How is this possible in such modern engines? Is gas really that bad? How about other brands, engines? Toyotas? Subarus? Kias

I only buy Chevron techron gas for my Pilot and 93 Costco for my supercharged Tundra truck and turbo bimmer. Both are quality fuels formulas and that comes from someone working in O&G business.

 

too bad u have to remove manifold to even see

 

Carbon build up can be cause by many things. Poor maintenance, gas, bad rings, injectors......just like to have more information on the root cause....Like the comments posted on the Youtube video......this engine has been used on other models...it's "one" of many that had this issue. Hopefully its the case

 

Looks like a VW/Audi 2T that needs walnut blasting every 50k-60k.
And the comment that "this engine has been used in many other" is not true.
The new DOHC was introduced in the Pilot, now used in the Passport, will likely be used in future vehicles replacing the older SOHC VCM engines.
If this owner never did oil changes on time, that is one thing.
If they did 5k oil changes, this will be a problem.
Doubtful a clogged PCV valve is involved at such low mileage.
No D4S like in Toyota engines, so you don't get the benefits of both Port and DI injectors.

Tough to hypothesize on a single occurrence without background, however, I would likely do 4k-5k OCI with R&P or PUP to keep the rings from clogging up, also has a lower Noack to help keep the valve buildup in check.

His comment at the end "time for new heads" doesn't make sense, unless there was a manufacturing defect that caused all of this.
He did comment on this during his most recent Q&A episode 113 that this person was an Uber/Lyft driver, and high amounts of idling may have been a factor.

It would be nice if there was a way to muzzle the new engine, besides using Sport or Tow mode...

 

The new DOHC was introduced in the Pilot, now used in the Passport, will likely be used in future vehicles replacing the older SOHC VCM engines.

No D4S like in Toyota engines, so you don't get the benefits of both Port and DI injectors.

Would the new Honda CR-V have a similar issue? Just got two brand new 2025's for me kids in school and I need to keep an eye on them in case of similar design issues.

 

pretty sure in comments that he said Honda tells him to replace possibly vs cleaning.. and if out of warranty he would clean it.

GDI Top tier should help even though not washing valves..


Although the technology and mechanical equipment for direct fuel injection differs from port fuel injection or carbureted fuel systems, the short answer is the “keep- clean” effect in these fuel systems may not differ greatly. The data and information that the sponsoring engine manufacturers have is not available in the public domain, but AAA conducted an independent investigation comparing the minimum EPA detergent levels to TOP TIER™ Approved Gasoline. The full report is available for free download here. AAA did a great job showing where in the engine you can benefit from gasoline meeting the TOP TIER™ Performance Standard and even commented on GDI engines (see section 2 of their report on pages 9 and 10; and the sub-section on emissions found in section 5.3 – page 19).

AAA: Not All Gasoline Created Equal

Tests show quality gasoline keeps engines 19 times cleaner

newsroom.aaa.com

 

Yes I agree Top Tier has a minimum number of detergents to help with injector, combustion chamber cleaning - or keeping it clean.

The issue lies where this detergent/gas is no longer contacting the back side of the intake valves to clean them, this can cause carbon build up from the PVC system. The PCV system is there to prevent engine seals blowing out from the pressure generated in the engine from the moving parts. Early generations of DI engines suffered from carbon build up. We have knowledge and technology now, it's rather does the manufacturer want to implement new technology. Some manufacturers implement an additional injector into the intake stream which acts similar to port injection which washes/cleans the back side of the valves. But there's the additional cost of research & development. Like how Porsche has their ignition key in the left side because it saved on copper (wires) from shorter wires which saved them money.

 

Read the part about how it helps gdi.

i understand why it occurs.

 

Their sentence structure is misleading, "Without detergent additive packages, the carbon deposits can readily form
on the intake valves, in the combustion chamber and on the injector tip of gasoline direct injection (GDI)
engines."

It's talking about 2 engine designs in 1 sentence. The whole sentence is true for Port Side Injection, second part after comma is true for Direct Injection.

Look at the illustration and caption on both pages, page 9 caption and illustration shows fuel spraying over intake valves. Page 10 says DI sprays fuel directly into combustion chamber. It is also talking about carbon build up in general which also builds up on top of pistons. I've seen a car from a grandma driving and using cheap gas. Car wouldn't start because the plugs were so fouled over with carbon deposits there was no electrode gap. This was back in the early 90s.

