Zerex G-05

[Michael J.]

I am ready to do the winter changing of coolant in my '66 L79 and '67 L71 and have heard this Zerex is the way to go. I bought it at the local NAPA store and the cover on the bottles says it is for most every car, except GM cars. I am assuming that is speaking about new ones, not old ones, but before I go through all that trouble I wanted to be sure it is OK to use in my cars. Thanks.

[Duke W.]

Re: Zerex G-05

GM recommends DexCool for their late model cars going back to circa 1996, but there is some question as to how well it protects solder. Late model cars don't have soldered radiators or heater cords.

G-05 is as close to a "universal antifreeze" as you can get, today. It's an HOAT formulation that provides excellent corrosion protection for all cooling system materials - vintage or modern.

There is lot's of information in the archives if you want all the whys and wherefores.

Duke

[Michael J.]

Re: Zerex G-05

Thanks Duke, I appreciate your views. I have looked through the archives, just wanted to make sure this current version of Zerex G-05 is the same as that discussed before.

[Timothy B.]

Re: Zerex G-05

Michael,

Also, go the the grocery store and buy a few gallons of distilled water, it's mineral free so the system will be protected against salts and hard minerals.

[Michael J.]

Re: Zerex G-05

Michael,

Also, go the the grocery store and buy a few gallons of distilled water, it's mineral free so the system will be protected against salts and hard minerals.

Thanks, yes I use RO water from my house unit when I do this. One question, the capacity says 22 to 24 quarts for a 427 (without and with heater), but the last time I filled it it took a litle over 2 1/2 gallons. Maybe I didn't get all the old stuff out. Any ideas for making sure it is empty before you refill?

[Terry M.]

Re: Zerex G-05

Thanks, yes I use RO water from my house unit when I do this. One question, the capacity says 22 to 24 quarts for a 427 (without and with heater), but the last time I filled it it took a litle over 2 1/2 gallons. Maybe I didn't get all the old stuff out. Any ideas for making sure it is empty before you refill?

Bingo.

It is very difficult to get ALL the coolant out of a system. Opening the drain plugs in the cylinder case goes a long way, but some can be trapped in the heater and hoses also.

Thoroughly flush the system with tap water -- then what remains will be clean water. Add the required percentage of anti-freeze for your part of the country -- then add water of your choice to top off the system. Yes there will be a few minerals in the system, but flushing with demineralized water is a little bit hard to do.

[Michael J.]

Re: Zerex G-05

Bingo.

It is very difficult to get ALL the coolant out of a system. Opening the drain plugs in the cylinder case goes a long way, but some can be trapped in the heater and hoses also.

Thoroughly flush the system with tap water -- then what remains will be clean water. Add the required percentage of anti-freeze for your part of the country -- then add water of your choice to top off the system. Yes there will be a few minerals in the system, but flushing with demineralized water is a little bit hard to do.

Thanks, that is a good idea. I have not run the engine for a minute or two after draining what you can, wonder if that would help as the water pump could drive more out?

[Terry M.]

Re: Zerex G-05

Running the engine briefly will get some coolant out, but is not as good as removing the cylinder case drains. However, if the drain plugs have not been out they can be a real challenge to remove, and on some engines they are close enough to the engine mount to make removal while in the car next to impossible. If the coolant system has not been regularly serviced even removing the cylinder case drain plugs may not be effective. I have had to poke around inside the water jacket to release the coolant because there is so much rust and sludge built up on the bottom of the jacket. And we wonder why the engine runs hot after all these years?

[Ronald L.]

Re: Zerex G-05

In a short time period of that former life I had the job of weeding out the good coolant from bad and establishing quality control for GM suppliers. What is good for iron and copper brass was not for those early aluminum big blocks.
You have three forces here working on the system. #1 contamination, that old rust and crud that Terry mentions will kill the additives in the coolant designed to protect copper and aluminum in one day. You saw me write early this year that these additives in coolant and oil are like antioxidant vitamins for your car, they are.

#2 Heat eventually starts to break down the glycols and then you open yourself up to #1

#3 those anti corrosive additives even with a clean system don't last.

Now, Some of those after market coolants did not meet (nor did they have to meet) the GM specifications. With that in mind and a bit of laboratory analysis knowledge, In use the Prestone brand and change yearly.

[Joel T.]

Re: Zerex G-05

In a short time period of that former life I had the job of weeding out the good coolant from bad and establishing quality control for GM suppliers. What is good for iron and copper brass was not for those early aluminum big blocks.
You have three forces here working on the system. #1 contamination, that old rust and crud that Terry mentions will kill the additives in the coolant designed to protect copper and aluminum in one day. You saw me write early this year that these additives in coolant and oil are like antioxidant vitamins for your car, they are.

#2 Heat eventually starts to break down the glycols and then you open yourself up to #1

#3 those anti corrosive additives even with a clean system don't last.

Now, Some of those after market coolants did not meet (nor did they have to meet) the GM specifications. With that in mind and a bit of laboratory analysis knowledge, In use the Prestone brand and change yearly.

Separate but related question guys... How often should the coolant be changed?? Yearly, every other, etc..?

Thx,

Joel

[Duke W.]

Re: Zerex G-05

In use the Prestone brand and change yearly.

"Prestone" and other brands are offered in several different formulations to meet current OEM specs. So...

Current OEM change recommendations vary from 3 to 5 years with a mileage limit that collector cars are unlikely to ever see in normal service, so it becomes a time issue.

Duke

[Ronald L.]

Re: Zerex G-05

Joel,

Every year, cheap, insurance you are doing the best you can for the car.

You don't want to wait until the glycol has degraded, and or the anti-corrosive additives are used up. Worse, you won't know unless you have an analytic lab at your disposal.

[Dick W.]

Re: Zerex G-05

If you are using conventional ethelyene glycol, use a cooling system additive such as Nacol. It can be purchased from any HD truck dealer, from NAPA or Carquest, or online. NAPA and Carquest, it is a product from Wix.

It will keep a clean cooling system clean for many miles. I have seen 1,000,000 mile engines that the water jackets looked like fresh cast iron. Follow the instructions on the bottle, but add two the first treatment.

[Jim T.]

Re: Zerex G-05

Michael I just completed two weeks ago the ZEREX G-05 change in my 68 L79. Used distilled water after flushing with tap water.
Removed my block drain plugs to drain the tap water about 3 times. I drove my 68 between draining and refilling with tap water. Glad I did, the water pump weep hole started leaking the tap water so I installed a new water pump.
Each block side of my L79 held about 3 quarts of water/coolant when I measured the drain individually from each side. This was after the radiator was finished draining.
The draining of the block had debris that came out with the water.

[Ray G.]

Re: Zerex G-05

"Prestone" and other brands are offered in several different formulations to meet current OEM specs. So...

Current OEM change recommendations vary from 3 to 5 years with a mileage limit that collector cars are unlikely to ever see in normal service, so it becomes a time issue.

Duke

Hello;
Does a rarely driven 60s Corvette(5 miles a year) engine w/ conventional ethelyene glycol require changing every two years or will adding cooling system conditioner suffice?

Thanks.