How effective are swirl pots in adding cooling? I have a 2.0L zetec and am using an original lotus 7 S2 radiator.....and I'm concerned on how effective the cooling arrangement is with this small radiator.....and wonder how effective swirl pots are. Obviously there is the extra surface area of the pot for heat transfer.....I'm more wondering how effective they are for removing air form the cooling stream

That's a bit like asking how effective a car is!

They remove air from the water, but if you have a cooling problem then a swirl pot isn't going to solve it on it's own.

Basically you need a radiator which is big enough to keep the engine cool in any case.

The swirl pot adds the advantage that you can run with a lower water capacity system and it will still de-aerate effectively (which normally is done by having fairly large reservoirs of water in the tanks of the radiator and header tank etc)

Swirl Pots don't really aid cooling, they just stop the air bubbles creating hot spots on your cylinder head and block...

You can also add water wetter to stop steam bubbles forming in the water (like around the element of your kettle) which can cause the same thing...

They are extremely effective in removing air from the system, in fact I wouldnt run without one on our cooling compromised cars...

As NS said, there is no substitute for a big enough rad tho...