Chevrolet Repair: Oil Change/Timing Chain, high mileage car, chevrolet astro

Question
Hi Mark,
Own 1989 Chevrolet Astro,4.3 liter-V6,156,000 mi.,runs good, never valve cover leaks. Use Castrol "High Mileage,10W40". Change every 3000-3500 mi. One mechanic said 3000 mi. oil change too often; says companys trying to sell more oil. Gets dark caramel look around 3000 mi. Should I change then, even if 3000 mi. oil change  too soon? Is it better to go by color of oil, and not mileage?
My timing chain is at 116,000 mi. When should I change? Not making any noise-doesn't run rough.

Thanks!

Mike E.

Answer
Hi Mike, Changing your oil too often, Wow thats a new line. Your doing just what it takes to keep a high mileage car going without problems. I had 2 Astros 1985 and 1995 and they both had over 160k on them and never used oil or leaked it. The engines had not been touched, only the spark plugs changed at 100k and that was it. The timing chain should last for at least 150k. The thing that wears them out is high rpms, racing the engine. Keep up what your doing, every 3000 miles whether it needs it of not!!

Have a Nice Day     Mark