my '98z has 39,600 miles and i've never flushed the radiator.

i was going to today, but my friend says the dex will last and last.

i bought some today and it says on the container "5 years or 150,000 miles" guaranteed.

is it a waste of money to flush mine anyway?

i've been on this board for over 2 yrs and have never heard anyone complain that leaving dexcool in hurt their radiator, etc...

 

you've got a '98? Then the stuff has been in there for 5 years.

Flushing won't hurt anything.

 

Doh! Thanks for pointing that out

Yeah, I guess it's time to flush the system. Thanks for the reply!

 

.... and the Delco battery will last 15 years !!

 

Too funny! About the Dex-Cool....it is cheap insurance. I just dump it every other year and refill. Why not?

 

I'm kind of skeptical about Dex-Cool.

My car has 41K miles on it and haven't changed the coolant yet, but the radiator dipstick is lightly coated with brown residue, which I'm hoping is not rust.

On the other hand, my brother's Sonoma with 26K miles has Dex-Cool and his system seems extremely clean.

Would it hurt to just do a good flush and use Prestone instead of Dex-Cool, or do new GM engines require Dex-Cool?

Also, are there any special procedures for changing the LS1's coolant? Do any breather valves need to be opened, or do you just drain it all out, flush with water and fill with coolant?

 

Before replacing the dexcool with prestone you'd better check the owner's manual and also check with local dealership service dept.

I know you are not supposed to mix the two (dexcool & prestone). You never really get all of the old coolant out of the system when you flush so there will probably be some dexcool left after flushing. If you refill it with prestone, then you'll be mixing dexcool & prestone (a no-no).

I don't think dexcool is a bad product I just don't think it should be trusted for 150k miles. My rule of thumb is to flush every 50-60k miles or every other year, whichever comes first. I always go back with dexcool and have never had a problem.

 

In my experience DO NOT run anything other then dex-cool. I completly flushed my 94 out at about 80,000 miles and put in Prestone. By 90,000 miles I had to replace some of the coolent pipe. By 135,000 I had to replace every peice in the car that had to do with the Coolent. Including, Radiator, waterpump, freeze plug, most hoses, and some of this had to be replaced 3 times. I would keep what came from the factory. I think it would have saved me some headaches and wallet aches.

 

I would be skeptical of the 150k miles claim. In our area there is a mechanic that has a talk show on a local radio station and when he talks about dex-cool he says not to trust it for that long. He points out that the radiator needs to be topped off so no air is in the system, will lead to a gelling effect of the coolant from air in the system. Says he has seen this many times. Also recommends flushing every 50k miles, or something like that. Just what I have heard. Also, to not mix dex-cool and prestone.

 

I have talked to the service depts. at 2 GM dealers in my area and neither like the dex cool.One guy even told me the best thing I could do is drain it,flush it out super good or have a pofessional do it,and replace it with reg anti-freeze.He said if keep using dex cool to flush it every 50,000 mi or 4-5 yrs max.If you don't it will gel up and then you'll need to replace your radiator and heater core,also mixing the 2 types of anti-freeze is also very bad.Hope this helps.

 

I, for one, dont trust any of those "will last for xx,xxx" miles. Like the new LS1 that says if you drive only on the highway that you dont need to change your oil for 10 or 15k miles, or something like that. I find that hard to follow when I pull the dipstick after 5k of highway and the oil is blacker than night. I say just change it anyway, since it has been 5 yrs for you, and just pay attention to it, and when it starts to get brown or changes color, just flush the system and change it again. It nevers hurts to be overly causious on these things.

 

I thought both Prestone and Havoline made a type of Dex-cool coolant (pink stuff). I understand that Dex-cool is the GM name, but these two companies both make a similar product, if not exactly the same.

I know you're not supposed to mix the pink stuff with the green stuff. Is this what y'all are talking about?

 

Why not just get the little antifreeze tester from the aprts store and see it has lost its usefullness? I'm talking about the one with little plastic ***** in an eye dropper with a flexible tube on the end.

My service dept also said that if air gets in the cooling system it will cause Dex-Cool to gell up. Be sure to keep those reservoirs full guys.

 

I would recommend flushing your car when it is 3-4 years old. Dex is ok but it does break down & it's additives can collect up in a form of a crusty substance. The trick is to get it out before it does this. I've pulled apart many dex-cool -unmaintained engines & the stuff can crust up pretty bad. But I still wouldn't take the chance & run anthing else in my LS1.

 

I was in Wal-Mart last night and saw a Prestone coolant that is "Dex-Cool approved". It's in a silver bottle with a light orange cap. Is it fine to use this or do we have to buy the real Dex-Cool from the GM dealership?