuel delivery pressure will be higher when the engine is cold, so if it is a HP fuel leak from that area, ie pipe or sensor, then it would be worst then. I've never checked the fuel delivery pressure at cold or hot so I can't comment on how much it gets varied by, from memory, there is another HP fuel pressure sensor on the LHS (looking in to the engine) - on the end of the fuel rail.

Next Edit:- sorry I've now re-read your earlier postings and see that you have already taken the air filter off and not found any useful clues, how annoying! Keep trying.

Edited 11 July, 202511 Jul by rum4mo

Thanks, I am going to have a go at this hopefully Friday, weather permitting. Procedure looks fairly simple, the only odd thing I don't quite get is it says to remove the high pressure fuel pump, I can't quite see why that is necessary but may become obvious as I strip it down. That said, the procedure I have is for a slightly earlier model.

So I am at a bit of a dead end.

Stripped down this afternoon. Top of the inlet manifold has some suspicious looking wet patches at the right hand side. Fuel rail bolts are fine and no evidence of current or past leakage below the manifold. The only two places I can see that fuel could get onto the top of the manifold are from what I think is the fuel delivery or return pipe, goes across the top of the manifold between the pump and the left side (but that looks fine), or is it blowing some out past the inlet manifold gaskets when cold? Is that even possible?

Edited 18 July, 202518 Jul by Andy_Viking

Reassembled with new manifold gaskets and bolts, ran with the airbox off, and bingo, got it!

Pinhole in the low pressure delivery spraying exactly where the manifold was wet. I think moving it around to get the manifold off must have made it worse as it was really spraying out...

I don't suppose anyone with the software could look up the part number for me please?

Good find!

There are a couple of part numbers depending on which PR code your car has:-

For PR TP1 the p/n is 04E 133 723 CN

For PR TL1 the p/n is 04E 133 723 CP which has been superseded by 04E 133 723 GN in 2023

Now, this is when my usual advice to get hold of a copy of your car's "CAR DATA" from a, in your case, Skoda dealership, is worth having, as it would make it clear which PR code is relevant for your car - what the differences are between them both I can't say.

One other thing, you are possibly lucky, as the version of that delivery pipe fitted to my wife's 2015 VW Polo 1.2TSI 110PS and so age Fabia and Ibiza etc, is almost twice the price of the one fitted to later cars regardless of the PR code!

Or, is this cheapness/cost reduction the reason why your delivery pipe has failed? (maybe not related in any way, but it does make me wonder as the price has been halved when it has been revised for later engines only.

Edit:- by the way, the diagram shows the same sort of design for both delivery pipes and they are "one piece" from the RHS of the bonnet area to where they terminate on the HP fuel pump - using constant tension metal clip, p/n "N 910 203 01 Spring Band Clamp 14.5 X 12"

BTW, did you need to remove the HP fuel pump - as your guide suggested?

Edited 19 July, 202519 Jul by rum4mo
Adding extra info

Thanks. Annoying that it is the full delivery pipe at £150ish. For now to get it back on the road I have used some high spec 8mm fuel hose with proper clamps to just replace the short perforated section, and the hose actually looks better quality than what was previously fitted. It is only about a 4" section between the end of the stainless pipe and the fuel pump itself.

I will make efforts to find the PR code for this car, thank you.

The guide I had found wasn't particularly accurate, no need to remove the high pressure fuel pump. It was a really easy job, couple of hours max and that was taking my time. I think had the injectors needed removing and resealing it would have taken an awful lot longer. I now have all the bits to do that plus the tool kit, more items for the 'stock room' :)

Edited 21 July, 202521 Jul by Andy_Viking

I don't suppose that you had the time or reason to check the 4 inlet valve areas - really just to check on the level of carbon build up on the backs of the inlet valves as they don't get washed by petrol on these DI engines.

From your pictures, it does look a lot like the short final length of flexible pipe could have been offered as a spare part, so as it's a low pressure fuel line at that point, what you have done sounds like being a good enough fix.

That price scares me a bit when you consider that my wife's slightly older car's price of that delivery pipe is listed as being twice the listed price of your one - unless that is an error in the parts listing I use.

I did mean to take some pictures but got so engrossed in what I was doing I completely forgot. The inlets all looked pretty clean, as good as any similar mileage engines I have dismantled in the past with conventional injection. This car has done 80,000 miles approx.

That sounds promising - I should end up looking at the ones in my wife's 2015 55,000 miles Polo 1.2TSI 110PS soon, after I pay an indie to replace the cam belt etc, just to be safe.

Edited 22 July, 202522 Jul by rum4mo