What advantages does the Zerex G05 coolant really have?

[adventureboss]

I know that the owners manual for later TJs such as my 06 specifies the mopar HOAT stuff and a well liked product on this forum seems to be the Zerex G05 HOAT coolant. Why? I understand that it has a longer life and maybe better protection against corrosion, but does it have any other advantages? Any increase in cooling performance? Right now, I'm running the green Prestone All makes stuff just because it's easy to get and is cheap. I know Prestone says "10 years/ 300k miles" but I really don't know if I believe that, so mine gets changed out every 30k miles.

I'm considering switching over to the G05 but also the green stuff has been working fine so I wouldn't want to waste my time switching over if there's not much benefit.

 

[AndyG]

Surely someone out in that area can chime in- you guys see some heat.

 

[IOwnCalculus]

Zero benefits other than long life, and personally, I hate G05 because the dye is so faint it looks about the same as clean motor oil or brake fluid.

 

[LONGJP2]

I know that the owners manual for later TJs such as my 06 specifies the mopar HOAT stuff

Cheaper and more accessible than Mopar.

Is your green Prestone HOAT?

 

[adventureboss]

Surely someone out in that area can chime in- you guys see some heat.

definitely. The AC has a hard time keeping up when it's 110+ outside and I'm idling. So if this helps with that by reducing coolant temps I'll do it.

 

[adventureboss]

Zero benefits other than long life, and personally, I hate G05 because the dye is so faint it looks about the same as clean motor oil or brake fluid.

Hmm this isn't something I thought about.. I don't like that either. That might be a dealbreaker for me.

 

[adventureboss]

Cheaper and more accessible than Mopar.

Is your green Prestone HOAT?

Nope its some weird hybrid OAT, it's just the generic stuff you get at any autoparts store, prestone max I think?

 

[machoheadgames]

I switched from conventional green to G05 years ago. I perceived no tangible benefits and as stated, it was much harder to see compared to the green. I removed the motor for some other reasons and when I reinstalled it, fully dry, I went back with green. Keep the green refreshed every few years and I see no real reason to change. Especially if you have one of the years that calls for it. I don’t think there any real world cooling benefits at all, the system is already capable of overcooling with the green stuff.

I do believe you mean yours is an IAT, not OAT. Green is typically IAT and is compatible with HOAT but mixing removes the benefit of the HOAT lasting longer.

 

[IOwnCalculus]

Especially if you have one of the years that calls for it.

Worth noting there's zero difference in the cooling systems between '97-'01 TJs that came with classic green coolant and '02-'06 TJs that came with G05. It was a change DaimlerChrysler made across their entire lineup, not the result of anything in the vehicle that required it.

 

[machoheadgames]

Worth noting there's zero difference in the cooling systems between '97-'01 TJs that came with classic green coolant and '02-'06 TJs that came with G05. It was a change DaimlerChrysler made across their entire lineup, not the result of anything in the vehicle that required it.

I’m aware, I referenced the year range due to keeping it year specific vs mixing, for simplicity sake. If I had a year that called for HOAT, I’d use Mopar or Zerex just because it’s easier to stick to the book. With an older model I see no benefit to converting to the newer stuff, so on those especially, I elect for green. I wouldn’t convert a newer one backwards, but I now also see no reason to update an older one to the newer stuff.

 

[Zorba]

I'm "touchy" about coolant, mainly due to many years of running various European cars made out of European alloys, and seeing what happens when Green coolant fails to protect the system from corrosion. I'll only run what the MFG recommends, nothing else. Does it matter with a traditional cast iron American motor? Maybe not, I'm not a coolant expert by any means and I don't know how well Green protects the aluminum water pump, blah, blah. In other words, its cheap and easy enough to run the recommended stuff, so I do. YMMV and all that.

As an aside, the VERY first thing I look at on a used car is the radiator. I lift that cap and look. If it looks like crap, I figure the rest of the maintenance was neglected or done wrong as well, and I walk away.

 

[bucky]

I run Motorcraft yellow in my Fords mainly because I have an account at the local dealer and my discount brings the cost down to Walmart prices. Everything else gets Walmart extended life green. This allows me to avoid mixing different coolants. For my diesels I use anti-cavitation additive. I flush and change every 5 yrs. Always use distilled water even for the flush. I’ve had the occasional water pump replacement, blown hoses and fan clutches due to high miles or vehicle age. Never had to replace a radiator yet. Routinely get 300+K on my vehicles. My TJ temp stays the same fast, slow, 115 degres or AC on. Fan kicks on only when pushing it hard in the heat.
50/50, distilled water and timely changes have worked well for me in 50+ yrs of vehicle ownership. Never had the need to add a wetting agent to increase cooling.

 

[Zorba]

...For my diesels I use anti-cavitation additive. ...Never had the need to add a wetting agent to increase cooling.

I was under the impression that they were one and the same. I ran water wetter in my old F-250 diesel for that reason - and I now run it in everything as additional cooling doesn't hurt anything...

