Can water wetter substitute for radiator fluid or is it an additive only? That is, can I fill the whole radiator up with water wetter or is that not not advisable?

This should be completely obvious. If there is no water, what exactly is it going to wet? I don't know why you would want to spend $8 a pint for all of your radiator fluid anyway. It has two purposes: 1) add it to a normal antifreeze/water mix to increase the overall effetiveness 2) add it to straight water for the same thing but also to prevent corrosion. Plain water is more effective at cooling than antifreeze and water but will corrode the block very quickly. Please note that you must replace it with antifreeze in the winter or you will imediatly desroy your engine beyond any hope of repair. Mostly only race cars go with straight water.

i dont udnerstand you

What is water wetter? Sorry but I've never heard of it or even seen the product.

it's coolant

Redline Water Wetter is a cooling system additive that aids in the thermal transfer of the liquid its mixed with. It is not a replacement for coolant or water.

thanks that's all i wanted to know
Redline Water Wetter is a cooling system additive that aids in the thermal transfer of the liquid its mixed with. It is not a replacement for coolant or water.

It's like soap, it lowers the surface tension of water. This allows the water to have better contact with the block and radiator, thus be more effective.

you can run straight water, straight coolant, or straight water wetter, all would be fine. the best combo IMO is a water wetter/water blend. coolant is only necessary in below freezing climates

All 3 of those are wrong. Striaght water will cause terrible corrosion, straight coolant is not at all efficient and freezes at a much higer temp than coolant/water, and water wetter actually makes water wetter! Without water it can't do its job. Can you wash your clothes in straight laundry soap?? Technically you could put apple juice in your radiator, so do whatever you want.

i've seen several engines run only water or only water wetter with no issues at all. and these are track cars and track bikes that get a lot of use/abuse

A friend of mine once used cherry soda for brake fluid. Would I reccomend it? No.

you can run straight water, straight coolant, or straight water wetter, all would be fine. the best combo IMO is a water wetter/water blend. coolant is only necessary in below freezing climates

All water, all coolant or all water wetter is wrong and a bad choice. All coolant will absorb less heat. All Water Wetter is just silly. All water, as Layne said, will corrode the hell out of your system and cause premature pump failure.

Straight water is ok temporally, and works fine if it isn't really hot or below freezing. Us poor people find ways of testing the limits and tolerances of are vehicles. Just like brake works wonders for leaking power steering pumps (stops the leak). And yes I know this will inevitably destroy the pump, but it's no good anyway and have been planning to replace it that was 1 1/2 yrs ago.