[Prfb25]

Catch cans are NOT present because it increases cost, complexity, liability and not emissions legal.
Just by simply adding a catch can wont make any noticeable difference unless you re-do the whole internal engine ventilation circuit. Want more power, add a electric vacuum pump to remove all that blowby and vent it.

For the build up problem, that is always present on engines, DI or not, SeaFoam or carb cleaner every 25k miles will do wonders.
If you are concerned about thinning oil or water condensation your have other, more serious problems than carbon build up.

 

[JRHAWK9]

It will never be there if we're happy with the current setup. If Subaru monitors groups\forums like this one they might give this problem some consideration. Great car otherwise.

You make it seem that this is only a Subaru issue. It's an issue for all manufactures who have DI only systems.

 

[Raybo]

You make it seem that this is only a Subaru issue. It's an issue for all manufactures who have DI only systems.

Never stated or implied this. This is a Crosstrek forum, so it applies here. We also have a 23 Forester, and it's also a problem for that car. Some manufacturers have addressed this issue, but my concern is that Subaru hasn't addressed it yet.

Found this:
"Which cars have dual injection engines?
Other manufacturers using dual injection systems include Audi, Ford, Hyundai and Nissan. Manufacturers have their own strategies of operation, but in most cases will use port injection at idle. During low to medium loads and engine speed both injectors are used and at high loads direct injection is used."

Toyota also has a solution using the D-4S system.

My 2016 Legacy had port injection and never had a carbon problem and ran fine for 100K miles. Sadly, it was totaled, so I needed a new car. Didn't know the new Subarus adopted this new injection system or that it existed. Oddly, Subaru has no maintenance schedule requirement for servicing DGI specific issues. Hoping I won't have problems and trying to avoid them and why I buy new cars because reliability and safety are number one.

 

[JRHAWK9]

Never stated or implied this. This is a Crosstrek forum, so it applies here. We also have a 23 Forester, and it's also a problem for that car. Some manufacturers have addressed this issue, but my concern is that Subaru hasn't addressed it yet.

Found this:
"Which cars have dual injection engines?
Other manufacturers using dual injection systems include Audi, Ford, Hyundai and Nissan. Manufacturers have their own strategies of operation, but in most cases will use port injection at idle. During low to medium loads and engine speed both injectors are used and at high loads direct injection is used."

Toyota also has a solution using the D-4S system.

My 2016 Legacy had port injection and never had a carbon problem and ran fine for 100K miles. Sadly, it was totaled, so I needed a new car. Didn't know the new Subarus adopted this new injection system or that it existed. Oddly, Subaru has no maintenance schedule requirement for servicing DGI specific issues. Hoping I won't have problems and trying to avoid them and why I buy new cars because reliability and safety are number one.

yep, I know, but until they move to dual injection, it will be an issue for all manufacturers not using it.

 

[kr_xv]

You may have a small oil leak. Once I pulled the hose off the PCV valve and a small amount of oil drained out on the engine block.
Took a couple weeks to burn off. I could smell oil inside and out. I have pulled that hose five or six times and it only had oil in it once. Pulled and cleaned the PCV valve with brake cleaner and made sure it rattles. Never saw oil there again.

so far seems all hose are dry and clean, so not sure what happened yet. the interesting part the smell is more like ad hoc whiff after blasting engine on high rpm and not prolonged smell that is lingering for minutes.

 

[Raybo]

yep, I know, but until they move to dual injection, it will be an issue for all manufacturers not using it.

100% agree.

 

[ecip]

Erg... 63000km on my 2018.. I also figure I'll do that walnut blasting at around 100000km.

Never done an intake valve cleaning using those cleaning fluids. From the videos I've watched and the reports I've read, they dont do much, and a walnut blasting is the way to go once idle gets rough.



I did a quick websearch.. found this stuff here locally. Might give it a try.

MANNOL Intake Valve Cleaner

www.mannol.de

 

[peaty]

My BRZ had the dual injection setup so it's not like they don't have the tec to do it, it comes down to the money. Same thing for the Catch Can also, as mentioned a lot of people are too lazy to empty it. Heck, people ignore the TPMS light.

I think if you do the valve cleaning with something through the TB (I use the STP kit) every say 20K on a new motor and have a catch can it will delay the inevitable. Falls under the better than nothing to me. All of the video's I've seen of them trying to clean a dirty set of valves really doesn't do much. At least the DIY kits. I'm thinking if you start with a new motor you have a little better chance.