A few days ago I was visiting a corvette owner who has a radiator repair shop. He encouraged me to remove the Dex Cool coolant out of my 96 LT1 and replace it with the green coolant. His reasoning was that the Dex Cool coolant deteriorates and causes numerous problems that GM knows about but because of their contract with the coolant manufacturer they are not saying anything about it. I am hesitant to remove the Dex Cool coolant. It seems to be working fine for me, but was wondering if anyone else has heard this or decided to switch to the green coolants?

 

http://www.wcpo.com/wcpo/localshows/.../20299ce7.html

Just do a search on Google for "dexcool problem" and you'll have lots of similar pages to read. I use the new Prestone Long-Life stuff, it's still green.

BTW, Dexcool and the "green stuff" do not like each other very much and should not be mixed. This is what might be causing so many people to complain about sludge in their coolant. If you do switch be sure to completely flush your coolant system.

 

Dexcool does not mix well with ethelyne glycol (green) and I'm not too sure that the so-called "universal" coolants are a good idea in spite of the fact they are touted as being safe to use with almost any other coolants. Some imports use very special coolants and they do not recommend mixing the universal stuff.

Dexcool doesn't like air in the system so it's important to not have any air bubbles in the system after a cooling system service. The C4 cooling system has bleed valves that are used to "burp" the system and insure that no air is trapped inside. The pressure cap should be also checked to insure that no air can get inside through the cap mating surface on the expansion tank.

As mentioned, you would have to do a very thorough flush to remove all traces of the Dexcool if you go to the green stuff. Dexcool does allow for longer coolant life between cooling system service. IMHO, you are better off with staying with the Dexcool. It really doesn't cost that much more than the green and there is less labor involved.

Hard to say where this guy got his information, but there is really nothing to worry about with the continued use of Dexcool. GM uses it in all of their product line and has for about 10 years so the stuff can't be all that bad. I still have the original Dexcool fill in my 99 Silverado; it's clean and the coolant test procedures show it is still very much servicable.

 

My mechanic switched my '94 from the green stuff to dexcool 3 years ago and so far so good. He claimed that he's done this for a bunch of customers with no complaints. He does do a very, very thorough flush of the entire system before the conversion. Since then I've kept a close eye on the condition of the coolant and have seen none of the negative issues that others talk about. I'll tell you one thing that I strongly believe - I won't leave any coolant in there for 5 years/50000 miles regardless of what the manufacturer claims. IMHO, the main problem with DexCool is that people adhere to the recomended maintenance and leave it in there way too long.

 

Keep the DexCool but don't keep it for 100,000 miles or whatever ridiculous service interval the factory recommends.

 

Well my 95 has the green stuff......... however my 1996 GMC Yukon came with Dexcool.

I did leave it in for 5 years and suffered no ill effects what-so-ever. During that time I lived in the mountains of upstate NY and we often saw winter temps of 10 - 15 below for weeks at a time as well as summer temps in excess of 90.

Two weeks ago I sold the vehicle with 132K on the odometer and it was in perfect running condition.

 

 

My wife and I each have a '91 L98. Both were changed over to DexCool in 1998. My '91 had gone 130,000 miles, my wife's 35,000 miles.

Last month I drained the DexCool out of both, including opening the radiator bottom drain and the drains on bothe sides of the block. Despite what others had promised, I had no sludge or rust deposits. I pulled the intakes on both and there was no electrolysis on the heads or intake. The DexCool worked good.