Not a good idea at all. Most of the orange colored antifreezes are DexCool - a product GM used. It does not have a good reputation at all - do a google search and you can read about class action suits brought against the manufacturer and GM. In particular it does not like to be mixed with other antifreezes. I'd stay away from Dex. If it's in the car, I'd do my best to drain, flush every bit of it out, and just put good ole Prestone in there, or the WalMart generic equivalent.
the orange coolant you mention is a "long life" coolant. ford has it too, think its yellow? the " long life recommendation is about 100,000 mile i believe. where the normal green stuff is about every 2 years. its not good to mix them, although it wont really do any damage but will mess up the additives.
your best bet is to just run the green stuff. i dont trust a coolant that says it can go that long myself.
legomaniac - do a bit more research and you'll find there's a good body of evidence out there that points to some real problems with goo-ey deposits clogging things up internally leading to severe overheating problems that stems from mixing of the long life product with traditional antifreezes - at least the Dex (orange) product. Your comment that it really won't do any damage isn't an opinion that is shared by those who have struggled trying to clean up systems where the two were mixed. There's also a good body of evidence where people who simply left the Dex in for a long time also had problems with deposits inside the system - and overheating, head gaskets, clogged radiators seem to be the main symptoms. Where there's smoke, there's usually fire - best to stay away from the orange stuff. Don't know about Ford's version - but I think I'll just keep changing out my Prestone/distilled water every 2 years.
The last link tells GM/Texaco's side of the story -- they claim the problems arise from contamination (mixing), so it's not their fault. Consumers/lawyers claim they should've known that mixing would occur and to produce a product that won't work in those circumstances was negligent on their part. Either way, I'd stay away. Only took me the better part of a day and about 30 gallons of distilled water to get mine clean enough that I felt like I could put regular antifreeze back in. Ran the Dex for about 8 months - no noticeable issues with it during that time.
i read the links and if you read my post i did say that i wouldnt use the longlife myself either.
there are more that dexcool brands of longlife out there, one for mopar, volvo, and ford. but its only dexcool you hear problems from. so i would assume that its their product.
i work in a garage and we have found in our experience and from talking to other service people, most of the time the problem starts when the level is low. im not sure i believe it but we have been told that if the level is down, it causes air pockets in the system, which causes contamination of the fluid. IE: bad cap. some people dont realize that even though the fluid is "supposed" to be good for 150,000 miles or so..the cap and other stuff isnt.
have you found any bad news on the ford coolant? i havent read up on it much myself yet. even so..i still would stick with the green stuff.
anyway..the links were interesting
Dex is the only one I've read about all the problems with; don't know about the others. As with most systems, the key seems to be keeping the fluids clean/regularly changed. And to simply stay away from Dex until/unless they can determine with some certainty what the issues really are.