Papez

If both tubes are warm while driving, it would mean that coolant goes through the radiator, but radiator doesn't cool it. Could you check whether the entire area is warm on idle? Is it car with AC? There's no relay, if it's not. If it has AC, the fan should turn on immediately once you turn on cooling. Just to check, what temps are we talking about?

Problem 1 - The fan switch sits in the radiator, if there's no flow to the radiator, it won't turn on. Check if the tube going to the radiator warms up when it sits on idle. But ito Sunds like the thermostat is not working properly (it can happen even with new thermostat). To rule this out, you can remove the thermostat valve. Do you mean high/low beam switch? That might be faulty switch in the lever itself. Yes, it might be a symptom of misaligned geometry, get it checked. There's a circuit that simulates function of a newer car - the radio stays on as long as the key is in the ignition. https://www.sp-el.cz/Felicia-S-kontakt-d1149.htm#detail-anchor-description Reverse is meshing a gear between other two gears - if they are rotated in "right" position, it won't fit, especially if the gear is a bit worn from skipping teeth by shifting reverse in movement. What helps is to briefly release the clutch in neutral to spin the gearbox. It's an old car with cable operated throttle, so sudden release rapidly reverses torque going from the engine (newer cars have electronic throttle valve, which is slower in those situations exactly for this reason). The engine is mounted in rubber bushings, which shift from one end position to other and then flex a bit, which is the jumping you describe. Worn out mounts can make this effect worse.

No That is correct. The rubber is flexible enough to take all movements, so there's no sliding that would wear out other parts. It's like that on most newer cars, MK1 Octavia even has main bushing mounted horizontally. The bushing just has to be installed correctly, so it's not loaded when the car is standing on wheels. Found a nice video that shows the bushing movement

This depends on fan's thermoswitch - stock on a non-ac Felicia is TH470.2, which set quite high, at 97C +2/-3.. Add delay before the hot coolant gets from thermostat to rad output, older switch that can drift from rated temp and you can get close to 110° quite easily. My point was, that temperatures beyond coolant temp aren't rare, so even exchanger can have a positive effect. Which is probably why VW slaps it on almost every engine, except those that needed it the most 😁

Sounds like the engine wasn't running at the end of the video.. but the "heating up at idle" part went up to 106C. Before the radiator fan turns on, the coolant can reach around 100-105°. Since the oil at this phase cools only by contact with the engine block (no airflow around the oil sump), these temps are IMO not impossible. I tried to find some data about oil temps on stock engines, and found a topic where people reported temps of newer Skodas with 1.0 N/A engines (no oil cooler) - they go up to around 130° on highways, 110 is standard temp at lower cruising speeds. TSIs with heat exchangers usually top around 110C. Someone mentioned old 1.2 three-cylinders, they supposedly went up to 150C, although that's unverified, oil overheating due to heat from the catalytic converter is a documented issue on those engines.

It uses thermistor with known characteristics. As long as you use a thermistor with same characteristics, it'll work, it doesn't matter how it's encased.

Which is the case without oil cooler as well... Idle, no load: (Isn't it funny that TC-6 can show more than 100C, so it can be used to monitor coolant/oil temp? 😁) So in this case, water/oil exchanger is better than no cooker at all, although arguably not as good as proper coolwr. On the other hand, it helps to warm up the oil as well and keeps stable temp without additional components and high pressure hoses.

I found mention in Andrt's book, it says special/optional equipment but nothing about origin.. and no mention of thermostat. Trying to find some more info, I only found some old listings, showing that it was made by Autopal (manufacturer of the factory coolant radiators) And photos of installed cooler

Does a stock engine need anything more than that? @R_Blue - what book is that? Oil coolers were used on some rear-engined Skodas before introduction of alloy oil pans, but Favorit?

That's just useless filter thatblooksnlike IR imaging. Phone camera isn't capable of detecting IR range that's needed for that. That requires specialised HW (which is available as smartphone addon at same price point as the phone itself)

the aluminium pushrods have steel ends. Like this: The heat exchanger comes from Felicia 1.9D or similar: Unfortunately it requires a custom part due to different threads between Skoda and VW blocks. I remember seeing a drawing, but cannot find it.. I also found mention of a Renault heat exchanger which is supposedly easier to fit, but I found no more info apart from this picture

Not tappets, pushrods. Injected 135/136 engines have aluminium pushrods for intake, steel for exhaust.

I haven't heard of any factory cooler on front-engined Skodas, do you have some more info? A relatively common modification is oil/water heat exchanger from VWs - an aluminium cube that fits between the oil filter and the engine block. It only requires custom tube to fit the oil filter and some pipe work for coolant. This already solves the temperature regulation issue and it's good enough for more powerful engines, so it should work.

Not always, various broken plastic parts in the housing can make the valve inoperable even when the core works. The car I'm refering to has broken plastic part that the valve pushes against to open, so it was stuck closed.

I'm not sure which part fails when the thermostat doesn't close, but I had failed thermostat in closed state on a 1.4 VW engine and option A fixed it.

Older models can be opened with a string. Newer models have a small cover around the locking pin, that might be harder.

Yes, you can put a plate there, but due to play in the linkage and engine movements, the slots won't correspond - Felicias often has problems to fit into rectangle in the center console 😁 Maybe, if you converted the gearbox to cable shift with tight tolerances, (check Octavia AZE or Lupo AHT), you'd have some chance with this idea.

The difference between Testarossa and Felicia, among other things, is, that testarrosa doesn't have a meter long sloppy linkage between the gearstick and the gearbox.

The Polo gearbox is PoS, so Felicia would be a better choice. However, you need the adaptor plate and flywheel that were used in 1.6 Felicia to make the AEE work with Skoda gearbox.

I had exactly the same experience - it was the ignition switch. It was just ocassional malfunction at first, it became more common over time. Ended up not being able to start at all - luckily it was next to a shop with electric equipment, so I could get a piece of wire to connect the starter directly to 12V. Curiously, I could sometimes hear clicking of the starter solenoid - guess that switch let some current pass through, but not enough to pull the contacts.

Have you tried swapping back the old crankshaft sensor? It still sounds like the new one isn't working.

As long as you have functional thermostat and cooling fan system, right pressure, no gas in the system and working radiator, it doesn't matter what liquid is in the system. Coolant has two jobs - anti-freezing and anti-corrosion.

I was quoting @D.FYLAKTOS who's confusing timing belt with auxiliary belt. AEE is an interference engine, which means that snapped belt will lead to rather expensive damage. So keep factory service intervals.

You have a 1.3 with a timing belt?

Are you ola Škoda already did that 😁 Felicia with EDS used Octavia ABS unit. You can take a look into documentation for inspiration. Are you swapping the Golf gearbox with the engine? The instrument cluster looks great. I always wondered, why Felicia didn't get something more modern than mechanical speedo, VW instruments fit perfectly.