It is Honda's turn to handle head gasket problems on new dual motor hybrid design introduced in 2023. https://www.go-parts.com/garage/engine-cylinder-head-honda-civic-honda-accord-honda-cr-v-2023-2025?srsltid=AfmBOoqm5I38lGu-zCmkyKWlZopEBI74YjciMM21KhzpyossbcTy9tke
it amazes me that these geniuses can't get it right. it must be the bean counters, the engineers can't be this bad
It's the first twin electric motor for Honda who did not license Toyota technology likeFord did. Thermal cycling that was not present in Otto port injected versions of the engine is the likely cause as is the most logical case with gen3.
They went from a naturally aspirated engine to a direct inject; turbo charged engine. Engine start/stop systems probably compounds matters. Higher pressures and heat spots contribute to the issues along with customers that have a closed hood policy. I'm paying someone to maintain the car; so I don't need to check anything. Just my take on things. They're making it out of the warranty period, just doesn't meet customer expectations; which are very high - considering the cost of new cars these days.
It isn't their first power-split hybrid system. It first showed up in the previous generation Accord and the Insight3. And Toyota licensed Ford emission controls that they really wanted. The reality was that Ford developed their system independently. Toyota just beat them to the patent office. And they both ended up paying Paice. No turbo in the hybrid. "The primary cause is suspected to be the frequent on-and-off cycling of the gasoline engine in a hybrid system. This repeated heating and cooling (thermal cycling) puts significant stress on the head gasket, potentially causing it to fail much earlier than expected." Guessing the direct injected engine that showed up in the 2023 Accord runs hotter.
Thermal cycling is caused by the rapid loss of temperature when the engine shuts off in Ready which returns when it restarts. I have seen 40 degrees drop when in traffic or when "idling".
The 1.5L and 2.0L engines are having head gasket issues; not just on the hybrids. They have been known to make those size engines to be bullet-proof in the past - w/o head gasket issues. The differences I noted above (#4); no issues with intake manifold fuel injection on those same engines in the past. For clarification purposes; Hondas first gen hybrids wasn't a power split unit. They simply removed the torque converter and placed an electric helper motor; so the engine needs to run to move the car. IMA, integrated motor assist. The engine was downsized and optimized; that's why they were never able to achieve the same numbers as a Prius, though they were as gutless as a Prius. Honda later copied/engineered a similar Toyota's setup. Honda did beat Toyota to the marketplace with the first mass production hybrid; Honda Insight. For the record; those engines didn't pop head gaskets and they also turned-off the engine when stopped. I believe I had a 1.3L in that old Civic hybrid. Lost the traction battery around 75K miles - replace under warranty; sold it and bought my first Prius.
Honda can only claim first hybrid in North America as it arrived a year before the Prius as a 2000MY. Toyota had been mass producing the Prius in Japan since 1996. IMA was just a mild hybrid system, and it was likely rushed going by the battery issues some models had. Honda does have another full hybrid besides the power-split multimode; well, they actually claim two. It is a parallel hybrid similar to Hyundai's, Toyota's Hybrid Max, and others. It arrived before the power-split in the Jazz/Fit hybrid, which managed to outsell the Prius in Japan for a bit. Then Honda made a performance version of it with two motors on the rear for AWD. I think we got an Acura with it at one time. On the OT, how new are these engine designs? Total redesign, or just the previous model modified to have direct injection?
