Hi All My son just bought a used 2015 Prius with 71,000 miles. Against my recommendation he bought the car even thought the guy didn’t provide much of an engine oil maintenance record. He claimed he did a lot of the oil changes himself and claimed he did it every 3-4,000 miles. As a precaution I want to clean the engine inside of the engine for any gunk build up. I know there are products such as Engine Medic which is an engine flush. You pour it in just before you do your oil change, let the engine idle for 5 min then change the oil. This supposedly removes most of the sludge. However, I know the Prius engine usually doesn’t idle so a little driving may be required to get the engine running. Anyway, I would like to know if you have any other recommendations for cleaning the inside of your engine to remove gunk build up. Many Thanks
Well, that's pretty low miles so even if they guy only changed it every 5,000-7,500 miles it's probably good. How did the oil look when you changed it out? My son-in-law drives a VW with turbo and likes to do flush with Liquid Molly about every two years. I helped him with the last one and, after running it for about 20 minutes, drained it out and the oil wasn't really hardly even dirty. (Those GDI engines can sludge up pretty good, especially with a turbo on there.) You might want to give that a try if you still want to do a flush.
2015 is such low miles is a big red flag, I would run a carfax just to verify the mileage matches the records. If the mileage is accurate, there shouldn't be a need for engine cleaning. You should just change all the fluids and then go from there. Run the car for 1000 miles and see how dirty the oil is afterwards. If it's burning oil, you will also be able to see how much oil it's burning after 1000 miles and then set a maintenance plan for the car.
Glad your son didn't listen to you and bought the car anyways! Great score if it's only got 71K miles on it. As for the engine flush, any brand will work fine and most of them are for much larger engines so you only need to use half a bottle. I'd reccomend against driving it. Just start the car twice, that should be enough to get the Engine Flush to do its job. Also I've found if you switch from standard motor oil to full synthetic it helps clean the engine out a little bit as well because the oil quickly gets darker on batch of full synthetic than it does in future changes.
I have a 2015 with 105k now...I change the synthetic oil twice a year, usually at 5-7k miles...not using any oil at all. I use cheap oil...have been for 40 years or more, no problems ever. I believe changing it is more important than buying expensive oil.
Well of course it depends what he paid for it also. I mean people are asking $7,900 for these things with miles on them so something like this might be nine grand I wouldn't spend nine grand on a generation 3 Prius not in this world I squabbled about paying $4,500 many years ago and that turned out to be well anyway.
We did a Carfax. The mileage matches. The only records of oil changes reflected on Carfax were done at a dealer up to 2019. There are no records after that. The guy said he took it to a local mechanic or did it himself so that may explain the lack of records after that. Either way there are no records after 2019. He said the oil looked good. It was a fairly light brown and the guy said the last change was done 4 months ago. For a piece of mind I was going to do a flush and then change the oil again after 500 miles. Maybe I’ll take JC91006 advice and do it at 1,000 instead. I plan on putting synthetic oil in. Then just have my son change it every 5,000. Much easier to remember.
Only synthectic oil should have been used. It's pretty hard to find non synthetic oil any longer If you changed the oil, and filter, and you use synthetic oil, no "flush" should be needed.
Try adding a bottle DMSO Liquid Concentrate 99% Pure 16 fl. oz. to the oil before replacing it. It washes away varnish stains inside the engine well. It can also be poured in with new oil to flush the engine, but then it needs to be removed. The color of the new oil will change to the black color of oil in a few minutes of engine operation, which will show its excellent cleaning properties. The product works at high temperatures! The engine needs to be warmed up well, then add the product.
Just keep a little bit for yourself "DMSO is an effective systemic stimulating healing product that offers relief of muscular and bodily pains and aches among a multitude of other things."
Our 2010 just went by 101k kms (~63K miles). And our Toyota service records don't have a single oil change. Danger danger... I'd just do an oil change. And then turn your attention to EGR cleaning, sooner than later. See top two links in my signature (on a phone turn it landscape to see signatures)
You'll spend nine grand on a rebuilt title in VA, but in NC there is probably no difference in price between clean title or rebuilt one.
Carall, why do you think so? I'm driving a 2015 salvage that I paid nine grand for back in 2017.It had 27k mi now has 105k...nothing has needed repairing on it.
I would skip the flush and just change the oil. The critical variable valve timing components won’t be cleaned by a flush if the engine was neglected but flushes can accelerate wear. No matter what you do some of the flush’s solvents will remain in the engine. Synthetic was always required for gen3 Prius engines. Do change oil every 5k miles instead of Toyota’s recommended 10k miles. The real problem is carbon buildup caused by a flowing egr system picking up exhaust before the cats. Carbon in the egr, intake manifold and the heads. Oil flushes won’t even touch these buildups since there is no oil in those areas. However if the car is really a low mile example (rollbacks are easy and advertised here) then low miles means low carbon. On a 2015, $2400 brake by wire master cylinders and the $2500 hybrid battery are bigger concerns. Neither of them see oil or aftermarket oil products. Having the brake system flushed by a dealer with Techstream is a flush I would recommend. Having the hybrid battery cooling fan cleaned is a service that might prolong the hybrid battery life. Knowing where that fan’s intake is to avoid blocking it with stuff in the back seat is useful as well.
