Bill Burton wrote to Roy Witt:   
      
    BB> I am an ASE certified master automobile and auto body technician and   
    BB> have been certified for more than 20 years.   
      
   Impressive.   
      
    BB> I have rebuilt numerous engines and the older ones do need frequent   
    BB> oil changes to prevent harmful deposits and build up,   
      
   My dad was a certified master mechanic and his opinion differed from   
   yours. In the case of the Ford flatheads and Y-blocks and 352/390/405/427   
   engines, that was true because the crankcase and lifter galley always ran   
   too hot, hot enough to allow for sludge to form early. In the Chevrolet   
   and other GM engines, that wasn't the case and so those engines would   
   benefit from a synthetic oil. Before he went nuts and bought a Dodge   
   Caravan, he drove Oldsmobiles and they always lasted well into the 150k +   
   miles without a teardown. My sister inherited his 1953 Olds 98 with over   
   180k on a still factory sealed engine and trans. The only thing he ever   
   had to do to that car was put on front brake shoes and of course, 4 sets   
   of tires. Those tires were always re-caps, as their was a re-capper just   
   up the road from his shop.   
      
    BB> however engines with computer controlls since the late 90's can go   
    BB> 20,000 miles on an oil change with filter changes every 5,000 miles.   
      
   If you read the article, it states that even synthetic oil will last for   
   about 15k before it needs to be changed. I'd trust that statement, rather   
   than take a chance with the oil not being capable of protecting my cars to   
   go 20k...   
      
    BB> I have been using full synethetic oil for over 30 years and have used   
    BB> the above proceedure with no adverse effects. I tested a couple   
    BB> engines using 30,000 mile changes with no problems. Aircraft jets and   
    BB> turboprops have been using synthetic oils since the late 1950's and   
    BB> never change the oil only the filter and keep it topped off.   
      
                   R\%/itt   
      
      
   ... Mark Owen: "Hey, did you ever hear anything about that beer?   
   ... Fellow SEAL: "You believed that s**t, I bet you voted for change too,   
   ... SUCKER."   
      
      
   --- GoldED+/W32   
    * Origin: Texas Lone-Star - Texan, American, USAian  (1:387/22)