Papez

This topic covers conversion to AFH and AVY engines. AUA should be similar to AVY, but it has alloy engine block, so you might bump into some new issues. I'm not sure if such conversion was ever attempted, because AFH is more straightforward and more reliable option. I cannot help with availability, since I don't live in the UK But they were quite common in 6N2 polos, Lupos, Arosa and 6k2 Ibiza/Cordoba after 2000 as replacement for AEE. There's one more option for EU4 engine - Fabia had EU4 variant of Skoda OHV engine between 2001-2003, with Skoda gearbox, but changes were so extensive, that I think that VW engine is easier conversion...

Just to be clear, which engine type do you want? I'm asking, because AUA/BBY engines found in Polo/Lupo were already Euro 4, just like Fabia until MY2010.

It is possible, but it requires modification of chassis rails, modification of driveshafts and other problems - amount of work required is shown in 1.8 transplant threads - it's not worth it, if you want to uprade just to 1.4 engine.

Yes, because its adaptor plates were made for engines used in Polo (and other small models) with 085 gearbox. Lupo was last VW with that gearbox. Fabia and other newer models used stronger gearbox, which required different pattern. Here's picture, which compares AEE from Felicia and Octavia - Fabia 1.4 has similar pattern to Octavia.

There's thread on this forum about fitting 1.4 16V engine from Polo 6n. It can be fitted to Felicia gearbox using 1.6 mounts, only driver's side engine mount has to be fabricated and newer engines with crankshaft sensor might need some modifications on gearbox adaptor plate. Fabia engine has same block as later Polo 6n2/Lupo engines (engine code AUA/BBY for 55kW), but different gearbox pattern, because of different gearbox. That might complicate things.

It's switch from Metra Šumperk (OEM supplier), type TH 470.1, with on temperature 85+-3°C, off temperature >77°C. I'm not sure, if they're still available, but as Thefeliciahacker said, you can find switches with similar parameters from other manufacturers.

I'm affraid there are no other consoles that'd fit, without some modifications. That issue with knobs might be solved by switching left and right backreasts. Seat frames in felicia are symmetrical. But plastic side covers need to be modified for that.

That delay is caused by switch being on output of radiator, which is coldest place in circuit. Even when thermostat fully opens, coolant has to go through whole radiator before it reaches switch, which takes some time on idle RPM. I replaced switch on my Felicia with Estelle one, rated for 80°. Fan kicks in within a minute after stopping, by then, engine usually already has 95°.

Yes, they fit under seat rail. I read something about collisions with seat in rear position, but I cannot confirm that, since I wasn't able to get one...

Only armrests for Felicia I'm aware of were sold by Milotec, but they are not available anymore. Maybe it would be possible to modify armrest for different car models - similar armrests are sold in UK by Kamei. (Image "borrowed" from a market site)