 

Again..i understand how it works..it is still incremental improvement… less contamination in oil to start with.

 

Agree, shorten the oil change interval with a quality full synthetic with a low Noack rating. Use top tier gasoline (87 octane) at Chevron, Exxon, Mobil or Shell, fuels with PEA or use a PEA fuel treatment. I’d hope at some point someone will figure out how to permanently disable the VCM, otherwise I’ll never own a 4th gen.

 

So one thing that's very interesting about European car manufacturers is that they love to publish details about all the changes they made with regards to engine technology and why they made that choice, etc. BMW and VW tech docs tend to be excellent. You may not agree with their logic, but it sure is interesting to try to understand it.

What is very interesting is the VW / Audi had <major> carbon build up issues on their EA888 Generation 2 engines. With their EA888 Generation 3 (and newer) engines they seemed to have massively reduced carbon build up on the intake valves. The engine block didn't really change, they're still just using direct injection in the US, but somehow, the problem isn't really a big problem anymore. If you get to reading, you see they added a modified "Miller Cycle" to the newer engines and specifically describe what the Miller Cycle is:

Sooooo - now we potentially have fuel coming OUT of the cylinder with a DI engine and back into the intake manifold in certain situations. Fuel with additives that could help keep those valves cleaner. Not a clean as port injection, but no longer the nightmare that DI can be. Seems to correlate to me.

Moving on to Honda - I recall one of the Honda techs on here indicating that Honda may have been doing some things with intake valve timing (maybe a modified Atkinson cycle) that caused reduced build up on the 3rd gen Pilots which are NOT known for carbon build up. Makes me wonder if Honda changed the intake valve timing to a different logic with the 4th generation Pilot. Was Honda letting some fuel swirl outside of the cylinder in the 3rd gen Pilot? Makes me think they might have been....



For anyone like me who likes to read technical stuff.... here are the VW / Audi docs I pulled the Miller Cycle info from that also explains when / how they apply it, etc. Not exactly "Honda" stuff, but potentially interesting:

https://static.nhtsa.gov/odi/tsbs/2016/SB-10105867-2280.pdf

https://static.nhtsa.gov/odi/tsbs/2014/MC-10122162-9999.pdf

 

Moving on to Honda - I recall one of the Honda techs on here indicating that Honda may have been doing some things with intake valve timing (maybe a modified Atkinson cycle) that caused reduced build up on the 3rd gen Pilots which are NOT known for carbon build up. Makes me wonder if Honda changed the intake valve timing to a different logic with the 4th generation Pilot. Was Honda letting some fuel swirl outside of the cylinder in the 3rd gen Pilot? Makes me think they might have been....

I mean if we're being honest, this new DOHC J series engine aside, Honda's GDI engines as a whole have not been known to develop significant carbon buildup on the valves, at least to date. So clearly they were doing something right.

 

23 pilot.. 100k...all good... new J series.. cant wait for timing belt video..

 

That's straight up bad gas. If you can, drive the next 5 fill ups with Costco gas

 

These stores selling gasoline like Sam’s, Costco, QT, Buckies, Stripes, Seven Eleven etc that do not advertise a brand, can we trust that they have a quality additive package, if any?

 

Non ethanol gas helps. List of stations on pure-gas.org
ONLY gas me and friends use. Helps a lot and better MPG. YES 100% gas cost more but worth it. Of coarse VCM bypass is a given. Ktuner helped 09-15. Update was 10.9.6.
Pulled my VCM Bypass and Ktuner V2 before insurance took car.

 

Yes we're blessed to have a pure gas station here in Texas, but it's 22 miles away. I've noticed non- ethanol gas at some Walmart, AKA Murphy's gas stations. The extra MPG helps to compensate for some of the price difference, longer engine life pays for the rest.

 

They pop up everywhere now a days. pure-gas.org is user fed so we help list and correct as stations come and go. Glad Whitelightning gets NON Ethanol
I'm lucky 2 new Allsups a new Murphys and new Maverik (with 88 and only 1.2 miles from house also $3.15 a gal today but fair is in town). Other 3 are 86 Octane.

