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Water Wetter vs Royal Purple Ice

6 November 2006
Austin, TX
Need to decide between the two and best application strategy.

I know they are both good, but I have heard that WW causes brown stuff in your coolant and that just doesn't sound good. If Royal Purple is just as effective without that sideeffect, seems like a no brainer..

Also - 50/50 is the universal coolant and will protect to virtually near absolute zero (not really, but you get my point). However, it seems to me that a 60/40 solution upto a 70/30 for areas like Seattle where it does get a few degrees under 30F... but not by much, should be ok. I've also heard - and tested (not on tthe NSX..)- that because the coolant is under pressure, running straight watter will not freeze even a few degrees under 30F.

Water is after all, a much better heat transfer property than glycol.
Lastly - anyone try RMI-25 as a cleaner in their NSX?

Thoughts appreciated.
Water-wetter has always worked great for me. Some consider it the 'standard'.

I've had terrible luck with Purple Ice. I had great luck with their oils, but no-no-bueno on their coolant additive (well, radiator water additive).

"The Purple ice made a residue on everything including the paint and it wouldnt come off. Also it eats the aluminum in the radiators."

-From the crew chief on a race team that used it that I drove for.
Has anyone experienced "gunk" in their coolant tank after putting in Water Wetter in the NSX? I know this has happened on the S2000.. and some other cars.

My brother did a coolant change on hs E36 M3 and now there is what appears to be "oil/brown slimy gunk" in the coolant tank. We can't figure out if it's a headgasket ir if it's the consequence of water wetter. Car was never over-heated etc...

In any case, if it is Watter Wetter and it happens on the NSX too, I'm not putting that stuff in there.

PS: Anyone ever try a product called RMI-25? It's old, and supposedly works well with Alluminum. I haven't heard anything bad about it.. but also no one used it on the NSX..
Ive seen that happen on a Bimmer before -for that particular car it was the head gasket. Have him do a leakdown test.

I've never had that problem with water wetter. Make sure to always use distilled water. If you don't using water wetter + non-distilled water will show more gunk and deposits than if you used distilled water.

Ive never had a problem with WW in everything from gokarts->formula cars->sports cars and street cars.