Which Antifreeze to use?

L DC ldc007usa at yahoo.com
Tue Nov 1 20:50:38 PDT 2011

Thank you all for your input!!.
The coolants mentioned, as well as apparently recommended by Audi/VW, at least for older vehicles like those from 80's to early 90's, all contained SILICATE as the main corrosion inhibitor. And silicate can turn into a tough, deposit at which point will clog a radiator as it occurred in my QSW's radiator. This apparently happens after the silicate "drops out" or its properties as an inhibitor are exhausted typically between 18 months to a year.  In the case of my car's radiator, that life span seems to have been shorter.  The radiator in my car looks like the first picture on the link below:
Anyway, the alternative is pretty much other antifreezes contain Organic Acid Technology, OATs, or a "hybrid" of it with low silicate content as corrosion inhibitors. This OATs and or HOATs are argued to last longer than silicates and is safer for aluminum. But are they safe for the brass/copper radiator combination in our older vehicles? Would OATs corrode radiators that are not made of aluminum?
In case one goes with an antifreeze containing silicate, I guess the key here is to watch for evidence of silicate "drop out" in the coolant reservoir tank and flush and R&R antifreeze in combination with distilled water.
Thanks again in advance for your input.
Best Regards,

From: Joshua Van Tol <josh at spiny.com>
To: L DC <ldc007usa at yahoo.com>
Cc: "quattro at audifans.com" <quattro at audifans.com>
Sent: Tuesday, November 1, 2011 8:45 AM
Subject: Re: Which Antifreeze to use?

For the same price as the blue stuff, you can get the new and improved
G12++ coolant.


If that link doesn't work search for cooling system parts for any late
model audi, or look for one of these part numbers:

You'll want to flush thoroughly first. Or just flush well, and use
good quality "normal" anti-freeze and change every 2 years or so.
Either way will probably work fine.

On Tue, Nov 1, 2011 at 12:57 AM, L DC <ldc007usa at yahoo.com> wrote:
> Hi all:
> I will be replacing the radiator in my '87 VW QSW since the one on the car is about 30-40% clogged and developed a leak upon doing an extended period flush with CLR.
> At over $273 for a new radiator from the cheapest place (AutohausAZ.com), I want to make sure to use the right combination of coolant and distilled water to prevent clogging as much as possible.
> So what is your collective advised on the matter?
> A lis in another forum indicated that the Blue Antifreeze previously sold at VW/Audi dealerships has been discontinued. Does anyone know if this Penstosin (although not cheap)  Blue Antifreeze is similar to the discontinued stuff?
> http://tinyurl.com/6acq36x
> I last used Zerex G05 (pink stuff) and previously used Prestone (found to be crappiest and worst of all antifreeze).
> Thanks in advance for your value insight.
> Best Regards,
> -Louis
> _______________________________________________
> quattro mailing list
> http://www.audifans.com/mailman/listinfo/quattro
> http://www.audifans.com/kb/List_information

More information about the quattro mailing list