Dex Cool? Or Prestone? Help

DEX COOL OR PRESTONE? I'M ABOUT TO FLUSH MY SYSTEM AND IT HAS DEX COOL IN IT NOW. I HAVE HEARD ABOUT DEX COOL OVERHEATING AND SLUDGE PROBLEMS. MY CHEVY DEALER STAYS WHY WOULD I WANT TO REMOVE DEX COOL. MY MECHANIC SAYS TO REMOVE IT . WHICH IS BEST IN THE LONG RUN FOR THE ENGINE? I HAVE A 1996 MONTE CARLO LS V6 3100 WITH 58,000 MILES PLEASE HELP.
THANKS IN ADVANCE

While the debate will probably rage on for many more years on whether to stick with DexCool, or use another antifreeze, here are some suggestions. DexCool is fine to use as long as you keep an eye on your overflow tank to make sure the level of coolant stays where it should be. It is a good idea to change out the DexCool every 2 years or 30,000 miles along with a cooling system flush, disregarding the instructions on the sticker in your engine compartment stating it only needs replacement every 5 yrs/ 150,000 miles. And make sure your radiator cap is working properly by not letting air get inside of your cooling system as this has been found to cause the sludging and gelling of the coolant. It doesn't cost that much to replace it every so often, and could be considered "extra insurance" against radiator cap failure. IN the long run, it is up to the car owner to decide whether they want to continue to use DexCool. If properly maintained and regular replacement of the coolant is performed, there shouldn't be any problems. I continue to use it in my GM vehicles that it came in without any issues.

I recently flushed the coolant in my 99 chevy lumina LTZ (3.8L). My mechanic advised switching to the green stuff only if EVERY DROP of the Dex-cool was flushed away. I just stuck with Dex-cool. It only cost about $20 for what I needed and my mechanic flushed/filled it for $20. It's not too expensive.

I agree, DEX is fine coolant if you change it regularly. Thats the key.

Just wanted to add my two cents here. I cannot say whether Dexcool is good or bad, but it certainly did sludge in my car and I only had it serviced by the dealer and followed the recommended maintenance schedules. Also, there was a settlement from Dexcool involving the plastic intake manifold gaskets going bad. My wife dumped Prestone in my radiator not knowing that it requires Dexcool and that was 6 months ago. I've not had any problems and when I have the coolant flushed next time, I will switch to Prestone. It's way cheaper and I haven't heard of a single problem with Prestone users.

Part of the issue with Dex Cool sludging was the extended maintenance interval (5 yr/150K). The longer a coolant remains in a cooling system the more of a chance for it to become contaminated and sludge up. Things like air getting into the coolant system from a faulty radiator cap, or letting the level get down too far,bad intake gaskets , and the mixing of other non compatible coolants also can be blamed . I've run Dex Cool since it's introduction in the mid 1990's without any issues (other than a bad intake in on of my vans) and I started changing it out and putting fresh coolant in the system every 3 years or 40,000 miles. That was pretty much the change interval for the old green coolants that were regularly used prior to the introduction of these newer, extended life coolants. (Even GM had admitted that the original 5/150 was too long a duration , and for awhile new cars did not have those little stickers claiming the 5/150 duration of their coolant.) If you plan on switching to Prestone make sure it's the grey jug and not the yellow one.

I really not worried about freeze or heat, it's mixed metals and rust protection!

See http://www.jaguarforums.com/forum/showthread.php?t=27533

Have you ever seen a galvanized freeze plug rust on a alum block, behind the transmission?

It's $3.5k for a Jaguar fix.