I have read past threads recommending Zerex G-05 for C2 and C3 Corvettes. I have also read articles saying that extended life anti-freeze with organic acid technology (OAT) like Dexcool is bad for copper/brass/solder. Zerex G-05 uses "hybrid" organic acid technology (HOAT). What is the difference between OAT and HOAT antifreeze? Is this difference great enough to bet our copper radiators on?
Zerex G-05
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Re: Zerex G-05
Zerex G-05 is the best stuff to use for our older cars. It is also good for new cars as well. Mercedes has been using it for over 25 years in all their cars. Also Chrysler and Ford. It protects cast iron, steel, copper, aluminum, and lead solder joints in our old heater cores.
Prestone yellow is also very good.
Just pick one.
Larry
EDIT: For what it's worth, I have been using G-05 in my 1967 car for over 20 years without any issues. I have also run volt potential measurements on my cooling system using a Fluke multimeter and the results are VERY GOOD.- Top
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Re: Zerex G-05
Patrick;
I had the exact same question last year when I changed the coolant in my 65' 365hp, with 411 gears out back. Everyone that chimed in at the time recommended the Zerex G-05 (I used the premixed blend). In my case, it's an aluminum radiator. Since that coolant change, my car runs at 175 degrees in normal driving, and goes up to 185 when I'm at a red light....very happy ! My thermostats is a 180 degree unit & I'm running the car with the Rotella 15-40 weight mineral oil. It's all good. David- Top
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Re: Zerex G-05
I have read past threads recommending Zerex G-05 for C2 and C3 Corvettes. I have also read articles saying that extended life anti-freeze with organic acid technology (OAT) like Dexcool is bad for copper/brass/solder. Zerex G-05 uses "hybrid" organic acid technology (HOAT). What is the difference between OAT and HOAT antifreeze? Is this difference great enough to bet our copper radiators on?
Patrick-------
It's like this:
For cars with aluminum radiators and copper/brass heater cores Zerex G-05 is best
For cars with copper/brass radiators and copper brass heater cores Zerex G-05 is best
The above configurations include ALL 1953-96 Corvettes
For cars with aluminum radiators and aluminum heater cores Dexcool is best.
The above configuration includes all 1997-2015 Corvettes.In Appreciation of John Hinckley- Top
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Re: Zerex G-05
You guys sound pretty sure of this. The Zerex web site is much more circumspect. I found a section of it that gave raw numbers for weight loss of various metals in a corrosion test with G-05. The weight loss of brass and copper was more than for aluminum, but it gave no interpretation of what constituted a good score in this test.- Top
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Re: Zerex G-05
You guys sound pretty sure of this. The Zerex web site is much more circumspect. I found a section of it that gave raw numbers for weight loss of various metals in a corrosion test with G-05. The weight loss of brass and copper was more than for aluminum, but it gave no interpretation of what constituted a good score in this test.
No antifreeze/coolant is perfect…………..but G-05 is about the best out there. DEX-COOL is not nearly as good for our older cars. Duke wrote many a thread/article on this years ago. I also worked as an engineer for Union Carbide and (among other things) made the Prestone coolant when UCC still had the product.
The corrosion test info I have from Zerex G-05 shows:
Copper Weight loss of 2 versus ASTM spec of 20 (ASTM 2570 test….mg weight loss per specimen)
Lead solder Weight loss of 2 versus ASTM spec of 60
Steel Weight loss of -1 versus spec of 20
Aluminum Weight loss of -2 versus a spec of 60
These tests were service tests and not lab glassware tests. The glassware test results were better. Also, consider any negative number to represent zero loss.
If you don't trust G-05 then you need to find something better……………….and I haven't found it yet.
Prestone used to publish their corrosion specs and results, but after UCC sold the product rights, the new company refused to release the results. Yet I believe Presone yellow is a good/acceptable product as well. But I can't show you any data.
FWIW
Larry- Top
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Re: Zerex G-05
I have read past threads recommending Zerex G-05 for C2 and C3 Corvettes. I have also read articles saying that extended life anti-freeze with organic acid technology (OAT) like Dexcool is bad for copper/brass/solder. Zerex G-05 uses "hybrid" organic acid technology (HOAT). What is the difference between OAT and HOAT antifreeze? Is this difference great enough to bet our copper radiators on?
