2nd radiator?
 

I am trying to get my grillblocks right. And i.m on the edge of getting to high. My temp went up to 98/99°. So i turnded the heater on and cracked the window. And it went down to 90/92°. So it got me wondering. How about a 2nd radiator, flat on the belly of the car. Even better if you can make it flush with the belly pan. Put some aluminum L strips on it inline with the car. Then take a 2way valve from a heater and install the control in the car. So you can make a smaller grillblock.

I think unless you can find a really cheap radiator you will never break even. That's the problem with a lot of mods, it's hard to ever break even.

I know what you mean. But at the junkyard you have to look for an old one. Also the 2way valve has to be old. Because of the more simple setup. But i would think you can keep the temps down so that the fan doesnt have to come on.

I would not bother with a full block and an extra rad.
The aero gain from a full block compared to a near full one is minimal.

You need to be very careful with (near) full grill blocks as you run the risk of raising the under hood temperature too much.
Sustained temperatures higher than 40°C / 104°F can damage the 12V lead acid battery.
Cars with EGR also do not benefit from really hot air; mine does best at 30°C.

You need to monitor the engine air intake temperature. That is a good indicator of general under hood temperature.

Another good one is coolant temperature.
My car opens the valve partly at 81°C and fully at about 91°C; I guess for me it is best to keep the temperature in that range.
I have an UltraGauge set to monitor both IAT and coolant temp. I add to or remove from my grill block to keep in range.

On my Saturn I cometely blocked the front end and converted it to bottom breathing using an air dam mounted directly under the radiator. It served the double purpose of cooling the rad and as a dam, blocking some air from going under the car. I'm not sure how the Ka is laid out but it might be worth 6ft of lawn edging. Adding another rad defeats the purpose of the block because you are adding weight and complication that is unnecessary when the problem could be solved by just blocking off less area.

cooling system adjustments
 

I had an 85% lower grill block with the original radiator, 77/170 degree thermostat, and the coolant temp was getting way too high when going up hills.

I changed to a 66% lower grill block, put in a dual core extra capacity radiator, 82/180 degree thermostat, and now the coolant stays in a very comfortable narrow range, reaching a max of 97/206 at the top of long steep hills on hot days.

The old radiator was thin, beat up and falling apart. I put a screen in front of the new one, and periodically take it out to brush off the bugs. The larger lower grill opening combined with keeping the radiator fan off has resulted in the mileage increasing. This took some experimentation to accomplish, which was well worth doing to get the results.

Have you added ducting from the grille opening to the radiator? If you're not willing to dial back the grille block, this could make your cooling system efficient enough to bring the temps back down a bit.

I'll make a pic tomorrow to show the mockup. Its almost back to original sice. But now with smoothed bumber. And i have a realy small radiator. In cm its about 40x60/70. So it would get hot quick. And i live in the netherlands (flatlands) a "hill" here is maybe 30meters high. Highest point here is around 380meter. And thats 300km away from me :-p

What this guy said, get a "bigger" radiator. They come in "cores" like computers do . Most cars have a single core radiator. High performance cars can get a 4 core radiator for increased cooling.