03 May 12 13:49, Mark Hofmann wrote to Roy Witt:   
      
    RW>> The oil may not be, but the polymer additives they use shrink or   
    RW>> expand at those temps changing the viscosity along the way.   
    RW>>   
    RW>> As you suggest, pure engine oil will thin out at higher temps.   
    RW>>   
    RW>> I can varify that by a story my dad used to tell about his earliest   
    RW>> experiences with cars in the 1920s. In the winter they would build a   
    RW>> fire under the engine's oil pan to thin out the oil before they   
    RW>> 'hand cranked' the engine to start it. Of course, that was before   
    RW>> multi-weight oil was invented.   
      
    MH> Interesting..  I didn't know about the polymer additives that effect   
    MH> the viscosity in different temperatures.   
      
    MH> I scheduled to take my Monte Carlo back to the engine shop because   
    MH> there appears to be a small leak somewhere around the oil pan gasket.   
    MH> I wouldn't normally be concerned, but it is still under warranty for   
    MH> 2 more years.  If that gasket needs to be replaced, that is a pain!   
    MH> You have to drop the sub-frame!   
      
   I've seen that done in the late model Malibus. It's not that bad of a job.   
      
    MH> While I had them on the phone, I ran the lifter tap (on cold start)   
    MH> question by them.  He said not to worry about it unless you hear that   
    MH> noise all the time while driving.  Under a minute of tap on warm up   
    MH> on those engines appears to not be unusual.   
      
   Apparently not.   
      
    MH> He didn't think that changing the oil types would make a difference   
    MH> and said to stay with 5w-30 (I have always used 10w-30).   
      
   Whatever the owner's manual tells you to use...   
      
    MH> I believe it is worth trying 10w-40 or 5w-40 - as I really don't see   
    MH> that causing any problems.   
      
   I could see  using a multigrade oil like 10w-50, but only in South Texas   
   and the desert south west and only during the summer months. In MD, 10w-30   
   should be the normal oil to use in summer.   
      
   It gets to 100 here for a few hours each day, usually late in the   
   afternoon. The same for New Mexico, Arizona and California and they're 5   
   or 6 degrees further north latitude than we are.   
      
      
                   R\%/itt   
      
      
     ... Only those who will risk going too far can possibly   
     ... find out how far one can go ~ TS Eliot   
      
      
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