<VV> LM Correct Oil Viscosity

[HallGrenn at aol.com]

With all the discussion about engine oil I went back to my owner's manuals  
for '66 and '68 and the service manuals for the same years.  In 1965 the  
single weight oil recommended for operation above 32 degrees F was 30.  In  
1968 the single weight oil recommended for operation above 32 degrees F was  
20.  30 weight oil was only recommended for operation at temperatures 90  
degrees F and above in 1968. I have never used 20 weight oil in any of  my 
Corvairs.  I have used 30 weight oil almost exclusively except in  winter when 
I used a good quality 10W-30.  In high summer I have also  usually used a 
single 40 weight oil.  I also changed the oil every 2,000 to  3,000 miles 
regardless of time.
 
And this was not synthetic oil of course.  The single 20 weight oil  was 
being recommended for A.I.R. smog engines that could and often did  run hotter 
than the earlier engines.  Was GM trying to get us into  Vegas early?
 
Bob Hall
Group Corvair
Corvanatics
CORSA