The Atkinson quandary

[Speedy3861]

OK, I now own 2 Honda hybrids with the 2.0 Atkinson engine and some questions have popped up during my thoughts about servicing them.
The Honda Hybrid system essentially uses the ICE as a stationary generator while the car functions primarily as an electric vehicle. The questions I have are:
With the engine operating intermittently to charge the battery, does it ever reach operating temperature? Does the oil reach temperature sufficient to evaporate fuel from the DI system? I know the engineers at Honda are pretty competent and they have undoubtedly considered these issues.
I have never blindly followed the MM system, im probably too proactive but what are thoughts and experiences in proper management of this system. Currently planning on AMSOIL Signature Series 0w20 using its high PAO and group IV base to offset the high start/cycles and possibly high oil dilution from the DI system. Am I unduly concerned or are these issues not really a problem? Really enjoying the car and the low fuel consumption, drivability is excellent. Looking for some real-world experience with this system. What OCI's should I consider? Liked the Civic so much wife just bought a 2023 Accord Hybrid Sport L Certified Pre-owned with 25,000 miles with essentially the exact same power train.

 

[SC Maintenance]

Yours are operational questions and will change by owner. Buy a cheap OBD dongle / software and log the temps.

I presume the engine / generator run almost constantly at interstate speeds?

I am not sure the synthetic "Atkinson" cycle doesn't really play into your temperature questions either, but I could be wrong on that also as they tend to be more thermally efficient.

 

[ATex7239]

Hybrids are known to potentially dilute. 5,000 miles or 6 months would be my default answer without more info on conditions and usage.

 

[FZ1]

Hybrids are known to potentially dilute. 5,000 miles or 6 months would be my default answer without more info on conditions and usage.

This^^^^^^^^^. I'd want a "slick" oil for all those starts/stops. You could look at an oil analysis for your cars on Bob. Good luck with them. .02

 

[kschachn]

OK, I now own 2 Honda hybrids with the 2.0 Atkinson engine and some questions have popped up during my thoughts about servicing them.
The Honda Hybrid system essentially uses the ICE as a stationary generator while the car functions primarily as an electric vehicle. The questions I have are:
With the engine operating intermittently to charge the battery, does it ever reach operating temperature? Does the oil reach temperature sufficient to evaporate fuel from the DI system? I know the engineers at Honda are pretty competent and they have undoubtedly considered these issues.
I have never blindly followed the MM system, im probably too proactive but what are thoughts and experiences in proper management of this system. Currently planning on AMSOIL Signature Series 0w20 using its high PAO and group IV base to offset the high start/cycles and possibly high oil dilution from the DI system. Am I unduly concerned or are these issues not really a problem? Really enjoying the car and the low fuel consumption, drivability is excellent. Looking for some real-world experience with this system. What OCI's should I consider? Liked the Civic so much wife just bought a 2023 Accord Hybrid Sport L Certified Pre-owned with 25,000 miles with essentially the exact same power train.

Oil dilution isn’t mitigated by a brand or by base stocks. It is only helped by increased viscosity and decreased OCI.

 

[Cujet]

You should know that the engine drives the wheels directly via a clutch system. At low speeds the engine is a generator, moderate speeds the engine clutches in and out based on efficiency map settings. At high speeds the drive is most efficient when the engine is driving the wheels directly. There are not multiple gears it is a direct connection, like engaging 5th gear in a 5 speed manual. The engine sees plenty of operating time.

 

[JunkdrawerDog]

Just out of curiosity, what viscosity does Honda recommend? I was wondering whether Honda made the move to 0w-16 on this engine. The previous 2.0 was 0w-20.

 

[Speedy3861]

Oil dilution isn’t mitigated by a brand or by base stocks. It is only helped by increased viscosity and decreased OCI.

Well, I got the decreased OCI's covered, never over 5k, usually 4k or less. I'll probably discuss 0W-30 with my technician next opportunity. He's a fan of 0W-30.

 

[Danh]

Just out of curiosity, what viscosity does Honda recommend? I was wondering whether Honda made the move to 0w-16 on this engine. The previous 2.0 was 0w-20.

0w-20

 

[kschachn]

Well, I got the decreased OCI's covered, never over 5k, usually 4k or less. I'll probably discuss 0W-30 with my technician next opportunity. He's a fan of 0W-30.

The winter rating isn't going to matter either. Any -30 grade is going to react the same way. If you really do have fuel dilution issues I'd use a -40 grade, or an oil with an HT/HS of at least 3.5. Mobil 1 Advanced Fuel Economy 0W-30 is not the same as ESP in the same grade.

 

[jmo42]

I've got an 11th gen 2024 Accord hybrid with a 2.0 liter Atkinson cycle engine and can confirm from UOA that it does have oil dilution issues. It's prompted me to disregarding what the Honda maintenance minder says for OCIs (typically ~7500 miles) and go with a 5k mile maximum OCI to try to flush out as much fuel as I can as early as I can.

I previously used Blackstone for UOA and dilution analysis, but after learning more here on the BITOG forums about how poor Blackstone's fuel testing methodology is, I'm switching over to using Oil Analyzers kits from Amsoil going forward. I strongly suspect that Blackstone under-reported the amount of fuel in my used oil sample.

For now, I'm sticking with Honda's 0w-20 oil recommendations and starting to use Amsoil Hybrid 0w-20 as it's API licensed (and might switch to Amsoil OE for further savings). I want to minimize my headaches on coverage for engine warranty work, especially considering that there are growing reports of the 2.0 liter still blowing head gaskets in this generation of Accord and CR-V, though not as frequently as the 1.5 liter turbo.

