Toyota / Lexus A25A-FXS Hybrid engine oil questions

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Newbie here, great forum! I’ve reading a lot about oils and the A25A-FXS engine used on my 23’ Lexus ES 300H. I plan to keep the car for long 12+yr / 100-200k miles; and will adhere to the severe driving conditions OCI of every 5k.

But I still have a few questions for the members of this forum about my specific engine/oil.
  1. Is still 0w-16 recommended for this specific engine even if don’t live in colder climate? Winter is rarely below 50-70F and all year mostly between 70-100F. The USA owner manual recommends 0w-16 or 0w-20 for short interval when 0w-16 is not available. But other warmer regions owner's manual recommend 0w-20.
  2. Given that I have smelled fuel (faint) on the dipstick; but Blackstone UOA came back as < 0.5% Should I be worried and use 0w-20 to counter dilution? I still plan send a sample to OA on my next change to compare. But I have found that when BSL reports < 0.5% rarely goes above 1-2% when using the GC method.
  3. If I drive less than 5k a year, Do I still should change oil at 6 month? Based on a recent BlackStoneLabs study “Motor Oil Age Doesn’t Matter as Much as Mileage: Study”, my guess is that if I only do 5k miles in 2 years, technically the oil should be in similar wear-in condition as 5k in 6 months.
  4. Since it’s a hybrid, the engine is off when EV mode is active. Shouldn’t 5k of ODO use represent probable 3-4k of actual engine running/oil usage (less wear)? Maybe Toyota should also include an engine hour usage monitor.
  5. Do getting a better oil brand or performance filter will have a meaningful impact in wear in/metals? I think going there is just a case of "diminishing returns" and probably overkill since our engines are not high performance.
Thanks in advance. (y)

Below is more info about my driving style and current UOA:
  • Driving Style: Slow acceleration and maximizing mpg; with the occasional hard acceleration for passing and every 1-2 month Italian tune-up (hard acceleration) for cleaning the valves. Currently a low millage driver; probably 5-8k a year. I use Normal or Sport mode for city driving and Eco mode in highway. I'm getting 44-48mpg for a full tack (After Refuel monitoring).
  • Trips: Mostly garaged with short trips (8-20miles) 2-3 times a week and the occasional 1.5-2 month long trip of (150-200mi). Although I try to use EV mode when changing car on our driveway the mode is rarely available and the car is on for 1-3 minutes at most. Maybe that's the principal cause of possible oil dilution on my engine.
  • Gas: I use top tier gas (Costco 90%+ of the time; or Shell).
  • Oil: Lexus dealer included free oil changes for 4 yr at the recommended 10k/12mo interval. I pay for oil changes at 5k/6mo. I suppose they use OEM Toyota oil / filter since they are an authorized exclusive dealer.
  • OA: Did my first break-in oil change at 1,300mi (4 months) and a second at 2,694mi (6 month service). I did a UOA for both and could see 50%+ drop in wear-in metals during the same ~1,300mi interval. My next oil change will be at the 12mo service in August and expecting to have no more than 7.5k ODO miles (<5k oil use). Will send samples to BSL & OA to compare, specially the fuel dilution %. Attached my last BSL report.
scubapr_bs_lab_02.jpg
 
If it were my vehicle, I would use Mobil 1 ESP 0W-30. If this is difficult to find at your local Walmart or if you prefer not to order it from Walmart.com, I would recommend using Mobil 1 Hybrid 0W-20 or Mobil 1 EP 0W-20. Opting for 0W-16 is entirely your choice. This is simply my personal opinion. Choosing an oil with a higher HTHS rating is always beneficial for long-term wear prevention and reliability.

As a side note, the 700 ppm of Dimer Moly present in these oils are designed to enhance the tribo-film in boundary lubrication situations.
 
0w-20 could be a great option. But your best bet is a full synthetic with an OEM approval or meets requirements. I see no real need to run a 30 grade in your hybrid and would possibly remove hybrid fuel economy benefits you bought into with this vehicle. Change it annually based on your mileage of 5k.
 
When you get into these fuel misers the higher viscosity oils may reduce fuel economy as opposed to what the OEM suggested. That's why the OEM doesn't suggest a anything higher than a 16 grade with 20 only temporarily. It takes more energy to pump higher grades vs lower grades. That energy is at the expense of mpg.

FUEL ECONOMY
It's a hybrid right?
 
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Thanks to both! The car is brand new still under warranty, so included dealer oil changes will be 0W/16 I suppose. But I'm more worried about engine protection than fuel economy. Yes it's a Hybrid. How much MPG could I lose 2-5mpg?
 
I would be quite surprised if you lost 2-5 mpg simply by switching from a 0w-16 or 0w-20 oil to a 5w-30 viscosity oil. No way.

In fact, you’d see a larger mpg reduction by operating that hybrid battery in a winter climate and having under inflated tires than you would by moving up one or two notches on the oil viscosity.

Winter temps obviously aren’t your issue so just use what you can live with through the warranty period.

