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2022 Crosstrek Premium 6 Speed MT
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Ha! Yeah I saw that. I failed to mention that i am switching to Oil Analyzers for this very reason. I have one Blackstone pre paid sample kit left and six prepaid Oil Analyzers so hopefully I got erroneous fuel dilution info from them. It was only 1.3%, below the 2% "caution" mark, but there was only 2,000mi on the oil. It was the second oil change since new to wash out wear in metals.
 

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2022 Crosstrek Premium 6 Speed MT
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109 Posts
It is concerning though that Blackstone fuel dilution numbers often are low, according to those links, so I may have had more fuel in the oil?馃槼. Doubtful though, because my oil level remained right at the full mark the entire time.
 

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2021 Crosstrek Limited
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717 Posts
I'm doing 3,000 mile OCI's (with the latest API oil) with a bottle of Redline SI-1 in the gas tank (only use Top Tier fuel) before every oil change and then yearly CRC/Berryman cleanings. I'm hoping everything combined will help keep intake valve deposits and combustion chamber deposits in check. I have no idea if it will though.
 

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2021 Crosstrek Limited
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717 Posts
It is concerning though that Blackstone fuel dilution numbers often are low, according to those links, so I may have had more fuel in the oil?馃槼. Doubtful though, because my oil level remained right at the full mark the entire time.
Nothing one can do if they are, except change the oil regularly....which is why I will be doing so on both our new GDI vehicles.
 

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2022 Crosstrek Premium 6 Speed MT
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109 Posts
I'm doing 3,000 mile OCI's (with the latest API oil) with a bottle of Redline SI-1 in the gas tank (only use Top Tier fuel) before every oil change and then yearly CRC/Berryman cleanings. I'm hoping everything combined will help keep intake valve deposits and combustion chamber deposits in check. I have no idea if it will though.
Sounds like a good plan to me! 馃憤 I will most likely be doing similar. I'm going to be doing a 3,000 mi interval oil change next soon so we'll see how the analysis comes back from that, but most likely I will do 3-4K intervals. Wife does a fair amount of short trips and I know this can increase fuel dilution in these engines.
 

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2021 Crosstrek Limited
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'23 Limited
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114 Posts
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
Excellent pics and details! Thanks for posting this!

I must have read this thread 4 times already, LOL. Typical over-thinker here had me worried at first (I have a Limited coming next week).

I will say, it's not horrible for the type of driving you do, city driving is apparently really bad for DI.

Most importantly though, it looks super easy to mechanically clean! Straight up and down ports that sit on the very top of the engine. Even manually cranking the engine to open/close the valves is easy, being that the boxer sits front to back, unlike an FWD. I had a 2017 WRX that while similar, has more to remove to get the same access.

I don't even think you would necessarily need to do a walnut blasting, there are other DIY methods that also work. I saw a vid of a guy using zip ties and the end of a drill. Looked funny but worked without being too abrasive.
I saw someone else using a soak method with a 50/50 mix of brake cleaner and CRC. After an hour, he sops up the fluid with some shop towels, carefully navigating them with a screwdriver. I was amazed at how much came off.

Anyways, I think it's not the end of the world. Aside from this issue (which is a DIY fix), these engines (both the FB20 & FB25) seem to be quite reliable.
 

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'23 Limited
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114 Posts
Not sure if this will help. Seems pretty thorough.

Yeah, I don't think Subaru does these anymore, something about not trusting the techs and accidentally blowing the engine up. It's basically the same as the CRC induction cleaner or STP or BG. Any one of those every 10 to 15,000 mi would be helpful as a preventative thing
 

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2019 Subaru Crosstrek Limited
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Discussion Starter · #72 ·
Yeah, I don't think Subaru does these anymore, something about not trusting the techs and accidentally blowing the engine up. It's basically the same as the CRC induction cleaner or STP or BG. Any one of those every 10 to 15,000 mi would be helpful as a preventative thing
If the techs blow it up, they have shop insurance to cover something like that.
 

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XV Crosstrek 2014 Premium 2.0i 6MT
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179 Posts
It's ''nice'' to see what the actual buildup in one of our engines looks like. I am wondering if anybody has insight on how much the exhaust gaz recirculation(EGR) contributes to the carbon build up in the intake?

I think this could have a much bigger impact than the couple drops of oil that a catch can collects over thousands of kilometers... If anyone has done an EGR delete on a GDI model and is willing to take pictures for comparison, that would be great!
 

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'23 Limited
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114 Posts
It's ''nice'' to see what the actual buildup in one of our engines looks like. I am wondering if anybody has insight on how much the exhaust gaz recirculation(EGR) contributes to the carbon build up in the intake?

I think this could have a much bigger impact than the couple drops of oil that a catch can collects over thousands of kilometers... If anyone has done an EGR delete on a GDI model and is willing to take pictures for comparison, that would be great!
You should go over to the WRX community, that's a much more common modification for them. TGV EGR delete. And they suffer from carbon worse than us N/A guys do.

