FWIW, I've been running DexCool compatible (house brand from Cdn Tire and Walmart, and
Prestone LongLife) for at least 6 years in my Westy, first with the stock 2.1L WBX, and for
the past two years with the 1.6TD engine. No problems with mixing, afaik, and it says so on
the bottles I've used, although I always flush the system fully every two years. I would monitor
things for a while, and consider changing to the dexcool type at the next flush. I figured a 5
year coolant changed every 2 years is probably better than a 2 year coolant at the same
interval. I also never had any sign of a leak in 9 years with the original wbx engine, which still
ran great at 220k kms when I pulled it. Just my $.02, YMMV...

On 23 Oct 2007 at 17:06, Michael Elliott <camping.elliott@GMAIL.COM> wrote:

> So yesterday I was trying to get my coolant system in operating condition
> in preparation for a possible mandatory evacuation order (San Diego county
> fires). I borrowed a working expansion tank pressure cap to replace my
> failed one and was bleeding and re-topping up the system. Time to add some
> more coolant and I saw that the stuff was orange. No more than 250ml went
> in before I paused and thought, "Wait. This seems odd." I did a quick
> Internet search and discovered that Dex-cool (Organic Acid Technology)
> type coolants are not compatible with the ethyl glycol-based coolant I
> have in my van.
>
> At this time I have bigger concerns than a cup of orange coolant in the
> system. But for tomorrow: have I opened the door for some future problem?
>
> --
> Mike "Rocket J Squirrel" Elliott
> 71 Type 2: the Wonderbus
> 84 Westfalia: Mellow Yellow ("The Electrical Banana")
> 74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
> KG6RCR

Shawn Wright
http://members.shaw.ca/vwdiesels
'88 Westy 1.6TD 5 speed
'85 Jetta Diesel 1.6NA