 

[bucky]

I was under the impression that they were one and the same. I ran water wetter in my old F-250 diesel for that reason - and I now run it in everything as additional cooling doesn't hurt anything...

Bottle says anti-cavitation. Looking at the ingredients it’s acidic and has several sodium compounds. My Powerstroke 7.3 and 6.7 call for it along with my Cummins ISL9. I use test strips every 6 months to keep the proper level and add as necessary. I think wetting agents are different.

 

[Zorba]

Bottle says anti-cavitation. Looking at the ingredients it’s acidic and has several sodium compounds. My Powerstroke 7.3 and 6.7 call for it along with my Cummins ISL9. I use test strips every 6 months to keep the proper level and add as necessary. I think wetting agents are different.

View attachment 572357

Yea, I sure don't know. Back in the day when I had a 6.9 IDI, we were told to run water wetter. *shrug* Probably was the best available at the time.

 

[Gilaguy23]

https://www.machinerylubrication.co...,silicates and inhibitors called carboxylates

Bored? read up on the endless coolant types of today.

 

[JKP]

I'm "touchy" about coolant, mainly due to many years of running various European cars made out of European alloys, and seeing what happens when Green coolant fails to protect the system from corrosion. I'll only run what the MFG recommends, nothing else. Does it matter with a traditional cast iron American motor? Maybe not, I'm not a coolant expert by any means and I don't know how well Green protects the aluminum water pump, blah, blah. In other words, its cheap and easy enough to run the recommended stuff, so I do. YMMV and all that.

As an aside, the VERY first thing I look at on a used car is the radiator. I lift that cap and look. If it looks like crap, I figure the rest of the maintenance was neglected or done wrong as well, and I walk away.

Green protected all the Fe and Al parts just fine when it was the recommended coolant in the 4.0.

I still have green in the YJ.

G05 protects all the Fe and Al just fine in the TJ.

I haven't seen any difference. And now Zerex claims the Original Green is 5 yr, 150k mi too.

Too lazy to completely flush one of them and consolidate.

 

[TJRick]

I'm "touchy" about coolant, mainly due to many years of running various European cars made out of European alloys, and seeing what happens when Green coolant fails to protect the system from corrosion. I'll only run what the MFG recommends, nothing else. Does it matter with a traditional cast iron American motor? Maybe not, I'm not a coolant expert by any means and I don't know how well Green protects the aluminum water pump, blah, blah. In other words, its cheap and easy enough to run the recommended stuff, so I do. YMMV and all that.

The cooling system did not change from 1997 - 2006.

The factory coolant for the early TJs used conventional green coolant.
The factory coolant for the later TJs used the HOAT orange coolant.

The orange (Valvoline) HOAT coolant claims protection for 5 years/150,000 miles.
The conventional green (Prestone) coolant also claims protection for 5 years/150,000 miles.

More than likely, the "corrosion" you have seen had less to do with the generic Prestone coolant and more to do with what type of water it was mixed with.


On a personal note, my 1998 Jeep TJ has had the green (Prestone) coolant in it it's entire life. I changed it out every 5 years and mixed it only with distilled water. My original water pump lasted 23 years before I had to replace it.

 

[Zorba]

More than likely, the "corrosion" you have seen had less to do with the generic Prestone coolant and more to do with what type of water it was mixed with.

I didn't specify what coolant was in use (if any) when seeing corroded cooling systems. Corrosion is mostly caused by neglect and not changing the coolant in the first place - or diluting it with water. Green coolant is fine in a 1963 GMC or a 1978 Chevy. It absolutely, positively is NOT fine in a European engine, its not made for their alloys. Whether or not its OK in our engines is up to debate - my feeling is its probably just fine - but its easy/cheap enough to run the recommended coolant, so I do so.

And yes, I use distilled water. I didn't always do so, but I have for many years now. I also always add a bottle of Water Wetter.

 

[IOwnCalculus]

The conventional green (Prestone) coolant also claims protection for 5 years/150,000 miles.

Also worth pointing out that the 5yr/150k green Prestone is not the same as the inorganic green antifreeze that would've been the factory fill; it's still an organic antifreeze similar to the G05. The main difference is the dye, and the lack of any additives that will cause problems when mixed with any other OAT antifreeze. Prestone Prime is the true old-school green and still only advertises a two year lifespan.

I run that 5yr/150k Prestone OAT green in my TJ and my LS-swapped C10, and whenever I get around to changing the antifreeze in them, it'll also be what goes in my Opel GT and my Kubota. My TJ's cooling system was already in piss-poor shape when I bought it so it needed a full flush for many reasons, so changing what was already a murky mix of antifreeze out for Prestone was a no-brainer. Also helps that you can find it basically anywhere and everywhere that sells antifreeze, and that is definitely not the case for G05.

My old WJ is where I developed my distaste for G05, since that had been meticulously dealer maintained and the cooling system never did anything justifying a full flush, but I wanted to, just for the color alone.