Toyota / Lexus A25A-FXS Hybrid engine oil questions

Is not 5W-30 too thick for this engine? CCN advises against such because the electronic variable oil pump is calibrated to 0W-16. (View minute 6:26)

5W30 is NOT too thick for this engine. However this engine is designed to run efficiently and adequately protected on 0W16 and now clearly 0W8 under favorable circumstances.

In service since 2016, the Dynamic Force series engines also have an emissions compliant cooling system, that warms up quickly and at the same time provides optimum cooling in almost all load ranges.

Do you tow a boat ?
Do your driving conditions lead to concerns about excessive fuel dilution ?

If yes, then 5W30 might be a good idea.

If no, then 0W16 is fine.
 
Speaking of trust are you going to trust a mechanic who's been in the business for 20 years (certified), rebuilds engines sees hundreds of cars a year or some "bobistheoil" guy that says 10000-mile oil changes are fine that the oil pump is or is not this but won't help you pay when the engines dies? Play it safe! Do timely maintenance.
 
Thanks to ALL! I found all this discussion and topic very interesting. Fortunately I'm in a warmer climate so I don't get the extreme cold temperatures most of lower 48 is experiencing right now.

I was looking into the overseas manual and although it shows multiple grades as acceptable, it still shows 0W-16 as preferred.

Anyhow, without deviating much into the oil pump discussion, my issue is more with the apparent "Fuel Dilution" on the Hybrid engine as the oil apparently does not get hot enough on short drives < 10-20 miles; and also the frequents "Starts/Stops" of the Hybrid ICE.

I'm still adhering to the "Special Operating Conditions" of 6mo/5k OCI. But since right now I'm low millage driver, at 6 months I'm about 2-4k of used oil @ OCI; so no much concern there at the moment. Just learning!
 
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Speaking of trust are you going to trust a mechanic who's been in the business for 20 years (certified), rebuilds engines sees hundreds of cars a year or some "bobistheoil" guy that says 10000-mile oil changes are fine that the oil pump is or is not this but won't help you pay when the engines dies? Play it safe! Do timely maintenance.
Does he tear apart perfectly functioning engines that get 10,000 mile oil changes or does he only tear apart broken engines that get 10,000 mile oil changes?

I don't think the man is wrong or uninformed. But I do think it's worth considering the engines a mechanic is likely to dig into vs those they don't.


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Speaking of trust are you going to trust a mechanic who's been in the business for 20 years (certified), rebuilds engines sees hundreds of cars a year or some "bobistheoil" guy that says 10000-mile oil changes are fine that the oil pump is or is not this but won't help you pay when the engines dies? Play it safe! Do timely maintenance.
Probably neither. I have known, seen, and heard of many mechanics who were good at what they do but also didn’t know exactly how things fundamentally worked. I know a specific mechanic who swore by 15W40 Rotella and told clients to run it at 3K miles in applications where it was not necessary. I’ve also seen engineers who were great at design but who couldn’t physically torque a bolt properly to save their life.

Assembling an engine and designing an engine are not the same skillsets. In my experience engineers don’t make good mechanics and mechanics don’t make good engineers. Each should stay in their respect lane.
 
Oil is too cheap compared to engines to push it too far. Low tension piston rings changed the game. I'll go with the guy with experience in this day in and day out.
 
I'm considering using either Mobil1 or Valvoline 0W-20 Hybrid oils for those in between 5k OCI and DIY. Apparently those are formulated to minimize fuel dilution and moisture. Could they be just marketing gimmicks?

Basically:
  • Every 10k: 0W-16 *free / dealer included up to 40k
  • Every 5k: 0W-20 *Hybrid oil DYI
 
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I'm considering using either Mobil1 or Valvoline 0W-20 Hybrid oils for those in between 5k OCI and DIY. Apparently those are formulated to minimize fuel dilution and moisture. Could they just be marketing gimmicks?

Basically:
  • Every 10k: 0W-16 *free / dealer included up to 40k
  • Every 5k: 0W-20 *Hybrid oil DYI
With normal driving conditions and 5K OCI’s any of those will be just fine.
 
Today out of curiosity I decided to monitor the oil temp on a 25mi city drive. What I found really strange was that the oil temp was higher on EV mode vs ICE. When on ICE the temp was 140F and 160F when on EV. This was using the Carista APP. Does that make any sense?

Edit:
For reference outside temp was 88F, coolant temp was 165F, and intake temp was 97F
 
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Today out of curiosity I decided to monitor the oil temp on a 25mi city drive. What I found really strange was that the oil temp was higher on EV mode vs ICE. When on ICE the temp was 140F and 160F when on EV. This was using the Carista APP. Does that make any sense?

Edit:
For reference outside temp was 88F, coolant temp was 165F, and intake temp was 97F
wonder if there is some type of heater, to keep oil nice and hot, so engine does not restart with cold (thick :) ) oil while on the move
 
Initially, when you let off the throttle and the engine idles/switches to EV mode (like at a stoplight or coasting), the oil temperature goes up almost immediately by 10 or 15 degrees F. When you put your foot on the accelerator and ICE turns back on, the oil temperature drops immediately until it starts creeping up due to the production of engine heat after sustained combustion/heat generation. Yeah… I don’t know what’s going on but it’s reproducible. The change in oil temperature is associated with a change in oil pressure (which drops to zero at idle followed by the oil temperature creeping up). I was wondering whether the oil temperature probe has a quirk with it that reads differently in the presence of oil flow/pressure. I like the oil heater idea but it doesn’t explain the immediate drop in oil temperature once I hit the gas.
 
