Audi Junkie

Here's a handy reference chart for coolants, this one includes a compatibility matrix.

As I've said before, coolant compatibility is less of an issue than made out to be. This chart helps define what actually is compatible. Compare G-11 to "Conventional High Silicate" (Heavy Duty) and compare G-12 to Dexcool/OAT (GM) then compare G-05/HOAT/Hybrid (Daimler/MB). You will see that Olde Green Prestone/G-11 is only compatible with the same type antiquated formula, that should be clear now. (pun intended) The noteworthy point is OAT/Dexcool/G-12 is "compatible" with HOAT/G-05/Daimler. This should indicate a high degree of interchangability and compatibility for people who want to changeover to a Hybrid Organic Acid Technology from G-12.


Remember, MB/G-05 has the longest successfull track record of any modern coolant formulation. Also, as far as compatibility goes, Mercedes shares coolant parts suppliers with VW/Audi. MB is so concerned about their coolant containing silicates rather than strait OAT/Dex/G-12, the expansion tank actually contains a sack of silicates to replenish them, even in correctly-formulated applications.

Switching over G-12 to G-05 is desirable and safe with minimal flushing due to their compatibility as indicated here.

Draw your own conclusions but this is reliable info.<ul><li><a href="http://www.eetcorp.com/antifreeze/Coolants_matrix.pdf">http://www.eetcorp.com/antifreeze/Coolants_matrix.pdf</a</li></ul>

pipebender

I switched to G05 from factory G12 with proper flush. The coolant right after the flush was yellow/clear, then slowly changes to G12-like pink couple weeks later. I think it's the residue from G12 in trace amount so I am not that concern since I am only going to run it for 2yr max. BTW how's the M1 ATF in P/S experiment holding up?

Audi Junkie

My lil cousin's Cabrio came back from a cracked resevior at the local garage with Dexron in the Pentosin system. I thought it was a good cantidate for putting in M1 ATF since a grand flush would not be needed and the system parts itself were identical to the year before when Dexron was indicated for it. Longer life, lower friction, better in cold than plain Dexron. It's a small car and probally not hard on the PS system, but my theory isin larger/harder apps, the Pentosin is just too thin, M1 is a good shot thicker, but not overly thick in cold. Pentosin is more like an aircraft hydrolic fluid, used in super-cold and not over-heated from use.

My coolant chart begs the question, if G-12+ is compatible with both G-12 and G-11...it is unique because mixing highly silicated and OAT seems to be the one rule indicated there.