HOATs have been around for some time. What is called Zerex G-05 was developed by BASF in Germany over 30 years ago, and was used by Mercedes-Benz beginning in the early to mid-eighties. Chrysler switched to it as a result of the DB-Chrysler merger, and it's also used by Ford.
Z-05 is the new "universal antifreeze" that protects all metals that are found in cooling systems - both in new and vintage cars, and since it's low in inorganic salts, it's less likely to clog up radiator tubes than the high silicate "green" antifreeze of yore. These traditional antifreezes were good at protecting aluminum radiators, but when they clog up tubes with precipitated salts, aluminum radiators are just as dead as if they were leaking because clogged up tubes won't provide sufficient cooling.
Duke- Top
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Re: Zerex G-05
Just for the sake of conversation I just did total restore to include a 427/390 engine to match my car's original engine's specs. I am running a coolant (expensive) called Evans High Performance. No water, capable of running at higher temps with no boil over.- Top
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Re: Zerex G-05
Larry--- Thanks for the interpretation of the corrosion test. I'll be shopping for some G-05.- Top
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Re: Zerex G-05
Evans coolant has been discussed many times. It's straight propylene glycol. GM specfically says to NOT USE propylene glycol antifreeze.
I have no idea what type of corrosion inhibitor package it has, if any.
The problem with propylene glycol is that is has signficantly less heat capacity than a 50-50 mix of ethylene glycol and water, so operating temperatures are going to be higher, which is tougher on elastomers and promotes detonation. Sure, boilover temperature is a lot higher, but at that point you are frying all the elastomers and the engine is likely into heavy detonation.
IMO, it's pure snake oil.
Duke- Top
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Re: Zerex G-05
I get mine from NAPA, but many other stores carry it also.
You can also buy from Ford and Chrysler under their own part numbers. I can get these numbers if you need them, but the dealers will charge more $$ for the same product than NAPA and other auto parts stores.
You can buy as concentrate or as a 50/50 mix. If you get the concentrate (better $$ deal), then dilute using distilled or deionized water. Every grocery store in the land has distilled/deionized water for about $1 per gallon (or less).
Cooling system capacity for the C2-C3 cars is about 20 quarts or 5 gallons. A little less for SB and a a little more for the BB cars.
Larry- Top
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Re: Zerex G-05
Every grocery store in the land has distilled/deionized water for about $1 per gallon (or less).[/QUOTE]
Drug stores too.- Top
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Re: Zerex G-05
Oops - my bad - I meant to say G-05, not Z-05. The least expensive way is to buy the full strength type and mix it approx. 50-50 with distilled water.
Change it every five years - completely drain the system by opening the radiator drain cock and pulling the block drain plugs. Look at the owner's manual for your engine-heater configuration, add about half the stated capacity G-05, and top off with distilled water.
The capacity is for a completely empty system, and even pulling the drain plugs will leave some residual, so you will end up with about a 55 percent concentration of the G-05, and the target range is 50-60 percent.
Duke- Top
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Re: Zerex G-05
Evans coolant has been discussed many times. It's straight propylene glycol. GM specfically says to NOT USE propylene glycol antifreeze.
I have no idea what type of corrosion inhibitor package it has, if any.
The problem with propylene glycol is that is has signficantly less heat capacity than a 50-50 mix of ethylene glycol and water, so operating temperatures are going to be higher, which is tougher on elastomers and promotes detonation. Sure, boilover temperature is a lot higher, but at that point you are frying all the elastomers and the engine is likely into heavy detonation.
IMO, it's pure snake oil.
Duke
We had some Viper owners ready to go with the Evans stuff when we introduced the Gen II engine in 1996 (including their double and/or triple-pass radiators) based on reading the Evans marketing hype, and they asked us (Viper Engineering) the same questions; we already had the lab reports on propylene glycol tests, but we set up two Vipers with the Evans stuff, and they confirmed the lab expectations. Engine temps went up 15*-20*F. Ever since, the owner's manuals for Chrysler products have had a black-bordered warning in the cooling system section notifying the owner that use of propylene glycol coolant voids the engine warranty.- Top
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