quote:Yeah, but Tim, with synthetic, at least he'll have the advantage of "seasoned" synthetic motor oil with its load of wear metals and silicon grit building up and "microfinishing" his bearing journals, cam lobes, and cylinder walls over that 7,500 mile interval... Of course if his engine uses 1 quart in 3000 miles and he elects to change the filter at 3,000 miles for cleanliness' sake, then he gets to add two quarts at the 3000 mile mark. In 7,500 miles that's 9 quarts every 7,500 miles (18 quarts every 15000 miles = $90.00*), not counting the cost of oil filters. Of course, stupid me is changing my "inferior" 68 cent/qt Target closeout Chevron Supreme 10W-30 dino oil every 3,000 miles along with my $2.00 Kmart closeout WIX-made Castrol "MaxPro" oil filters for, let's see, a grand total of $27.00 over 15,000 miles. And, I'm getting under the car at essentially the same mileage intervals he is if he elects not to chance accelerated wear of bearing, cam lobe, and cylinder wall surfaces over the full 7,500 mile interval with a filter change at 3,000 miles. And, I'm not leaving 2 1/2, or so, quarts of polluted oil in the sump every other oil change... My sarcasm aside, I really don't have a problem with those who elect to go with the high price "spread". The fact is, one can make an argument for either oil maintenance philosophy. My point is that in the case of vehicles in which dino oils are permitted by the manufacturer's warranty, I've never seen hard evidence that using synthetics at 7,500 mile change intervals necessarily results in lower wear rates than using the highest available ILSAC/API performance grade dino in the designated viscosity grade(s) and changing at 3,000 miles either. How the vehicle is driven, and the conditions in which it's driven, will play a more profound role in how fast the engine tanks than the type of oil used. IMHO. Temperature extremes at either end mandate more frequent oil/filter changeouts. Ditto that for heavy stop-'n-go driving or pulling loads. *Probably two or three bucks less since the ever-shrinking oil filter has obviated the 1 quart capacity. [ May 31, 2003, 01:32 PM: Message edited by: Ray H ]
Originally posted by timzak: IMO, it comes down to personal preference, cost is a wash.
quote:Strawman Argument (poor debating tactic): I never said I add oil to my car. Conventional 15,000 miles: $2/qt * 4qts * 5 changes (once per 3000) = $40 [+ $20 per JiffyLube or Dealer visit = $140] Synthetic 15,000 miles: $4/qt * 4qts * 2 changes (once per 7500) = $32 [+ $20 per JiffyLube or Dealer visit = $72] I save myself roughly 50% by using synthetic oil. Of course your numbers will vary depending on size of pan, whether you do the change yourself, et cetera. . BTW, if you're adding one quart of oil every 3000 miles, your car is seriously knackered! Better get it fixed. Or else switch to a thicker oil like 10W-40 that is less prone to leakage. Or better yet, switch to a synthetic that has a higher flame point and fewer VIMs, and therefore virtually no burnoff. [ May 31, 2003, 08:36 PM: Message edited by: troy_heagy ]
Originally posted by timzak: And if you have to add a quart every 3000...?