Miata Mailing List: May 1999, Message #156

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> Has anyone had long term durability problems using 5W-30 to lessen HLA
>  >noise on start up?
>  >MartyD
>  >94M

  Started using Mobil-1 10W-40 just after break-in at 5,000 miles in 89.  
Switched to 5W-30 around 50,000 miles.  For Rocinante's 200,000 mile change I 
tried 0W-30.  Oil pressure and compression is still as new.  Oil consumption 
is up a bit from 89 levels when I drive hard (and I always do), but that's to 
be expected.  I use change intervals of 5,000 miles with a new Mazda filter 
each time.  When filter cost is factored in, this is about as economical as 
3,000 mile changes of dino sludge.
  Lifter clatter, which was a problem from the start has almost never 
recurred with the synthetic, unless I push change intervals past 6,000 or 
autocross with the oil level more than 1/2 quart low.  Since the problem 
seems to be one of HLA clearance variations, some cars respond to heavier 
oil, and some lighter.  An unlucky few who have some HLAs too tight and 
others too loose can get relief only with carefully selected new lifters.  
Hmm, come to think of it, I wonder if the out-of-tolerance situation is with 
the head bores, the lifters, or both?
  Foureagles