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Discussion Starter · #1 · (Edited)
Hey guys, I've been looking all over the internet for photos of carbon build-up on the intake valves on our 18+ Crosstreks since we have direct fuel injection with the FB20D.

I was curious to see how much build-up I have on my intake valves so I decided to remove the intake manifold to inspect. I have just under 50,000km (30k miles), mostly city driven (70% city/30% highway), and I do my oil changes more frequently than the average owner at 5k intervals.

I've had a fuel induction completed at the dealership at 18,000km (11k miles) and 36,000km (18k miles). The first induction cleaning the dealership used two bottles and when I did it myself I used two bottles as well. It's hard to say how much of a difference those induction cleaning did to the intake valves because I don't have a before and after to compare... I was expecting a lot worse and was planning to walnut blast but I will do an induction cleaning once a year and see how things look at 100,000km (60k miles).

I know there's another thread regarding this topic so if the Mods want to merge the thread into a super thread, feel free to do so. I guess we can use mine as a starting point since I have photos and more owners can add to this topic with their findings/pictures.

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Discussion Starter · #3 ·
Nasty looking. I've been thinking about doing this myself on my 2019. CRC makes a good intake valve cleaner.
I have the Subaru upper engine cleaner tool that I got from the US. It works really well but I have no experience with CRC. The only upside to seeing what my valves look like is it's possible to clean using the induction cleaning since it's not super caked in yet.
 

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2021 Ice SIlver Sport
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Wow! If it looks that bad at 30k, just imagine at 100K! I'm in shock how bad it looks for such low miles. I guess the built in PCV oil separator doesn't work to well? A lot of the newest designed DI engines now add a little bit of fuel through the intake runners for wash to try and prevent this.

Be sure to post your results if you use the cleaner tool. What a pain though as you'd have to take the intake back off again to see how much it cleaned things up.
 

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Discussion Starter · #5 ·
Wow! If it looks that bad at 30k, just imagine at 100K! I'm in shock how bad it looks for such low miles. I guess the built in PCV oil separator doesn't work to well? A lot of the newest designed DI engines now add a little bit of fuel through the intake runners for wash to try and prevent this.

Be sure to post your results if you use the cleaner tool. What a pain though as you'd have to take the intake back off again to see how much it cleaned things up.
I know at VW they don't get bad until you're into the 100k mark (60k miles) but I also took it apart to see if it was really bad because I have a rough idle and it's noticeable at idling at a stoplight but if I lift my foot off the brake pedal slightly it raises the rev and it goes away.

I couldn't really clean out the TGVs but I was able to clean out the intake plates and throttle body, it has improved a bit but it's still noticeable but not as bad as before.

I'll update the thread again when I'm at 100,000km to compare it with the once-a-year induction cleaning I plan on doing.
 

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Hey guys, I've been looking all over the internet for photos of carbon build-up on the intake valves on our 18+ Crosstreks since we have direct fuel injection with the FB20D.

I was curious to see how much build-up I have on my intake valves so I decided to remove the intake manifold to inspect. I have just under 50,000km (30k miles), mostly city driven (70% city/30% highway), and I do my oil changes more frequently than the average owner at 5k intervals.

I've had a fuel induction completed at the dealership at 18,000km (11k miles) and 36,000km (18k miles). The first induction cleaning the dealership used two bottles and when I did it myself I used two bottles as well. It's hard to say how much of a difference those induction cleaning did to the intake valves because I don't have a before and after to compare... I was expecting a lot worse and was planning to walnut blast but I will do an induction cleaning once a year and see how things look at 100,000km (60k miles).

I know there's another thread regarding this topic so if the Mods want to merge the thread into a super thread, feel free to do so. I guess we can use mine as a starting point since I have photos and more owners can add in to this topic with their finds/pictures.

View attachment 311313 View attachment 311314 View attachment 311315 View attachment 311316

Those are some ugly looking valves. I know a lot of people were concerned when that engine first came out. But I didn't expect that.
 
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Discussion Starter · #9 ·
Is it possible to shove a borescope via the intake path to have a look at them without removing the TB?
No, the TGV flaps will get in the way because they're semi-closed. When I mean semi-closed I mean closed with a slight gap that's impossible to fit anything through besides a coin, and the intake plates take up a good portion of the room so you gotta remove everything.
 

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Discussion Starter · #10 ·
Is it possible to shove a borescope via the intake path to have a look at them without removing the TB?
I know the image quality isn't the best but this is what I got. The plate sticks out a bit because it goes in at a slight angle then the part that sticks out is straight. The TGV isn't too far away from that plate and tumbles the air as you drive/operate during a cold start. So you'll have a hard time getting a borescope in there.

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I really appreciate and hate this. Didn’t expect it to be so bad for the mileage. This has been my biggest issue with consideration for direct injection only vehicles. Knowing it looks like this means i won’t wait until 36k to do it. Upside being the intake holes facing up so easy walnut cleaning if warranted!
Edit: also going to be on cleaning the pcv valve more often
 

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Discussion Starter · #12 ·
I really appreciate and hate this. Didn’t expect it to be so bad for the mileage. This has been my biggest issue with consideration for direct injection only vehicles. Knowing it looks like this means i won’t wait until 36k to do it. Upside being the intake holes facing up so easy walnut cleaning if warranted!
Edit: also going to be on cleaning the pcv valve more often
Not sure if you've started looking but I know they make an adaptor to make walnut blasting easier for other cars like VW/Audi products. I hope someone could make one for the FB series engine. I know there's one available for the FA20 but not sure if it'll work for the FB engines.

Is it cheaper to clean the PCV valve instead of replacing it?
 

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Hey guys, I've been looking all over the internet for photos of carbon build-up on the intake valves on our 18+ Crosstreks since we have direct fuel injection with the FB20D.

I was curious to see how much build-up I have on my intake valves so I decided to remove the intake manifold to inspect. I have just under 50,000km (30k miles), mostly city driven (70% city/30% highway), and I do my oil changes more frequently than the average owner at 5k intervals.

I've had a fuel induction completed at the dealership at 18,000km (11k miles) and 36,000km (18k miles). The first induction cleaning the dealership used two bottles and when I did it myself I used two bottles as well. It's hard to say how much of a difference those induction cleaning did to the intake valves because I don't have a before and after to compare... I was expecting a lot worse and was planning to walnut blast but I will do an induction cleaning once a year and see how things look at 100,000km (60k miles).

I know there's another thread regarding this topic so if the Mods want to merge the thread into a super thread, feel free to do so. I guess we can use mine as a starting point since I have photos and more owners can add to this topic with their findings/pictures.

View attachment 311313 View attachment 311314 View attachment 311315 View attachment 311316 View attachment 311325 View attachment 311326
This answer many skepticism on Catch can and regular PEA cleaning, waiting for more pictures from car with catch can installed
 

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Interesting, thanks for posting this. At 18k, the family's MY18 is dead smooth at a stop light now(IE barely notice it running). I'll be interested to see what things look like inside when I pull the intake, especially after using techron annually. The car will probably need motor and trans mounts in a couple years(cvt hard on the mounts).
regards
 
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