Pentosin

[Jerald S. Beer]

My car has only seen 7.1,  now over 200k miles and still on original rack 
(at least until my car reads this!). Other than the different temp ranges, 
not sure why mixing would be prohibited. As others suggested, the 
conventional wisdom was mixing forward was ok (regular to synth), but not 
backwards (synth to regualr). Audi, in theory,  must have had a reason for 
the higher spec for the UrS6[hmm, maybe like the UFO's?? :-)].
Regards,
Jerry
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