recommended viscosity

[PeterBergin at aol.com]

I live in Minnesota and use Mobile 1 20/50 almost year round.  The car  
will start at -20F.  It does not sound happy turning over at that  temp.  (I 
park outside) If we have prolonged cold I will use a Mobile 1  10/30.  I 
sometimes go up to the UP snowmobiling and have started the car  at -35 with 
10/30 (fingers were crossed!).
 
I have one of those Fumoto quick change valves, so I can just reach  
underneith and flip it.  Have used that for 10 years, no issues.
 
Pete, 91 Avant 238k