And don’t be surprised if the dealer is using 0w-20 from a bulk tank.
 
Thanks to both! The car is brand new still under warranty, so included dealer oil changes will be 0W/16 I suppose. But I'm more worried about engine protection than fuel economy. Yes it's a Hybrid. How much MPG could I lose 2-5mpg?
Yeah, I think getting into thick oil may lean towards "diminishing returns" as you mentioned. They've designed it to give the overall value around 0w-16. If fuel gets to say 2%+ I could see bumping it up to 20. It'll be fine. Lol 👍 🙂
 
In fact, you’d see a larger mpg reduction by operating that hybrid battery in a winter climate and having under inflated tires than you would by moving up one or two notches on the oil viscosity.

Winter temps obviously aren’t your issue so just use what you can live with through the warranty period.

And don’t be surprised if the dealer is using 0w-20 from a bulk tank.
Agree, I have my tires around 36-38. Also, dealer service form reported "00279-16QTE - 0W16 6X1 QUART/CA" so I suppose they used OEM 0W16; but who knows... UOA does analyze that right? Thanks!
 
Yeah, I think getting into thick oil may lean towards "diminishing returns" as you mentioned. They've designed it to give the overall value around 0w-16. If fuel gets to say 2%+ I could see bumping it up to 20. It'll be fine. Lol 👍 🙂
Thanks! I'll compare the BSL dilution % vs OA on my next OCI. I'll expect OA to report around 1-2%
 
Agree, I have my tires around 36-38. Also, dealer service form reported "00279-16QTE - 0W16 6X1 QUART/CA" so I suppose they used OEM 0W16; but who knows... UOA does analyze that right? Thanks!

It’s quite possible they used bottled 0w-16.

My experience with two different dealerships is the use of either 0w-20 or 5w-30 pumped from a bulk tank. But not in my ride.

The dealer service form said “……….0W16 6x1 QUART/CA….”

Hopefully they didn’t pour six quarts into your crankcase when it calls for 4.8 quarts with filter.?
 
The dealer service form said “……….0W16 6x1 QUART/CA….”

Hopefully they didn’t pour six quarts into your crankcase when it calls for 4.8 quarts with filter.?
Thanks for the pointer! Just double checked now and service sheet says Qty=5 @ $11.32. Maybe that's the internal CASE/PACK description. Relieved! 😮‍💨
 
these engines mated to the Toyota full hybrid system live an easy life. Any event that puts some stress on the engine, starting from a stop climbing a hill making a pass..the motor generators are taking a load off the engine. I would keep doing what you are doing.
 
That engine will outlast the car if you put 0w16 in it it's entire lifespan. I like how you sniffed the oil...that's about as accurate as Blackstone's VERY INACCURATE fuel % guess. Hybrid engines don't run all the time, so they don't get as hot, so the oil is actually thicker than it would be if it were in an engine with oil temps in the 220 F and hotter range. The cooler the engine, the thicker the oil, so the centistokes at which a hybrid engine runs will be lower than the centistokes at which a non-hybrid engine runs. I think you're over-thinking this. Run the OEM-recommended 0w16, and change it every 5000 miles, or run a 0w20 and change it every 5000 miles. Either will be fine, and the MPG change you get between the two will be lost in the "noise" of other efficiency factors. As long as you are using a good-quality oil, there is certainly no rational reason to go up to a 30 weight.
 
As a fellow Toyota Hybrid owner I would use the 0w16 and a good filter. We have 7,300 miles on ours and will bring it in for the first oil and filter change at 10,000 miles. Those Toyota hybrids last forever and I would go by the factory recommendations or change it a little sooner if desired. After the free oil changes I will do it myself and probably a little sooner than recommended.
 
I have ran Mobil 1 Hybrid 0W20 in my 2023 Rav4 Hybrid at 903 miles. Then went back to Mobil 1 0W16 at 4905 miles till my recent change. Now at 10,087 miles today --- seems like the engine is running sweet. Hopefully its the engine good and broken in now.
 
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It’s quite possible they used bottled 0w-16.

My experience with two different dealerships is the use of either 0w-20 or 5w-30 pumped from a bulk tank. But not in my ride.

The dealer service form said “……….0W16 6x1 QUART/CA….”

Hopefully they didn’t pour six quarts into your crankcase when it calls for 4.8 quarts with filter.?
That’s a standard part number that is saved by the service writers desk. They just type that into ADP as a standard. That doesn’t mean it was used. They can type whatever they want.
 
If this data is correct, the oil takes a very long time to heat up. If oil temps remain this low during city driving, I don't see any reason to not use the recommended oil grade:
 
Our first free dealer/Toyota oil change, they put bulk 0W-20. I've done it myself ever since because the dealer says 10,000 mile changes one a year, not 6 months. I change oil every 6 months regardless of the mileage. BTW, we have the same engine on our 2022 Toyota Rav4 Hybrid and use M1 0W-16 or 0W-20 if not available.
 
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