As Techtron, Seafoam, etc., added to the gas tank won't reach the valves what is the best DIY way to do this? I assume something through air intake? Any suggestions?

The cleaner has to go in through the air intake, either at a vacuum source like a PCV line or brake booster line, or through the throttle body, while the engine is running. I am sure one of these kits will include some method of metering the chemical in so as not to cause the engine to load up and miss or stall or even hydro-lock.

These GDI engines are one time I will recommend the intake system cleaning. It doesn't really do anything for port-fuel-injected engines. Although black goop does build up on the inside of the intake manifold itself, it doesn't hurt anything. If I had a GDI I'd do it probably every 30-50,000 miles. That way you keep it clean to start with and not wait until the carbon causes valves to stick and more drastic measures are needed.

Seafoam with the bent straw for use via air intake.
Link

I’ve become a LiquiMoly fan boy!

https://www.liqui-moly.com/en/...r-p000072.html#20210

Gm has a top engine cleaner that works well, they have a tool for using it but you may be able to use something different, just don't hydro lock the engine.

PDF file :
https://static.nhtsa.gov/odi/t...MC-10161932-9999.pdf

I'd 100% look into getting a proper walnut blasting/cleaning done if you have plenty of miles and you know it's in definite need of cleaning. You are most likely not even going to put a dent in it with any sort of product no matter how you get it through to the valves.

Long story short - if you are due for a clean up get it done right. Squirting cleaner in there is not going to get it done.

Intake Valve Deposits (IVD) in GDI engines are real, and can cause issues. Ford and Toyota created "dual injection" engines with both PFI and GDI injectors because of the IVD.

You are commended for seeking to keep your IVD low.

Another method some have used is a "catch can" between the PCV circuit and the return hose to the manifold. Here, moisture, oil vapor, etc. collect and do not contribute to the IVD.

IVD is a complex chemical reaction, due in part to engine oil and specific engine oil components.

Do good research on use of such spray-in cleaners prior to using one.

One tried and true method is a very slow water injection or introduction into the manifold. This method requires much care. However, in our lab test engine dyno cells, a water cleaning is both working and specified for a particular engine test.

I like CRC GDI Intave Valve Cleaner --> https://www.crcindustries.com/gdi/

My experience as a result of an extremely thorough 'Carbon Clean' of a Audi 4.2L V8, was that PEA was THE Most Effective active ingredient in removing carbon from the Intake Ports/Valves. I used CRC GDI Intake Valve Cleaner (claims highest PEA content!) on the Port Dividers, and in the Intake Ports after the mechanical removal of all of the big stuff, followed by abrasive blasting (w/ walnut shells) in order to clean the back side if the valve stems and low in/on the floor of the port near the valve pocket where Walnut Blasting was not effective.

Due to 'supply chain issues' last summer, the CRC Intake Valve Cleaner was hard to find and I could only get two cans. When I realized was running low (and need to conserve the good stuff!), I bought a can of Sea-Foam, which did absolutely NOTHING on the carbon! By comparison, the CRC seemed to dissolve the 'carbon buildup' compared to the Sea-Foam, and I attribute this to the PEA.

This is a representative Intake Port after the Carbon Clean...



Here's the Engine post 'Carbon Clean' just prior to installing the Fuel Rails and Intake Manifolds...



This particular Direct Injection V8 is prone to Carbon Buildup, so I plan to use it through the Intake at around 175K miles.

I’ll take this opportunity to add a caution about turbocharged engines.

You’re running the real risk of grenading your turbo running cleaners through the engine. Ford has not come up with a chemical solution that they will recommend. They are firmly in the swap heads camp. Do some research if you have a turbo engine.

Good info, thanks guys.
The vehicle I'm concerned about is my 2023 Ridgeline. It only has maybe 6,000 miles on it now but I'd like to stay ahead of it, doing something prior to its next oil change and subsequent ones. Or is every 5,000 miles overkill?
I'll continue to use Techtron on my Corolla which has direct and port injection.

quote:

Originally posted by reflex/deflex64:
You’re running the real risk of grenading your turbo running cleaners through the engine.

