Hmmm..... .  Well, I'm not using 50 weight, I'm using 20W50, which is what the driver's manual recommends.  It also does not recommend a 3k mile change interval, but 5k.  I put just over 5800 miles on the oil on my last rip, no bells, buzzers, or lights.  Finally started to look dirty toward the end of the trip, and used about a half quart of oil.

mcneely

---- george jannini <georgejoann@GMAIL.COM> wrote:
>  Why use a synth?
>
>   Because I want to drive all over hell and gone and not have to stop and
> change oil every 3,000 miles.  On a trip to Colorado one time, we ended up
> with 8,000 miles on the clock.
>
>   Try to stretch that 50 weight Castrol GTX for 4,000 miles and you'll get
> a light in your eyes and hear buzzers in your ears.  BTDT.
>
>   I've put as many as 10,000 miles on a Mobil1 15W50 fill and saw nothing,
> heard nothing, except for the time when the oil pump went south...
>
> Geo/ATL

--
David McNeely