Subject: STOP THE SURVEY: Prestone Orange...

c1j1miller at c1j1miller at
Wed Jun 14 16:44:46 EDT 2006

These new coolant formulations are designed for a high aluminum content 
motor.  Newer Audis (pink coolant factory fill) appear to be fine with 
it if you flush out all the old stuff.

Seems like the potential issues relate to gasket failures, rust and 
sludge for iron blocks like your 200 has, poor protection of lead and 
copper soldered systems (replacement radiators and heater cores?  
What's the OEM construction?  Isn't the typical failure at the 
gasket??), poor protection from cavitation erosion (seem to recall some 
waterpump impellers having this issue), and softening of some 

In general the long life coolants seem more sensitive to low coolant 
concentrations (40% and less), which generally result from poor mixture 
control and from topping up a system with only water.

The recommendation is that if you change to a long life coolant, make 
sure you get at least 90% of the old coolant out, which they say is 
only possible by using a coolant exchange machine (or many full system 
fills/flushes with water, running the engine to hot enough to open the 
thermostat each time, then draining and filling...).

Chris Miller, Bolton, MA  c1j1miller at
'97 Audi A4tq, '91 coupe q, '85 4ksq, '81 VW Scirocco
'91 200q20v site ==>

Date: Wed, 14 Jun 2006 16:04:10 EDT
From: TooManyAudis at
Subject: STOP THE SURVEY:  Prestone Orange...
To: 200q20v at, quattro at


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