How? The cleaner goes directly into the intake, which is after the turbo. When it goes out the exhaust through the turbo it has largely been burned. Perhaps I'm missing something,

quote:

Originally posted by ridewv:
Or is every 5,000 miles overkill?

IMO, way overkill. 30 is more like it.

If you want to stay ahead, use top tier fuel in it.

Do you have Costco by you? They are not only top tier but typically 20-30 cents cheaper per gallon versus other top tier stations such as Mobil, Shell, BP, etc.

quote:

Originally posted by egregore:

quote:

Originally posted by reflex/deflex64:
You’re running the real risk of grenading your turbo running cleaners through the engine.

How? The cleaner goes directly into the intake, which is after the turbo. When it goes out the exhaust through the turbo it has largely been burned. Perhaps I'm missing something,

Backfires and higher than normal temps on turbos that are directly after manifold and carbon chunks are the concern as well as damage to O2 sensors.

Pardon ignorance but would catch cans be useful?

quote:

Originally posted by egregore:

quote:

Originally posted by ridewv:
Or is every 5,000 miles overkill?

IMO, way overkill. 30 is more like it.

OK I may do it every 20K or so but still use Techtron prior to each oil change to help clean the combustion area and top of the pistons.

quote:

Originally posted by Edmond:
If you want to stay ahead, use top tier fuel in it.

I try to buy often use Sheetz or Kroger gas too, probably top tier (Shell or Exxon) 1/2 the fill ups.

quote:

Originally posted by Skins2881:
Backfires and higher than normal temps on turbos that are directly after manifold and carbon chunks are the concern as well as damage to O2 sensors.

Hmm … maybe. If not allowed to get to the point of being encrusted and the cleaner is metered in a controlled manner, I don't see a problem. In any event, if my research is correct, the '23 Ridgeline has a V6 with GDI, but no turbo.

In the Subaru world, catch cans are a fad in the affected model years. However, their usefulness is questionable.

Oil consumption which recirculates to the intake is the problem. That is what cokes the valves. In the USA the recommended oil is 0W-20, but elsewhere is 5W-30. Looking at the temperature ranges for the oil weights shows no worries going thicker except in extreme cold (below about -30 iirc).

So you first of all may not have much problem with valve carbon build up if you aren't consuming oil. You might be able to go to a thicker oil. I was consuming oil with the 0W-20 but not at all with 5W-30. Check your owners manual and research what the factory approves in other countries for the exact same engine.

Another concern with Catch Cans is their use in cold climates. Below 32 degrees F the condensate will freeze, potentially resulting in ZERO crankcase ventilation! This would cause issues, not solve them! As such, winter use in cold(er) climates necessitates being diligent to empty the Catch Can VERY frequently. Also, depending on the vehicle and the available under hood space for mounting, installing one may not be practical. Further, one needs to ensure there no 'traps' exist in the resulting plumbing/hoses if you do install one.

Generally the OEM likely did significant R&D to develop the PCV System, so you need to ensure it's properly maintained and functioning as designed. Any catch can installation would need to be a supplement to that system, and NOT compromise it's function. As such, my research has indicated that if one does install a Catch Can, it should be installed upstream in between the OEM device/PCV and the crankcase vent, NOT downstream in between the PCV and the Intake Manifold. Doing so ensures, the Catch Can reduces the load of the factory PCV and doesn't just handle the overflow. Otherwise your Catch Can won't really be doing much to improve the system until it's no longer functioning properly.

OK, so I'm not afraid to show my ignorance here...

• How does one know that one's engine is a DI?
  
• Can you tell by looking (without removing manifolds, etc.)?
  
• Does "fuel injection" imply DI, or are there other ways to get fuel into cylinders

Yeah, I get that fuel injected engines don't have carbs, but what makes a DI engine a DI engine? Are there code words in a manufacturer's engine description that will reveal this information?