Steve, I just replied to this thread in the detailing forum. If I recall right, the parts guy at my local dealer, Knopf Automotive in Allentown PA, was not sure about what Winterwash was either.

I think the Summerwash may contain enough surfactants to work alone with a water mix, but I could be wrong. Since I live in an area that has subfreezing temperatures several months of the year, freezing is an issue for me. Actually I just let my independent garage fill my reservoir with Wurth brand fluid. Smells nice too

Has anyone recently used the concentrated stuff that GM used to recommend? I guess my only real concern / question would be how much alcohol or whatever antifreeze agent is in a winter concentrate, vs the cheapie generic washer fluid.

Perhaps a chemistry gury could chime in here? Somehow my hunch is that it would take roughly a pint of alcohol to reduce the freezing temp of a gallon of water to -20F, but I've been wrong before. Thoughts?

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Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic