replacement type of anti freeze?

[John M.]

It is Fall and time to begin winter storage routine. What is the procedure for changing from "green" to " universal" anti freeze. There is so much posted on here about the "HOAT?" and that it is more appropriate for our cars, that is seems like the thing to do. So, is a flush needed, is a fill with distilled water needed between the two types needed as well? Would love to hear how you did it and the results. Or, just your opinion on switching to this option. Thanks in advance!,

[Joe L.]

Re: replacement type of anti freeze?

It is Fall and time to begin winter storage routine. What is the procedure for changing from "green" to " universal" anti freeze. There is so much posted on here about the "HOAT?" and that it is more appropriate for our cars, that is seems like the thing to do. So, is a flush needed, is a fill with distilled water needed between the two types needed as well? Would love to hear how you did it and the results. Or, just your opinion on switching to this option. Thanks in advance!,

John------


Flushing the cooling system is always a good idea if the system has not been flushed in a long while. However, it's not required for simply changing from one type of coolant to another. The system does not have to be scrupulously purged of all traces of the existing coolant. In other words, it's not like changing from DOT 3 brake fluid to DOT 5 or vice-versa.

What you need to do is to be sure that all coolant is drained from the system. So, the block drains have to be opened and the radiator drained. One should do this even if one is not changing the coolant type. Then, simply re-fill the cooling system with the appropriate mix of coolant and distilled water. While the recommended mix is 50/50, I use a 60/40 mix of coolant to distilled water. For 1953-96 Corvettes I recommend Zerex G-05. This is the only HOAT coolant formulation I know of. It's really not dramatically better than the standard "green" coolants but it is a little easier on the solder joints of copper/brass radiators and heater cores. So, that's benefit enough that I now go with it.

The Zerex G-05 meets GM's specifications for all 1953-95 Corvettes. Technically, it does not meet the specifications for 1996 Corvettes since GM specified Dexcool for that and all subsequent model years. This is one of the rare cases in which I would deviate from GM specs. 1996 Corvettes use a cooling system basically identical with 1992-95 Corvettes, including a copper/brass heater core. So, if I owned a 1995 Corvette I would use Zerex G-05.

For 1997 and later Corvettes I recommend doing as GM specifies and use only Dexcool coolant.

[Michael J.]

Re: replacement type of anti freeze?

I would agree with all that Joe has said.

[Frank D.]

Re: replacement type of anti freeze?

You may find those block drains thwart you if they'be been in a while and/or over-tightened; if you can't get them out you'll have to decide if its worth it to get more aggressive or to do the flush without removing them. Ask me how I know (Ugh!)

As Joe said its not imperative to get every last vestige of the old anti-freeze out completely...

[Ed S.]

Re: replacement type of anti freeze?

You may find those block drains thwart you if they'be been in a while and/or over-tightened; if you can't get them out you'll have to decide if its worth it to get more aggressive or to do the flush without removing them. Ask me how I know (Ugh!)

As Joe said its not imperative to get every last vestige of the old anti-freeze out completely...

Yes - those block drain plugs are not easy to get to, and as Frank said, if they haven't been out in the last decade or so be prepared for a challenge. If you do try it I recommend putting a 6 point socket instead of a 12 point on it, less chance of rounding the plug. If you get them out and fluid does not flow just get a small screwdriver or a pointed object and push it into the threaded hole - fluid is not pouring out because the hole is clogged with gunk. Once you break the gunk it will flow freely. Consider buying new plugs if the old ones appear damaged - not expensive at all.

[Michael H.]

Re: replacement type of anti freeze?

John I use the Zerex G-05 in my 67.

Mike

[John M.]

Re: replacement type of anti freeze?

Thanks to all of you for a reply. Drained all the old "green A F", filled system with distilled water and ran until thermostat opened and engine get up to operating temp, drained that and filled with GO5 Zerex. 2 gal prediluted should get us through the winter but will check the protection after a little Sunday drive. I suppose that a standing floating ball anti freeze checker for the green fluid will work on the GO5 stuff?

[Joe L.]

Re: replacement type of anti freeze?

Thanks to all of you for a reply. Drained all the old "green A F", filled system with distilled water and ran until thermostat opened and engine get up to operating temp, drained that and filled with GO5 Zerex. 2 gal prediluted should get us through the winter but will check the protection after a little Sunday drive. I suppose that a standing floating ball anti freeze checker for the green fluid will work on the GO5 stuff?

John------


Did you open the block drains to drain the system?

[John M.]

Re: replacement type of anti freeze?

Yes, Joe. the drains came out with little problems but made a mess. I have been fighting an overheating problem for some time so the cooling system and drains were in very good shape from several changes of radiator fluid.

[John M.]

Re: replacement type of anti freeze?

These block drain plugs do double duty also as anti-knock sensors, or at least they do on my 1994 LT1. Instructions in the service manual state that there is a special sealant on these block plugs and to NOT put any other sealant such as compound or Teflon tape on these threads. There are wire leads that connect to each plug. I am hopefully going through the anti-freeze change process this week as it is overdue, so I will be revisiting the underside of OUR 94 C4 and these drain/anti-knock sensor plugs shortly when I get the car high enough to crawl under. In anything I can find on these plugs there is no recommendation that you should replace these plugs once removed, which leads me to believe that the special plug sealant must be reusable as is. Last time I changed anti-freeze I used the old plugs and torqued them to specs and they must have worked as there was no leaks. I use PEAK original green anti-freeze and dilute it with Reverse Osmosis (RO) water. I shy away from distilled water because depending on how it is distilled it is used for cleaning boilers. Boilers are flushed and filled with distilled water and run for a period and then flushed again. The distilled water minis its ions replaces the ions from wherever it can and in the process cleans the boiler insides. That means to me that inside an automotive cooling system this distilled water replaces its missing ions from the metal and solder joints it embraces. Something to think about.

Save the Wave ............ JGM

[Duke W.]

Re: replacement type of anti freeze?

I suppose that a standing floating ball anti freeze checker for the green fluid will work on the GO5 stuff?

Yes. G-05 like most antifreeze products is ethylene glycol based. The difference between IAT, OAT, and HOAT is the corrosion inhibitor chemistry.

Duke

[Duke W.]

Re: replacement type of anti freeze?

These block drain plugs do double duty also as anti-knock sensors, or at least they do on my 1994 LT1. Instructions in the service manual state that there is a special sealant on these block plugs and to NOT put any other sealant such as compound or Teflon tape on these threads. There are wire leads that connect to each plug. I am hopefully going through the anti-freeze change process this week as it is overdue, so I will be revisiting the underside of OUR 94 C4 and these drain/anti-knock sensor plugs shortly when I get the car high enough to crawl under. In anything I can find on these plugs there is no recommendation that you should replace these plugs once removed, which leads me to believe that the special plug sealant must be reusable as is. Last time I changed anti-freeze I used the old plugs and torqued them to specs and they must have worked as there was no leaks. I use PEAK original green anti-freeze and dilute it with Reverse Osmosis (RO) water. I shy away from distilled water because depending on how it is distilled it is used for cleaning boilers. Boilers are flushed and filled with distilled water and run for a period and then flushed again. The distilled water minis its ions replaces the ions from wherever it can and in the process cleans the boiler insides. That means to me that inside an automotive cooling system this distilled water replaces its missing ions from the metal and solder joints it embraces. Something to think about.

Save the Wave ............ JGM

Knocks sensors only date back to sometime in the nineties... not and issue with C1-early C4.

Any potable water is okay for a water flush. Distilled water isn't necessary for that, but it will do no harm for the short time it's in the system.

There's a lot of confusion about use of distilled water in cooling systems.

Straight domestic/distilled/deionized/RO water should NEVER be used in a cooling system, long term. The reason to blend distilled water with full strength antifreeze is to preclude the introduction of unwanted ions like Calcium and Chlorine (that may be in domestic water) to the cooling system that can degrade the corrosion inhibitor package.

Duke

[Dick W.]

Re: replacement type of anti freeze?

Here is an excerpt from a Chevron bulletin



What is a Coolant?




Water

Glycol (ethylene or propylene glycol) is added to water to withstand freezing temperatures and to raise the boiling point so that the engine stays cool during operation. Ethylene glycol is perhaps the most common because it has better heat exchange properties than propylene glycol, which is less toxic. Mixing the two glycols in the water can result in erroneous freeze point readings on a refractometer or hydrometer.


The Rainbow of Confusion


While the color of a coolant - red, orange, yellow, green, blue, purple, pink, etc., may denote a particular coolant type, there is no industry standard that manufacturers are required to follow when marketing their products. These colors are merely the result of a dye that is added to aid in identification and has no effect on quality or performance.


Finally, a chemical inhibitor, or additive package, is added to help prevent corrosion in the radiator, water pump and other internal cooling system components.


Coolant Types



Conventional Low-silicate

Fully-formulated

Extended Life Coolants (ELC)



Mixing Coolants



Conclusion

[Joe L.]

Re: replacement type of anti freeze?

Knocks sensors only date back to sometime in the nineties... not and issue with C1-early C4.

Any potable water is okay for a water flush. Distilled water isn't necessary for that, but it will do no harm for the short time it's in the system.

There's a lot of confusion about use of distilled water in cooling systems.

Straight domestic/distilled/deionized/RO water should NEVER be used in a cooling system, long term. The reason to blend distilled water with full strength antifreeze is to preclude the introduction of unwanted ions like Calcium and Chlorine (that may be in domestic water) to the cooling system that can degrade the corrosion inhibitor package.

Duke

Duke------


For Corvettes, knock sensors began with the 1982 model year.

[Joe L.]

Re: replacement type of anti freeze?

These block drain plugs do double duty also as anti-knock sensors, or at least they do on my 1994 LT1. Instructions in the service manual state that there is a special sealant on these block plugs and to NOT put any other sealant such as compound or Teflon tape on these threads. There are wire leads that connect to each plug. I am hopefully going through the anti-freeze change process this week as it is overdue, so I will be revisiting the underside of OUR 94 C4 and these drain/anti-knock sensor plugs shortly when I get the car high enough to crawl under. In anything I can find on these plugs there is no recommendation that you should replace these plugs once removed, which leads me to believe that the special plug sealant must be reusable as is. Last time I changed anti-freeze I used the old plugs and torqued them to specs and they must have worked as there was no leaks. I use PEAK original green anti-freeze and dilute it with Reverse Osmosis (RO) water. I shy away from distilled water because depending on how it is distilled it is used for cleaning boilers. Boilers are flushed and filled with distilled water and run for a period and then flushed again. The distilled water minis its ions replaces the ions from wherever it can and in the process cleans the boiler insides. That means to me that inside an automotive cooling system this distilled water replaces its missing ions from the metal and solder joints it embraces. Something to think about.

Save the Wave ............ JGM

John------


I've never had a leakage problem after re-installing knock sensors without the addition of any thread sealant. The thing that is most important is that the knock sensors not be over-torqued on installation. Follow the torque instructions in the factory service manual.

There is no significant difference between water purified by distillation, reverse osmosis, or de-ionization. None of these processes in any way changes or modifies the nature of the water. The only thing these processes do is to remove impurities in the water, primarily dissolved solids. The only thing that matters is the final total dissolved solids (TDS) content of the water, the lower the better regardless of which process is used.