Changed My 8 Yr Old Dexcool Out.

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I replaced my FF in 2011, when it was 5 yrs old. This time I went longer at 8 yrs. This time I drained the rad and pulled block drain on the driver side, the pass side drain was blocked by the starter. In 2011 I did the same thing but also did a distilled water flush. This time I did not bother with the flush.

I had been waiting for a coolant related issue, like a water pump or stat, to drain the system but have not had any issues. After 8 yrs I did not feel comfortable leaving the old coolant in any longer. The GM recommended interval is 5 yrs. The coolant appeared to be in fine shape with no discoloration or deposits. The system capacity is 13l and I drained out 11l, so I drained out about 85%.

I used what I had in my stash, which was 2l of Prestone Dexcool concentrate from 2013 and a gallon of Prestone AMAM concentrate from this year, the rest being distilled water from Walmart.

AMAM looks more yellow when poured from the bottle but looks green in the surge tank. I did not bother premixing the concentrate. I just read the AGCO article emphasizing premixing but I really do not think it is an issue. FWIW I poured the distilled water in first and then the concentrate.
 
Not a good idea doing that. That juice will still be fine for cooling at 8 years . It's the additive package that breaks down then there may as I say be tears. I recall back in the dawn of that new age hearing all about the 💩 newer 5.3 engines . How they were eating head gaskets and whatever else it was almost cheaper to get another mill than fix, stuff like that. Couldn't figure it out at the time.
Then out came the big Dexcool " lifetime coolant" debacle. It all became clear. Google up the pics of the munchfest that can happen . Headgaskets looking like black shriveled Swiss cheese and such. Then there's the worm tracking on the mating portions of the casting. That will truly leave you kicking yourself
It can be anything from an inconvenience to a total disaster. Having once bought a yard engine (Honda)that someone had never changed the coolant in I can say just don't go there. I tried every trick known to man to make minehold a gasket right down to a JB weld filler 🤨, almost ,and cutting down a piece of plate glass and gluing 220 sandpaper and giving it an in car head planing . Nothing...© worked ! I swapped that head gasket ever 10000 almost right on schedule consistently. Luckily it was easy but still, IT SUCKS, especially in winter.
Seriously, back then there weren't so many diverse alloys all mixed together like today in an engine. Today there a regular potpourri of all sorts of dissimilar things. It's bad enough getting put through this sort of thing by the luck of the draw like me. I'd rather that though than be the guy saying i did it to myself. And for what to save a couple bucks and an hour or so, not me. I even quit mixing my own water and coolant. Well water with lime and calcium . No thanks I'll pay the extra $2 for their filtered deionized stuff.
 
I don't think the mixing of Dex-Cool and Prestone Cor-Guard hurt anything, the OAT component is the same between the two, Cor-Guard adds on phosphate and another inhibitor. I would have preferred all Dex or all Prestone but in this case since the two are compatible no harm done.

The LSx-based Vortec engines, compared to the 1996-2000 4.3/5.7/7.4 engines were designed to handle Dex from the start. There's a user here that never touches the cooling system on the fleet he manages unless there's a cooling system repair. Dex is actually a good coolant in systems that were designed for it from the start.
 
George7941, sounds like you are good for another 5 years.
thumbsup2.gif


Originally Posted by atikovi
What is FF? Or AMAM?


Factory fill / all makes all models.
 
Originally Posted by JLTD
George7941, sounds like you are good for another 5 years.

I hope that the current fill will be good for another seven years because my plan was to keep the truck for twenty years when I bought it. I will not be doing any more coolant changes on the truck unless I have to drain the coolant for a cooling system repair.
 
Still have the same Dex cool in my 2004 Cavalier that it came with IN 2004...granted, the car is low mileage.

Started the car yesterday and ran in 5 min to look everything over....everything still looks good.

That said-it's getting changed before winter.........
 
I have use the kind that works on all makes and models with no harm done for several years. I like to change it every 2 or 3 years but only a radiator drain and refill and never had a problem.
 
Originally Posted by Driz
Not a good idea doing that. That juice will still be fine for cooling at 8 years . It's the additive package that breaks down then there may as I say be tears. I recall back in the dawn of that new age hearing all about the 💩 newer 5.3 engines . How they were eating head gaskets and whatever else it was almost cheaper to get another mill than fix, stuff like that. Couldn't figure it out at the time.
Then out came the big Dexcool " lifetime coolant" debacle. It all became clear. Google up the pics of the munchfest that can happen . Headgaskets looking like black shriveled Swiss cheese and such. Then there's the worm tracking on the mating portions of the casting. That will truly leave you kicking yourself
It can be anything from an inconvenience to a total disaster. Having once bought a yard engine (Honda)that someone had never changed the coolant in I can say just don't go there. I tried every trick known to man to make minehold a gasket right down to a JB weld filler 🤨, almost ,and cutting down a piece of plate glass and gluing 220 sandpaper and giving it an in car head planing . Nothing...© worked ! I swapped that head gasket ever 10000 almost right on schedule consistently. Luckily it was easy but still, IT SUCKS, especially in winter.
Seriously, back then there weren't so many diverse alloys all mixed together like today in an engine. Today there a regular potpourri of all sorts of dissimilar things. It's bad enough getting put through this sort of thing by the luck of the draw like me. I'd rather that though than be the guy saying i did it to myself. And for what to save a couple bucks and an hour or so, not me. I even quit mixing my own water and coolant. Well water with lime and calcium . No thanks I'll pay the extra $2 for their filtered deionized stuff.



Biggest load of manure sprouted about DEXCOOL. It is NOT dexcool fault also as I worked/work on vehicles that use this coolant. SMH!!
 
Originally Posted by nthach
I don't think the mixing of Dex-Cool and Prestone Cor-Guard hurt anything, the OAT component is the same between the two, Cor-Guard adds on phosphate and another inhibitor. I would have preferred all Dex or all Prestone but in this case since the two are compatible no harm done.

The LSx-based Vortec engines, compared to the 1996-2000 4.3/5.7/7.4 engines were designed to handle Dex from the start. There's a user here that never touches the cooling system on the fleet he manages unless there's a cooling system repair. Dex is actually a good coolant in systems that were designed for it from the start.



That user would be me perhaps.


All our work vehicles are Dex factory equipped. Never any issues, and frequently go 200k before requiring any cooling system service at all.


The Dex hooey will likely last as long as the Fram garbage talk. Some of us never update...
 
Dexcool works fine in cooling systems designed for it, or that were designed for 2-Eha containing coolants.
It can be disastrous in older soldered radiator cooling systems for example though.
 
I don't have an issue with dexcool...haven't seen any problems with it since the late 90's/early 2000's, but I wouldn't mix it with another coolant, even if it was the same manufacturer. And I don't know if it matters or not, but I don't know what the shelf life for coolant is...I'm not sure putting coolant that's been sitting on a shelf for six years is ok, is it? I too have a gallon of dexcool sitting in my garage, but if it's six years old, how much longer will it be good for? Two years? You figure if you're going to put six year old coolant in your car, you really only have a couple years of service life left in it, no? I guess I'm being picky, it probably could go another 4, maybe more, but who knows? But if you go through the trouble of changing out a fluid that's supposed to last a long time, I'd want to do it with stuff that is newer/new, that way I wouldn't have to worry about it.
 
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