A few days ago, I experienced a temp excursion on my Felicia.

We argued with @R_Blue , he claiming the Felicia radiator is insufficient and that is the only reason.

My Perspective on the Matter:

I, on the other hand, have a completely different view.

If the fan is operating at speed 2 (250 W) and is triggered due to refrigerant pressure, the following occurs:

The fan motor generates significant negative torque if it is forced to overspeed by the increasing airstream velocity caused by vehicle movement.

However, the fan blade design does not allow efficient overspeeding of the motor. As a result, fan RPM remains nearly constant regardless of vehicle speed.

This means that the airflow through the radiator is effectively capped at the maximum flow rate provided by the fan and any leakage around the shroud.

As vehicle speed increases, the static pressure behind the radiator shifts from negative to positive, potentially stalling the airflow through the core and further limiting flow to the level provided solely by the fan.

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To prove my point that the Felicia radiator is not inherently insufficient, I compared its dimensions to the Grande Punto radiator (used for both 1.4L petrol and 1.3L turbo diesel engines):

• Felicia fin stack: 488 × 285 × 34 mm

• Grande Punto fin stack: 540 × 375 × 26 mm

Assuming equal fin density, this means the Felicia radiator has only ~11% less fin area than the Grande Punto's — and keep in mind, the GP radiator is shared across multiple engines.

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The only firm conclusion we can draw is that the Felicia radiator, being thicker, requires greater static pressure to achieve the same airflow. This is also reflected in its fan design, which appears optimized for static pressure (using straight blades), rather than high airflow volume.

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Conclusion

I believe the Felicia shroud should be modified to include rubber trap doors (shroud flaps). These would allow airflow to bypass the fan when static pressure builds behind the radiator, restoring flow efficiency during high-speed driving.

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What’s your opinion on this approach?

I know you won't value or like it but here it is!

You could be right, partial right or wrong or partially wrong - unless you know otherwise you have made a lot of assumptions and not provided actual figures or conformations. Rather than theory figures and calculations do you have any real world test figures.

Are the FIAT and VW rads made by the same supplier to same or similar build, are the fin stacks same dimensions, internal tubing the same, tanks and bottoms, capacities, inlet and outlet sizes, etc.. You say the VW rad is thicker.

Get some metering equipment on the car and measure at different points to the rad in different driving conditions, repeat test to same conditions to confirm readings.

Theory is fantastic until it meets the real world, as Mike Tyson put it on being told an opponent had a plan to beat him “Everybody has plans until they get hit for the first time”.

Brera rad meant for 3.2 litre engine is 649 x 456 x 32 so it has double the S.A. of felly and it's meant for 260 BHP 3.2 V6

I am very, very confident Felicia's rad is rather large

Mito which is a diesel 90hp has 620 x 395 x 27 around 30% larger and newer 85hp variant has 620 x 392 x 16 so in that case felly is 18% larger. Soooo yeah

Yeap that'd be great for comparing surface area(?) (why put S.A.) but you're not just comparing rad surface area, or rads, in isolation, these are different rads in different cars. As an engineer don't you want to test and confirm your theory with actual real world measurements, those without engineering qualifications manage this.

S.A. could also stand for smart arse, those that act as a smart arse sometimes end up with an arse that smarts from it being dusted with a toecap, all figurative meanings of course but bear it in mind if you ever go on real world sites. I'm sure you know from your previous experience if you carry on like that in the UK you'd have the urine extracted from you left, right and centre.

I'm not saying you're wrong, I don't know, I'm just saying prove it rather than what you are saying which is you're right because you're right.

You asked for opinions of your approach, more valid and valued opinions to you than mine I know, but my opinion on your approach is that it's flawed.

Everyone is welcome to my opinion (whether they want it or not). 😁 I'll bow out and leave the thread to yourself and others now.

Felicia Radiator was originally designed for Skoda 120 - a car with nearly half the power and no AC condenser in front of it. The fan shroud was designed for larger 1.6 radiator that doesn't cover around 10cm on the right side... Add current heat waves and sediments over past 25 years.. I wouldn't be surprised if the rad was insufficient.

Does the Grande Punto come with AC?

I think I have better comparison - Fabia with 1.4 Skoda engine.

Non-AC - 6Q0 121 253 AE

dimensions - 430x413x23

AC - 6Q0 121 253 R

dimensions - 632x414 (ETKA doesn't list thickness, but I found 23mm aswell?)

The larger rad was used for 2.0 engine.

Another case is Felicia 1.6, which used larger rad for AC version.

I think it's another case of "good enough", as they didn't want to rework the cooling circuit to fit a larger rad... It will work, but you can hit it's limits pretty soon.

Edited 4 July, 20254 Jul by Papez

1 hour ago, Papez said:

The fan shroud was designed for larger 1.6 radiator that doesn't cover around 10cm on the right side

on mine it fits like a glove on the 1.6 its a bit missing

1 hour ago, Papez said:

Does the Grande Punto come with AC?

yes it does

1 hour ago, Papez said:

Non-AC - 6Q0 121 253 AE

430 x 431 x 26 = 4.617.340

1 hour ago, Papez said:

AC - 6Q0 121 253 R

630 x 415 x 23 = 6.013.350

16 hours ago, Thefeliciahacker said:

Felicia fin stack: 488 × 285 × 34 mm

488 x 285 x 34 = 4.728.072

So its comparable to NON AC FABIA

but always no full shroud

only brera has full shroud

but a much much larger fan meant for airflow and not static pressure

while felly has a fan optimised for static pressure if ive ever seen one

Edited 4 July, 20254 Jul by Thefeliciahacker

18 minutes ago, Thefeliciahacker said:

but always no full shroud

That was later in production, originally it was full shroud, but with an extra fan

20 minutes ago, Thefeliciahacker said:

So its comparable to NON AC FABIA

So it could be combination of both factors... Small radiator blocked by the evaporator and shroud.

For reference, the 1.6 radiator is 285x590, 1.6AC is 322x590.

There was also Favorit rad for hot climates, that had same dimensions as the 1.6, but 1.3 outlets - that would suggest that the stock rad indeed doesn't have much headroom... Unfortunately that radiator probably wouldn't fit on an AC Felicia, even if you were lucky enough to get one.

BTW, I also experienced slightly higher temps on highway during heatwave. That was with small fan and without AC. But also stock 20YO radiator.

Edited 4 July, 20254 Jul by Papez

On 04/07/2025 at 14:46, Thefeliciahacker said:

on mine it fits like a glove on the 1.6 its a bit missing

I have posted in the past photos of mine (with A/C) there is no space to fit a larger radiator (ftom th 1,6) because the aircondition pipes are obstructing the fitting.

11 hours ago, D.FYLAKTOS said:

I have posted in the past photos of mine (with A/C) there is no space to fit a larger radiator (ftom th 1,6) because the aircondition pipes are obstructing the fitting

you are right on the ALEX ac you cannot

I remembered these:

"It's a liquid cooled engine. Cooling the engine bay doesn't do much.

"Felicia has a big hole under the engine, I could feel hot air coming out of the engine underneath and the car - and that was with the weak motor of the non-ac 1.3. With AC, you have two speed fan, if it's not kicking to second speed, you have plenty of cooling."

I think you have misinterpreted what's popping

If you can design a different type of fan blades or install a most powerful fan from another model then go for it.

I have opened in the past a topic about an auxiliary electric fan.

I think my contribution in this topic ended...

Yeah, it will be on the plans