BazzY

Thanks for reporting the outcome so others have a solution ! Nice Job - Shame about the O-ring !

I use the ALCAR (Eurasteel) 8667 with a cheap 205/55 R16 tyre. Works for me. Octavia 3 1.6 TDi 2017.

Can't comment on the original "will it fit" question cos I haven't tried those sizes. I agree with your opinion that the lower profile tyres are a pain - uncomfortable ride, worse for aquaplaning, expensive tyres. My Octavia MK3 1.6 diesel SEL 2017 is on 205/55 R16 as standard and I'd recommend this as a decent compromise (I run all-season tyres - good all round but a little noisy). There are loads of Octavia and Golf 16 inch wheels around and they're so common the tyres are reasonably priced. Just my suggestion !!

PS. Please post back here to let me know if it works - then others will know this is a viable solution.

Glad to be some help, Hope this solves your problems.

I recently had the same issues with a 2015 Golf MK7 1.4 tsi 125 bhp, very similar vehicle and engine. Replacing Temp sensor did cure it. The Bilstein Temp sensor you have identified appears to be correct for both this and the Octavia. It is at the back of the cylinder head (i.e. towards the bulkhead) towards the left end (i.e. gearbox end). Pretty well hidden by pipework and turbo stuff so that access from the top is very difficult. Working from underneath the car I could see it. There is a curved plastic shield which curves part way round the drive shaft, mounted by two bolts. Once that shield was removed I was able to reach an arm up behind the engine to get at the sensor. If I remember rightly it was secured by single bolt with 10mm hex head. I replaced mine with a Lucas branded one from NAPA but the O ring of the new one leaked so I had to take it out again and fit the old O ring with the new sensor . Note that there is a small "support ring" also fitted between the O ring and the cylinder head and this may or may not come out with the sensor. It can be removed with a small pick or spring hook ( or a tiny cranked end on a straightened paper clip ! ). If everything else is still in place you will lose very little coolant doing this without draining the system. A bit fiddly getting the securing bolt back in but you can do it this way. Sorry no photos, I did this job a few months ago. Good Luck.

PS. Try watching a few of the relevant videos on YouTube to see what others have done.

When working on cooling system recently on 1.4 tsi Golf and 1.6 tdi Octavia I found this tool very useful. saved a lot of bother with clips at awkward angles. https://www.screwfix.com/p/silverline-flexible-ratchet-hose-clamp-pliers/404fu . Still not perfect or easy though. As for the original question - ref. vacuum kit - I wouldn't bother. I'd only drain the system as far as necessary for the job in hand and refill "old school" with G12 Evo. Run up to temperature with filler cap off, then cap on and several short runs with a close eye on temperature and coolant level checks after. Note some dealers have quoted 4 hours labour for a simple drain and refill using the vacuum kit several times over. In my experience it's almost impossible to get more than half of the coolant out without disconnecting every hose in the system. If enough vacuum were applied to really do the job it would risk damaging some part of the system. Either way you cross your fingers and say a small prayer.

Yes but which relay ??

So it depends on whether it's manual or DSG transmission ! And possibly also on trim level and year of manufacture, - Very reassuring for those who have to jump from car to car and just drive off I don't think !!! Well done VAG !

I think you will find that this is exactly how the ACC is designed to work, even though it seems stupid. We have a Golf with the same system and the Owners Manual clearly states that the ACC will not bring the car to a complete stop but will disengage at 20 km/h or below. The "Front Assist" however does operate at below 20 km/h and will apply emergency braking to avoid collision - though I would seriously avoid relying on it. The two systems are separate and switch over at about 20 km/h. I agree it's crazy but that's the way VAG designed it. I doubt that you will be able to do anything about it with VCDS and remember if you try to you are interfering with the cars so-called safety systems which may be dangerous !

But does anyone know where to find and identify the headlight washer relay - my VCDS says it's dead !

I've seen the boot problem on 2016 Fabia before - in our case we managed to open it by pushing down/in on the boot lid while pressing release button. A spray of 3 in 1 oil in the nooks and crannies stopped it from happening again. Hope you are lucky and find an easy solution. Could also just be low battery if it's stood idle for anything over a couple of weeks.