Got a nice Prius from the original owner that has only had dealer oil changes and a few at Valvoline and from what I can tell has been using 5w30 conv dino oil in it. No leaks on it that I can see and I want to switch to synthetic oil for numerous reasons. 1. Should I do a motor flush before making the switch? 2. Should I use normal synthetic oil or high mileage syn oil? Been doing some research on SuperTech syn oils and they seem good at a great price of $15 for a big jug.
Unless you have problems with sludge (and even then) Why would you flush a properly operating motor before an oil change? I would just do a couple short duration oil changes monitor then truck on as normal. All oils synthetic or dyno are mixable and compatible no need to flush
1. I wouldn't do a flush. Just the change. But that's only my opinion. 2. If you change year by year, there's no need for longlife oil. I'm using such an oil but only because the price was nice. I also wouldn't choose a special oil for higher mileage. I rather would check, if the specifications fit the local climate: How are the summers in Texas? Maybe a xW-40 would be better than a xW-30. How are the winters in Texas? Maybe a 10W-x would be enough compared to a 5W-x. (The lower the first number, the better the oil keeps thin at colder temperatures. And the higher the second number, the lesser the oil is getting too thin at higher temperatures.) SM-G950F ?
No reason for flush. Don't use an oil labelled "high mileage" unless you have runaway oil consumption, due to valve stem seals or or other flexible seal leakage. If you go to "high mileage" oil, and then go back to regular oil (non high mileage), then you'll likely have valve stem seals leaking copiously. All those high mileage oils do is swell rubber, and that's a one-way street: once you start with it, you better stay with it. Long story short: you can switch to synth oil, no problems.
I used BG Products EPR in our 2010 once I detected oil consumption around 125 k miles. It kept the oil consumption in check as well as clubbing up to 0w-40. All oil flushed aren't created the same.
Good job switching the ol-gal to sythetic TheGraytT1 I do the same thing. I always make sure its Full Synthetic, not synthetic blend, not high mileage version. Just change the oil twice within the first couple weeks of purchasing any used car and there is no need nor benefit to flushing unless you have some other reason to do so.
