Loren Williams wrote:
> Regardless of what the manual says, I've seen the inside of a Saturn
> engine with 40k that had the oil changed "religiously" every 6k.
> Hmmmm... wonder why I was looking inside that engine?
Interesting. I've seen the insides of two VW engines that had been
operated for more than 130k (one was at 163k). In both cases, I had
changed the oil and filter every 7500 miles as specified by VW (Mobil
1), and in both cases I was only incidentally inside the engines (oil
pan gasket in one, head gasket in the other). In neither case was there
any visible wear. In the head gasket case, I could still see the factory
hone marks on the cylinder walls, and there was no ridge at the top of
the cylinders, even though the engine had 163k miles at the time. The
same engine now has 192k, runs and sounds great, uses less oil than it
did when new, and I continue to drive the car every day. My experiences
with other cars, including a Ford Aerostar I currently own (150k on the
original engine), Volvos, and BMWs has been the same. I've never changed
oil at 3k intervals in any car, and I've never had an oil-related
wearout or failures of any engine component.
> (I just happened
> to be there when they were tearing it down) The inside of the engine
> looked hideous and required a complete rebuild.
Not because 6k oil drain intervals are in any way unreasonable for
normal passenger car use on paved roads.
Given the use of currently available high quality oils, reasonable drain
intervals per the car's manufacturer, unleaded gas, and paved-road
driving conditions, oil-related wearout or failure is almost a zero
probability in a well-designed modern engine. The dealer-recommended 3
month drain intervals made sense in 1969, but they only add to the
highest-margin dollars a dealership's service department generates in
1999. If you don't subject your car to extreme duty, then the
manufacturer's normal-use recommended drain interval is more than
adequate.
Jay
|