The Magnuson-Moss Warranty Act should protect us if we used a thicker oil, but I don't want to have to fight any more than needed with the dealership if my head gasket goes while under warranty. The Honda dealership service departments in my area are already a pain in the backside to deal with under the best of circumstances, which is why I started changing my own oil. I don't want to give them any possible ammunition to use against me on a warranty claim. So instead I'm opting for more frequent OCIs.

 

[Speedy3861]

I've got an 11th gen 2024 Accord hybrid with a 2.0 liter Atkinson cycle engine and can confirm from UOA that it does have oil dilution issues. It's prompted me to disregarding what the Honda maintenance minder says for OCIs (typically ~7500 miles) and go with a 5k mile maximum OCI to try to flush out as much fuel as I can as early as I can.

I previously used Blackstone for UOA and dilution analysis, but after learning more here on the BITOG forums about how poor Blackstone's fuel testing methodology is, I'm switching over to using Oil Analyzers kits from Amsoil going forward. I strongly suspect that Blackstone under-reported the amount of fuel in my used oil sample.

For now, I'm sticking with Honda's 0w-20 oil recommendations and starting to use Amsoil Hybrid 0w-20 as it's API licensed (and might switch to Amsoil OE for further savings). I want to minimize my headaches on coverage for engine warranty work, especially considering that there are growing reports of the 2.0 liter still blowing head gaskets in this generation of Accord and CR-V, though not as frequently as the 1.5 liter turbo.

The Magnuson-Moss Warranty Act should protect us if we used a thicker oil, but I don't want to have to fight any more than needed with the dealership if my head gasket goes while under warranty. The Honda dealership service departments in my area are already a pain in the backside to deal with under the best of circumstances, which is why I started changing my own oil. I don't want to give them any possible ammunition to use against me on a warranty claim. So instead I'm opting for more frequent OCIs.

This is my first hybrid experience after struggling with multiple 1.5t engines so well used to OD issues and like you, have watched Blackstone Labs consistently raise prices without any increase in the accuracy of their results, very disappointed. I'm lucky to have a friendly, professional and competent(and surprisingly ethical)dealer and have been fortunate to meet a Honda Certified Master Technician there who does all my servicing. He's the one who got me into Amsoil and using better filters. They know im kinda pro-active with service so they never try to upsell me. I'm confident Jeff will fill me in on the hybrid mysteries including oil dilution. He has often remarked about high oil levels in every CRV 1.5t he serviced especially those used as "grocery getters". He personally thinks over 5k intervals are creating engines that are ticking time bombs if you intend to keep them longer.

 

[Chief2025]

OK, I now own 2 Honda hybrids with the 2.0 Atkinson engine and some questions have popped up during my thoughts about servicing them.
The Honda Hybrid system essentially uses the ICE as a stationary generator while the car functions primarily as an electric vehicle. The questions I have are:
With the engine operating intermittently to charge the battery, does it ever reach operating temperature? Does the oil reach temperature sufficient to evaporate fuel from the DI system? I know the engineers at Honda are pretty competent and they have undoubtedly considered these issues.
I have never blindly followed the MM system, im probably too proactive but what are thoughts and experiences in proper management of this system. Currently planning on AMSOIL Signature Series 0w20 using its high PAO and group IV base to offset the high start/cycles and possibly high oil dilution from the DI system. Am I unduly concerned or are these issues not really a problem? Really enjoying the car and the low fuel consumption, drivability is excellent. Looking for some real-world experience with this system. What OCI's should I consider? Liked the Civic so much wife just bought a 2023 Accord Hybrid Sport L Certified Pre-owned with 25,000 miles with essentially the exact same power train.

Some Valvoline Restore and Protect to clean those rings and lands.

 

[Speedy3861]

Some Valvoline Restore and Protect to clean those rings and lands.

Well, we backed out of the 23 Accord Sport L hybrid as it was an off-lease vehicle which, according to both Carfax and dealer records had received the bare minimum of service and just looked kinda pigged up and neglected like the people who leased it just took very little care with it. Probably would have looked better after the dealer ran it through the Certified prosess, but overall concerning. Anyways, wife finally settled on a new 2026 Civic Sport Touring hatchback hybrid in Boost Blue Pearl, She loved the color and had enjoyed driving my Sedan, so it made the choice easier. First time in years she's been actually excited about a car and the dealer made us a great deal on it. Didn't want to spend $30 grand on a car we weren't comfortable with and was already 3 years old.

 

[Speedy3861]

Took delivery of the Wife's Civic hybrid Sport Touring hatchback today so now we've got 2 CIVIC hybrids in the driveway, hopefully they will work as well as all our previous Hondas. Mine has been consistantly 46-48 mpg (calculated not the dashboard display) so with gas prices about $4.199 locally that's not too bad.

 

[Faawrenchbndr]

So the 2.0 that is in the Hybrid CRV will run continuously when the vehicle is at highway speeds. I believe anything over 62 mph will be engine driven.

Below 62 and it’s a combination of engine and electrical motor powered.

5k oci at the most, these engines are solid, but the fuel dilution is certainly an issue

 

[wemay]

Oil dilution isn’t mitigated by a brand or by base stocks. It is only helped by increased viscosity and decreased OCI.

Without question, THIS

 

[Pablo]

Toyota didn't execute this particularly well but the aftermarket tunes are great.