 

This is very disturbing…. I’m going to install a Mishimoto oil catch can on my 2025 Pilot @14k miles. Still waiting for a VCM Muzzler that works on the new 3.5L DOHC V6. I did that on my 2015 Odyssey and it cured my P0303 problem. I‘m now wondering if I should have bought a Toyota Highlander instead. 😜

What a choice: Toyota 2.4L 4 cylinder Turbo with DS4 or ….Honda 3.5L NA 6 cylinder with GDI & stupid VCM.

Pick your poison … Thanks EPA! 🖕

 

I‘m now wondering if I should have bought a Toyota Highlander instead

It's not too late to trade your Pilot in on one. 😆

#chickenlittle
#theskyisfalling

 

In the grand scheme of things, I believe Toyota and Honda are still the most reliable brands. They’re not perfect, but they’re more dependable than most of the competition. I have several Toyotas and Hondas in my garage, and after 30–40 years, I can confidently say the money was well spent. Aside from routine maintenance and a few sensible upgrades, I’ve never had to spend extra due to reliability issues. Every one of them has been rock solid.

I have some 1075,1976, and 1977 Hon

In the grand scheme of things, I believe Toyota and Honda are still the most reliable brands. They’re not perfect, but they’re more dependable than most of the competition. I have several Toyotas and Hondas in my garage, and after 30–40 years, I can confidently say the money was well spent. Aside from routine maintenance and a few sensible upgrades, I’ve never had to spend extra due to reliability issues. Every one of them has been rock solid.

I agree.
I have some 1975,1976, and 1977 Honda Gold Wing motorcycles in my shop right now. Every one of them will start right up and run down the road. The only reason I don't ride them more often is that my 2007 Honda Gold Wing Air bag model has all of the bells and whistles with large side boxes and trunk that makes it much more comfortable for my 1,000+ mile trips. Every one of them is rock solid reliable. But modern bikes are so much more comfortable than the old ones, just like today's civic is so much more comfortable than the 1973 model. But reliability is still their goal.

 

Never had a gold wing. My BMW I was scared if ever needed any work so sold it but very nice smooth ride. Missed out on neighbor/friend selling 85 or 86 Honda V65 Magna but scared me cause he did over 200 mph on it & I'd hurt myself.
Had a 03 now 07 Suzuki Burgman 650. My 96 Suzuki DR650SE was stolen by neighborhood methhead in middle of night.
Flood took 5 of my vehicles including 03 Burgman & son driving Pilot in flood was another. Full coverage with new car replacement.
Enjoy 04 Chevy truck 4.3L, 05 Accord 2.4L Ktuned, 00 Insight or 08 Civic Hybrid but My 04 Saturn Vue V6 AWD with 225K has Pilot power train & 1K lbs lighter with CAI. Yes lube issues on transmission in early 2000, Accord also, so Saturn had MJ8 transmission rebuilt. Saturn didn't think of better cooling cap like simple transmission cooler. Accord has RV transmission cooler.
Both Accord and Truck had been stolen in Albuquerque before I brought them. Why Mr Yellowhorse was selling truck with 1 yr reman transmission he was tired of thieves stealing it in front of his house.

 

I have a 2025 Honda Pilot. After watching the oil guy geek videos and emailing Valvoline, I do the following to hopefully avoid carbon build and protect fuel injectors.

Change oil every 3K miles, NOT 5k or 10k.
Use Valvoline restore and protect synthetic oil - it is not just for old cars.
With every oil change, use Chevron Techron fuel additive to clean injectors.
Use only top tier gas. I use Costco.

Per Valvoline, the additive pkg in their restore and protect oil that removes/prevents carbon buildup travels with the oil mist passing through the PCV valve. This should help prevent carbon build on top of the intake valves. Also, any oil leaking past the seals on the intake valve rods will also contain the additives preventing that oil from carbonizing on top of the valves.

Keeping fuel injectors functioning properly by using top tier fuel and chevron techron fuel additive will also help prevent carbon build on the valves. When fuel injectors are not functioning properly, there is an increased risk of fuel dilution in the oil, which increases the amount of oil mist passing through the PCV valve, which increases the amount of oil seeing the tops of the intake valves.

I am not a fan of GDI engines. I hope to be able to disable the VCM soon which would also help reduce risk of carbon buildup. Please post if news comes out that they have come up with a VCM disabler for 2025 Pilots.

 

Yes, that's why I test my oil. My benchmark has always been one % FD drain it. The engine manufacturers said up to 3% Fuel Dilution is fine. I'll stick to 1%, but since the first oil change with V R&P I haven't come close to even 1% .