Dexcool does contain an additive to help lubricate the water pump seals to help them last longer, Mixing coolants is not good. They make owners manuals for a reason. There are several antifreeze types out there and lots of different types of lubricants that should not be mixed. So people who don't bother to read them and follow them get what they get.

 

I worked with Fords for about 18 years I know I should not say this on this site but I own a 2003 blazer and a 2000 Jimmy which I love very. Fords had a equivalent coolant to the DEX-COOL with the OAT anti -corrosive and they only had it a few years before they eliminated it because they were having multipule head gasket issues. Now I bought my son a 1997 Jimmy and he hit a tree and bent the frame. Now the people I bought this vehicle from took good care of it and gave me the records to prove it. They owned the vehicle since it was new and it was pasted through the family a few times and looking at the records they had it flushed one time and when I got it ,it had 150,000 on it but like I said my son bent the frame on it so that is how I got the 2000 jimmy. I know I am rambling on so I will get to the point (THANK GOD). I pulled the motor took it apart put a lot of new parts on it and the cooling system and passage looked perfect not one bit of sludge or corrsion in the motor so I will have to agree with swarth if you take care of them and do some maintenance I don't think you are going to have a problem but that is just my story.

 

I had an 04 Trailblazer with Dex-Cool & I traded it off at 80,000 miles with no cooling system issues.
My 97 Blazer was switched over before I bought it. But I have had no issues with it either. There is a very small amount of scum on the side of the overflow tank. But 60,000 miles it has run great.
I'm looking at a 98 Lumina LTZ tomorrow & the cooling system will possibly make or break a sale. That is one of the to check items.

 

Bad words cannot express how I feel about Dexcool...

 

I never had problems with DexCool in my '99 Suburban 454, until my truck hit 150,000 miles, then everything fell apart, ive replaced the radiator, intake gaskets, water pump, most of the hoses, and flushed everything. Im a little worried about the head gaskets, but everything seems to be ok. No more dex cool for me.

 

How often did you check the condition of the coolant and how often was it changed?

 

I changed it every year in the spring, same time I have the trans fluid and filter changed, I also have the transfer case and differentials changed. I never really had a problem, I figured regular maintenance would prevent the problems everyone else had, I was wrong. I learned my lesson about Dexcool. It was like clockwork at 150K the water pump started leaking, so i changed it, then the intake gaskets started leaking, when I took it apart it had just simply eaten the soft part of the gaskets up. Drove it one day and then the radiator started leaking where the plastic tank seals to the core, (dont know if dexcool caused that, but I blame it on it too. LOL) Oh well. All I have to say is change out the dexcool with green and never go back.

 

and then change all your gaskets again. They are designed for dexcool. So is the water pump, the green stuff doesnt offer the lubrication properties that dexcool does. So around 250,000 miles youll be replacing the water pump and everything else again.

 

What did the coolant look like. If you changed it every year I would expect it to look pink. It is not uncommon for water pumps & radiators to leak after that many miles with any coolant. The gaskets would likely have gone bad with any coolant.

 

I prefer the green coolant, ive used it in everything i have owned for the last 29 years and have never had a problem.

i have worked in the parts dept for gm dealerships for around the last 24 years, when dexcool first came out it was insane how much it cost.

and for years we had a majority of our service customers change back to the green when it was time for there first major service "60k"