I spoke with a Subaru tech outside of his work environment. He did a walnut blast at 30K for his mother's Forrester. He told me he was surprised that how much build-up there was.

So your best bet is to do an induction cleaning every 25k at a minimum, and prepare for an eventual walnut blasting / DIY cleaning. This is what the tech told me. He also told me to ignore Subaru's 6K mileage oil change interval, wait no longer than 4K. And off topic, he told me to change out the CVT fluid every 50k at a minimum.
 

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XV Crosstrek 2014 Premium 2.0i 6MT
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So your best bet is to do an induction cleaning every 25k at a minimum, and prepare for an eventual walnut blasting / DIY cleaning. This is what the tech told me. He also told me to ignore Subaru's 6K mileage oil change interval, wait no longer than 4K. And off topic, he told me to change out the CVT fluid every 50k at a minimum.
Good advice, my local subaru specialist told me pretty much the same thing.
 

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2022 Crosstrek Premium 6 Speed MT
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109 Posts
You should go over to the WRX community, that's a much more common modification for them. TGV EGR delete. And they suffer from carbon worse than us N/A guys do.

I spoke with a Subaru tech outside of his work environment. He did a walnut blast at 30K for his mother's Forrester. He told me he was surprised that how much build-up there was.

So your best bet is to do an induction cleaning every 25k at a minimum, and prepare for an eventual walnut blasting / DIY cleaning. This is what the tech told me. He also told me to ignore Subaru's 6K mileage oil change interval, wait no longer than 4K. And off topic, he told me to change out the CVT fluid every 50k at a minimum.
I change my oil at 3k. Was going to go longer but I'm seeing 2.4% fuel dilution on my oil analysis when I changed the oil at 3k. Oil is cheap in the grand scheme of things so I'm playing it safe. I believe that the EGRs plug up the intake valves worse than the CCV. I'm running a catch can, which should help some but I'm sure (others vehemently disagree on here that catch cans provide any benefit 馃槀)I'm going to need to do some intake valve cleaning at some point down the road.
 

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2022 Crosstrek Premium 6 Speed MT
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You should go over to the WRX community, that's a much more common modification for them. TGV EGR delete. And they suffer from carbon worse than us N/A guys do.

I spoke with a Subaru tech outside of his work environment. He did a walnut blast at 30K for his mother's Forrester. He told me he was surprised that how much build-up there was.

So your best bet is to do an induction cleaning every 25k at a minimum, and prepare for an eventual walnut blasting / DIY cleaning. This is what the tech told me. He also told me to ignore Subaru's 6K mileage oil change interval, wait no longer than 4K. And off topic, he told me to change out the CVT fluid every 50k at a minimum.
So local Subaru dealers still do the induction cleaning?馃槼
 

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'23 Limited
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114 Posts
So local Subaru dealers still do the induction cleaning?
Not sure. I didn't ask the guy if his dealership does the induction cleaning service. He was giving me advice in general and not really about going to the dealer to get anything done in particular.

Regardless, I would probably do the induction service myself with one of the aftermarket products. Same as the CVT fluid change, I'm definitely going to do that myself.

I honestly don't trust dealerships and the guys that turn wrenches over there. I'm super hesitant to even have them do oil changes even though I get one year for free, lol.
 

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2021 Crosstrek Limited
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So your best bet is to do an induction cleaning every 25k at a minimum, and prepare for an eventual walnut blasting / DIY cleaning. This is what the tech told me. He also told me to ignore Subaru's 6K mileage oil change interval, wait no longer than 4K. And off topic, he told me to change out the CVT fluid every 50k at a minimum.
Good advice, my local subaru specialist told me pretty much the same thing.
Ditto....I'm doing 3K oil changes and planning on CVTF changes every 20-30K and yearly CRC induction cleanings (~10,000 miles). Already did my first one at ~7K.
 

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'23 Limited
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114 Posts
I change my oil at 3k. Was going to go longer but I'm seeing 2.4% fuel dilution on my oil analysis when I changed the oil at 3k. Oil is cheap in the grand scheme of things so I'm playing it safe. I believe that the EGRs plug up the intake valves worse than the CCV. I'm running a catch can, which should help some but I'm sure (others vehemently disagree on here that catch cans provide any benefit )I'm going to need to do some intake valve cleaning at some point down the road.
Ditto....I'm doing 3K oil changes and planning on CVTF changes every 20-30K and yearly CRC induction cleanings (~10,000 miles). Already did my first one at ~7K.
100% agree on the 3K oil changes. I usually don't say that out loud because people think it's crazy these days to do such a frequent OCI

Ever since My first DI car, I've been super vigilant about this. When I had a 2017 WRX, I could smell the fuel on the dipstick, something I've never encountered before. Scared the crap out of me.
 
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