Hi Al, The actual Dex-Cool (which is no longer available) will do in any rubber seals in the engine, for sure. I have a Chevrolet with a 3.1 V-6 and at 60,000 had to replace the rubber intake manifold seals. When I got it apart there was not much left of them. I use the Prestone "Dex-Cool Approved" antifreeze now and have had no problems. ( in my old van, too) There is a class action lawsuit going on right now, I understand against the manufacturer of Dex-Cool. There is a service bullitin from GM to replace the Dex-Cool with an approved anti-freeze, so it is no myth. As long as you aren't running actual Dex-Cool, you'll be fine. Fred





At 08:04 AM 7/25/2006 -0700, you wrote:

I came across this statement on a web site discussing cooling issues with RX-7s:
 
Use a 30/70 mixture of ethylene glycol and water. Never use "red" coolant (Dex-Cool) as it is very corrosive to the seals inside the rotary engine.
 
I am using about a 30/70 mix of Prestone ?Dex-Cool Approved? and water.  From what I read, Dex-Cool was formulated by GM engineers specifically to give improved cooling and better corrosion protection for aluminum radiators.  I have two custom aluminum radiators in my airplane, along with some aluminum housings in the engine.  Seemed to me the Dex-Cool formulation was clearly the way to go.
 
Is the above statement just some bogus statement based on myth, or does somebody on this list have some data/experience to support it.
 
I?ve also been using this stuff in my old van and XJS for years with no issues.
 
Al