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Initially, when you let off the throttle and the engine idles/switches to EV mode (like at a stoplight or coasting), the oil temperature goes up almost immediately by 10 or 15 degrees F. When you put your foot on the accelerator and ICE turns back on, the oil temperature drops immediately until it starts creeping up due to the production of engine heat after sustained combustion/heat generation. Yeah… I don’t know what’s going on but it’s reproducible. The change in oil temperature is associated with a change in oil pressure (which drops to zero at idle followed by the oil temperature creeping up). I was wondering whether the oil temperature probe has a quirk with it that reads differently in the presence of oil flow/pressure. I like the oil heater idea but it doesn’t explain the immediate drop in oil temperature once I hit the gas.
Yes, Exactly like that!
 
wonder if there is some type of heater, to keep oil nice and hot, so engine does not restart with cold (thick :) ) oil while on the move
That make sense. ^
It took me by surprise. I was expecting the opposite, higher when throttling, lower when idling/Ev.
 
That make sense. ^
It took me by surprise. I was expecting the opposite, higher when throttling, lower when idling/Ev.
There are various stages of the complex cooling system allowing flow or no flow via shut off valves governed by the ECM.

A fundamentally new cooling system for Toyota - with an electric pump, electric thermostat and shut-off valves.

cool_system_2.png
1 - radiator, 2 - reserve tank, 3 - water inlet with thermostat, 4 - water pump, 5 - cylinder block, 6 - cylinder head, 7 - EGR cooler, 8 - EGR valve, 9 - throttle body, 10 - flow shutting valve (heater), 11 - heater radiator, 12 - transmission oil cooler, 13 - flow shutting valve (ATF), 14 - oil cooler. a - upper water jacket, b - lower water jacket, c - sub-jacket, d - passage

The electric pump allows you to adjust the coolant flow at the discretion of ECM.

cool_pump.png
1 - water pump. b - stator, c - rotor, d - shaft

The accelerated warm-up function provides the fastest reaching of economical operation modes and is performed by two shut-off valves that can exclude the heater and the transmission oil cooler from the circulation.

cool_system_operation.png
1 - engine, 2 - flow shutting valve (heater) (closed), 3 - flow shutting valve (ATF) (closed), 4 - heater radiator, 5 - transmission oil cooler, 6 - water pump, 7 - water inlet with thermostat, 8 - radiator, 9 - flow shutting valve (heater) (open), 10 - flow shutting valve (ATF) (open). a - early warm-up, b - heater priority, c - output enhancement, d - max cool, e - when current is not applied to the thermostat with heater, coolant flow volume is increased, thus output is enhanced. additionally, applying current to the thermostat with heater decreases thermostat opening temperature, ensuring cooler efficiency, f - this discontinues coolant flow of the heater radiator unit sub-assembly, ensuring cooler efficiency, g - EGR cooler.

When the current is applied, the valve is held in the closed position. If the current is not applied and the pump is running, the valve opens under the force of the coolant flow and remains open until the flow stops.
 
There are various stages of the complex cooling system allowing flow or no flow via shut off valves governed by the ECM.

A fundamentally new cooling system for Toyota - with an electric pump, electric thermostat and shut-off valves.

cool_system_2.png

1 - radiator, 2 - reserve tank, 3 - water inlet with thermostat, 4 - water pump, 5 - cylinder block, 6 - cylinder head, 7 - EGR cooler, 8 - EGR valve, 9 - throttle body, 10 - flow shutting valve (heater), 11 - heater radiator, 12 - transmission oil cooler, 13 - flow shutting valve (ATF), 14 - oil cooler. a - upper water jacket, b - lower water jacket, c - sub-jacket, d - passage


The electric pump allows you to adjust the coolant flow at the discretion of ECM.

cool_pump.png

1 - water pump. b - stator, c - rotor, d - shaft


The accelerated warm-up function provides the fastest reaching of economical operation modes and is performed by two shut-off valves that can exclude the heater and the transmission oil cooler from the circulation.

cool_system_operation.png

1 - engine, 2 - flow shutting valve (heater) (closed), 3 - flow shutting valve (ATF) (closed), 4 - heater radiator, 5 - transmission oil cooler, 6 - water pump, 7 - water inlet with thermostat, 8 - radiator, 9 - flow shutting valve (heater) (open), 10 - flow shutting valve (ATF) (open). a - early warm-up, b - heater priority, c - output enhancement, d - max cool, e - when current is not applied to the thermostat with heater, coolant flow volume is increased, thus output is enhanced. additionally, applying current to the thermostat with heater decreases thermostat opening temperature, ensuring cooler efficiency, f - this discontinues coolant flow of the heater radiator unit sub-assembly, ensuring cooler efficiency, g - EGR cooler.


When the current is applied, the valve is held in the closed position. If the current is not applied and the pump is running, the valve opens under the force of the coolant flow and remains open until the flow stops.
Thank you very much for the detailed explanation! So basically when the ICE is off (EV Mode) the system is open keeping the stationary oil hot (160F). Then when the ICE is working the system closes so the flowing oil does not get hotter; and since it's flowing mixing with colder oil thus the lower 140F. Correct?
 
Thank you very much for the detailed explanation! So basically when the ICE is off (EV Mode) the system is open keeping the stationary oil hot (160F). Then when the ICE is working the system closes so the flowing oil does not get hotter; and since it's flowing mixing with colder oil thus the lower 140F. Correct?
I think there is more to it than that. But the system definitely is prioritizing the engine operating temp running cooler than other designs.
 
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