Exact Antifreeze Brand

[ZR1Vette]

Probably to add to the coldrum... in my research and in many discussions with ZR-1 owners and a certified LT5 tech went with Prestone Extended Life 50/50 (thus no issue on what water to use for full concentrate coolant ) Coolant...meets the GM 1825-M and exceeds ASTM D3306:
The coolants governed by this specification are categorized as follows:

Coolant TypeDescriptionIEthylene glycol base concentrateIIPropylene glycol base concentrateIIIEthylene glycol predilute (50 vol %)IVPropylene glycol predilute (50 vol %)
and ASTM D4985:
Covers the requirements for low silicate ethylene glycol base engine coolants

and the Prestone Extended Life has NO Silicate, phosphate, borate, and nitrate. Specifically recommended for aluminum block/head engines. Stuff is a little pricey compared to what else is on the market...but $$ is all relative.

[scottfab]

I had a gallon of milk go bad the other day..... Looked great but was still bad
Not sure if looks of green or orange are definitive. I have used looks on Dexcool up till now thinking if there is no sign of sludge then…ok. Now I am not sure. If the orange stuff turn acidic over it’s design life in the LT5 then maybe eating of the head gasket is possible.

I am amazed that one would ever leave green or orange stuff in a car for 15 yrs.
I don’t know of any fluid that would last that long in the LT5.
Being objective though, I think the orange stuff is suppose to last longer, like 5yrs
or so. The green stuff forms tiny crystals in it when it gets old. These take out the water pump. The orange stuff forms a nasty growth in it (sludge) if it gets contaminated
(or maybe old too?). The recent conjecture is that it eats (dissolves) the head gaskets
in the LT5. If actually true then I'll be getting off the Dexcool. If not provable then I'll stay with it and eat my burgers at Burgerville. Others can stay with green McBurgers.
Still others can stay with clear water and “water wetter” and eat at Wendy’s.

[jonszr1]

scott , you might also want to contact mark haibeck. he does alot of deep reasearch into things like this . he might be the best person to find the truth or lack of on the dexcool issue .you can find his web page by going to the links sec of the registry . hope this helps .

[scottfab]

Thanks for the lead.
I checked Mark's site. I only found how to fill and details on what his shop performs on a routine maintenance.
http://www.zr1specialist.com/HAT%20W...%20coolant.htm
http://www.zr1specialist.com/HAT%20Web/services/pm.htm
I wrote him a note on this topic.

[Z51JEFF]

I just flushed mine,used the Napa stuff,all I needed to see was the 1825 spec,good enough for me.As far as the Dexcool being a problem,all I needed to hear was head gasket failure and that did it for me.Is Dexcool bad for the system?I cant speak from experience but I wont put it in my car.

[tomtom72]

FWIW, the only time I saw a thread about antifreeze and head gasket failures with pictures was over at CF in the ZR-1 section. The author of the thread was "MrCrowley", aka Mike Ebert of EES (Ebert's Engine Service, EES.com). He started the thread to show us what the failure looks like. If I remember correctly it was an issue with the gasket material being delaminated from the exposure to the newer generation of Organic Acid Bassed coolants.

A search over there may turn up the thread, but I've heard that the archives were toated when they got new servers.


Tom

[Aurora40]

Originally Posted by ZR1Vette

and the Prestone Extended Life has NO Silicate, phosphate, borate, and nitrate.

This is because it is an OAT type coolant just like DexCool. The fact that it has no silicates is not, in my opinion, a good thing.

I really don't see the point with going with something other than a proven/recommended silicated anti-freeze. The longer change intervals of DexCool don't really apply if you are putting it into a system that already has silicates in it. I don't think even a flush would work because the silicates stick to stuff (which is how they work, apparently). So with DexCool you'd want to stick with conventional change intervals anyway.

Unless you are trying to go with more water % with something like water wetter, why not just make the safe play with silicated coolant. It works great, I'm not aware of any downsides other than it becoming harder to find and a bit pricier.

Lately I've actually thought of going to something "friendly" like Sierra or something. Mainly because they are a traditional silicated coolant and are cheap. Plus I won't be as worried about small leaks, etc. The only difference is they are propylene glycol vs ethylene glycol. It apparently transfers heat slightly less efficiently (though water does the bulk of that), but is factors of 10 less toxic.

[ZR1Vette]

Bob.. I am willing to look at all views and learn... this coolant issue is confusing at best. To wit... GM 1825-M notes no silicates "GM says getting rid of traditional silicates helps to extend the life of the water pump" and " ethylene glycol antifreeze that contain a corrosion inhibiting chemistry that uses carboxylate organic acids instead of the silicates, phosphates or borates"

Thus when I talked to the Prestone tech folks this is what the Prestone Extended Life coolant does (I just used the 50/50 mix from them to eliminate the issue of what water additive is used)

If I am going down an incorrect road folks... let me know.

[jonszr1]

so if i am reading you right you changed over to the new stuff . one ? how well did you flush the system before putting in the new stuff .i have heard that problems can develope if you dont flush the system really really well. did the presone people share that with you. did you ask about potental problems in changing over ?

[Aurora40]

Originally Posted by ZR1Vette

Bob.. I am willing to look at all views and learn... this coolant issue is confusing at best. To wit... GM 1825-M notes no silicates "GM says getting rid of traditional silicates helps to extend the life of the water pump" and " ethylene glycol antifreeze that contain a corrosion inhibiting chemistry that uses carboxylate organic acids instead of the silicates, phosphates or borates"

What are those quotes from? The actual GM 1825M spec? The coolant listed in your FSM, #1052753, is a silicated ethylene glycol coolant. They were called "low silicate" formulas back then, but are definitely of the silicated variety. Not an OAT coolant.

Also if I'm not mistaken, Prestone's Extended Life coolant does not meet the GM-1825M spec. I believe only their "regular" coolant does, though I don't know if you can even find it anymore.

I also could be wrong, but I do not believe GM has ever recommended using DexCool in a vehicle that was not designed/originally filled with it.