2008 Prius 170k Miles - Synthetic Oil vs Conventional Oil

Stick with conventional.

 

The only downside to switching to synthetic at this stage is that the synthetic can break apart sludge/oil build up and start leaking from there.

 

Is this still the consensus on sticking with conventional? I’ve never used synthetic, the dealer recommends conventional, 5k changes, its half the price of synthetic and my Gen 2 is approaching 200k with no problems whatsoever. Not sure why anyone changes.

 

At 200k miles I would not change. It probably eats a lot of oil. Tends to clog the throttle body pretty good though.

 

I think anymore it's personal preference. I changed to Synthetic at 160k because I tend to have my car sit for periods of time, and also tend to skip some oil changes. There are some months where I could potentially be changing the oil weekly if I went with every 5k miles, though then the car would sit for a month or two and not get driven at all, so it goes through extremes.

I have no issues with leaking, it does use a little oil if I'm heavy on the pedal, but nothing unusual. I feel like it runs a little smoother on the synthetic, but nothing that would force me to change from conventional if I was home all the time and could just change my oil whenever.

My reasoning is that there are people who run synthetic oil, and just change the filter from time to time and get the oil tested/ top off missing oil. They have went 100's of thousands of miles between oil changes, and had no issues with the oil breaking down, or parts going bad. I figure if I'm kind of hard on it by not changing the oil right at 5k miles, I have a little wiggle room, but I'm certainly not saving any money because of the higher cost of synthetic and buying the filter designed for longer intervals.

On my larger cars, trucks and van I use Rotella oil for semi trucks with no ill effects, but I don't think the delicate little Prius motor would like that stuff too much.

 

Nope, doesn’t consume any oil between 5k changes. Get mpg in the 50’s routinely.