I have a 2000 Toyota Echo. I recently changed oil and started using 5w30 Valvoline MaxLife. Today, I picked up some Mobil1 0w30 Advanced Fuel Economy oil today on a killer deal, $10 for a 5qt jug.
My question is twofold:
1. I hear all sorts of rumors about whether you can/should start using synthetic on a high mileage motor (I'll probably turn over 249k miles in a week or two). Some even say once you start using synthetic, you "can't" stop. Who has some good data to back up any of these claims?
2. I have a consistent oil leak. It drops about 1/2qt every 2-3 weeks. Will synthetic make this any worse?
My 98 GMC K1500 had just over 100,000 miles on it when I switched it to synthetic. I have nearly 200,000 miles on it now. Truck still runs great, and only uses 1 Qt of oil every 5,000 miles. Pretty much when it hits a quart low I'm due to have it changed anyway, so I don't generally add anything to it. When I first switched it to synthetic I was using Mobil1 5W30, I'm currently using Mobil1 0W30, and changing the oil every 5,000 miles.
I agree that #1 is old school thinking. Now, almost all oil is at least semi-synthetic. I would not be surprised if there are oils that are technically synthetics being marketed as conventional.
5,000 is easy to keep track of... If my odometer reading is divisible by 5,000 I know its due. I probably could do a longer interval, but as it is right now, its a 17 year old vehicle with nearly 200,000 miles on it. Every 5,000 has worked well for me so far, so I'm hesitant to change it.
One of the guys I work with is a mechanic for his day job. He advised against it. Most of my gearhead-y buddies I hang out with just dump heavier oil in when they are in doubt. I'm not overly worried - it's a throwaway car, I got offered $300 for it at the local Toyota dealer's "Tuesday Buyback Event"