Breezy_Pete

Yep, should be a chunk better. I get 42 on almost exclusively 5 mile each way suburban commutes. 55kW manual.

Good morning and welcome.

I care about statistics because they can provide me with vastly more data on any given subject than my own personal experience. Not much to do with the topic though.

If 16-valve, manual or automatic transmission?

Can you explain your thinking there, please? Don't see the mechanism for that, but interested to learn.

Not uncommon for radiator fans to not be working on at least one of their speeds. Both should run simultaneously. My recollection is that on 9N Polo/Mk1 Fabia the on threshold for low speed fan action is 9 bar refrigerant pressure at G65 sensor, switch-off at 6.8 bar. High/full speed fan action triggered on at 16 bar and off again at 12. Some of the smaller fans are single speed, coming on with low speed main fan, staying on with full speed main fan. Things are a bit different on recent cars with fan control module integrated into main fan and continuous speed control, but I believe both fans still run together at same speed when working right.

Worth being aware that the stronger common grade of stainless (A2) is weaker than even 8.8 grade high tensile, so don't use them for anything that needs strength.

I like to use older cars, from say year 10 of their life and more or less until scrapped. When I do change pre-scrappage it's reason 3, where desireable = price in hundreds rather than thousands.

Pleasure. All 12V sockets look to be fed directly (via nothing but fuses) from battery positive, as I naively expected. Nothing fancy.

Very common problem. I find it quite surprising these days when I come across a (VW group) car that hasn't got some degree of splitting in these areas. Some are just hideous/obvious but it can be quite subtle in the early stages. Look/feel on the underside as well as visible parts. Here's an end-stage one on a mk4 golf; sounds like yours may well be similar.

Fit a new fuse there to rule out a 'hard to see' break.

There's one particular feature of the current flow diagrams that people often struggle with; wire continuations marked by rectangular boxes with numbers in. Every page/diagram has a set of incremental numbers going left to right along the bottom; and within each functional group of pages they increase from 1 to N continuously as you go from one page to the next. Where there are numbered rectangular boxes on the ends of wires, it is these numbers along the bottom that they are referring you to, to find where that wire continues. Once you get to that point, you'll see a corresponding rectangular box with a number that refers back to where you just came from. These numbers along the bottom are known as current track numbers or current path numbers. This document may be rather handy to refer to also: CFD explanations.pdf

Yes you should. 35Nm is recommended I seem to remember. Easy fix except for the access.

Seems very unlikely to me that there is any link between that fault code and a misfire on a single cylinder.

Look for a wiring connector onto the main fan and disconnect it if you can, then have a look at the contacts inside the connector, see if there's any water in there, or evidence of corrosion.

First paragraph sounds spot on to me. Dead easy to measure, super simple and appropriate.

Well done @skoman and thanks BXEman for an entertainingly informative account.

Complicated to the point of being very impractical to calculate fairly and implement, unfortunately. Energy usage numbers are directly proportional to CO2 production for IC-engined cars, which is one of the reasons that is currently used. For electric cars it should be easy to measure as Watt hours per unit distance travelled.

Second question can be answered by close up visual inspection. One side of each fuseholder may (or may not) be part of a 'busbar' linking several fuse positions, the other side will typically be a terminal on the end of a wire. If one or both sides are empty of such contacts (no metal visible), a fuse fitted there will do nothing. (Although a piggy-back one might, if there's one terminal and it's live, I guess, if fitted the right way round; never used one, someone else will confirm. Unlikely to be secure if held in at one end only.) Use your own, or borrow or buy any handheld voltmeter to find out the answers for the first question. It can be a £5 one or cheaper if you can find one. Set to read volts DC, put negative probe tip onto something metal connected to chassis/body, positive probe onto each/both of the inserts in turn that the fuse pins would contact if present. Try with ignition off/key out first, if you get 12V from either side of that fuseholder position it's a permanent 12V; if not it isn't.

Fair point. I wasn't particularly thinking that it was definitely leaking, just a bit surprised to find it, and was hoping others might explore for the same thing on their - perhaps older - Fabias (or any other VAG cars with the same bottle) to see if this is a common thing. At some point it's going to fail to seal fully, if the dent keeps getting deeper.

How to know what level the pressure is at though?

Topping up coolant last evening I happened to run my finger down the neck of the coolant expansion tank. Was pretty surprised to feel a distinct indentation in the surface right where the cap's o-ring sits. Comparing with my Polo there's a just-detectable one on that too, but the Fabia's one feels big enough to possibly affect the o-ring's ability to seal as intended. Don't try this unless the engine is cold, but have a go yourself and see if yours has a similar 'print' of where the o-ring's been sitting for the last 13-20 years. Little vid showing the highly technical experiment in action: 20200818_184247.mp4

Probably item 15 here: https://skoda.7zap.com/en/cz/octavia/oct/2010-663/9/906-906015/ As opposed to items 10 or 12, which logic suggests would be temperature sensors 2 and 1 respectively? I would expect AMD to know what he's on about though, and if you look at this diagram, it does refer to a cat in the title: https://skoda.7zap.com/en/cz/octavia/oct/2010-663/2/253-253063/ Hope I'm picking the right engine code diagrams for your car.

May be normal since the torque 'spikes' on diesels are bigger than on petrol engines. Does the alternator have a freewheeling pulley or fixed?

Does the fuse seem loose in the contacts it plugs into? Is there any corrosion/burnt appearance on the fuse pins?