I use it. Here's how I add it. Wait till the car is cold (sitting overnight is good) Open the radiator cap, siphon out some of the coolant then add the water wetter and add back enough coolant to fill the radiator. You can put the extra coolant in the overflow it won't hurt anything. Keep in mind coolant is toxic, don't siphon by mouth use a turkey baster or something and then throw the baster away or use it for a brake fluid change or something. Mark it somehow not for food use though if you keep it.

 

It raises the boiling point of the water simmilar to antifreeze, plus it has some additives in it that keeps the water from "clinging" to the metal. I used it in my race bikes, and noticed that the radiator fan rarely kicked on as a result. Not sure if it applies to Impreza's, but I thought id chime in.

-scu

 

The stuff works great. We used it in our rally car because we had overheating issues and it helped solve the problem.

 

Have you used it actually used it? Or are you making a guess?

I think it does more than that. It reduced my temps by around 10F. I used it in a previous car that had the type of overflow tank that was pressurized and you can see in it. Before using WW, after an auto-x heat you could see the coolant boiling inside the tank. After adding it I never saw it boil inside the tank again.

PS My company makes Soft Soap and it would not stand up to the temps.

 

I know. I spent over $3k fixing my head gasket problem (98 DOHC), and I had Water Wetter installed. The difference is that Kanga (98 Forester) runs one line lower on the temp gauge.

[monkee's tune]...... and I saw her gauge, now I'm a believer, there's not a trace of doubt in my mind........[/monkee's tune]

(If you don't know this song, it was remade for the movie 'Shrek')