[JRHAWK9]

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 [emoji55]

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.

an ounce of prevention is worth a pound of cure. Oil is cheap....except for that magical stuff they put in the CVT!

 

[Dezlpwr]

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.

👍 I agree with you about the stealerships! I was given three free oil changes by my dealer when I took delivery of my '22 Crosstrek. It will never see the inside of a service bay there unless there is a recall or warranty repair needed. I do all of my own maintenance including tire rotations. I don't trust any stealership service tech. Multiple bad experiences in the past from various places over the years is the reason for me, besides saving big bucks.😎

 

[JRHAWK9]

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

I hear ya. I've had the same rhetoric directed towards me in regards to that as well. To each their own though. I do think I may start doing oil filter changes at every other OCI, especially seeing I run the larger 10575 filter due to my Baxter adapter (anti-siphon valve). Seeing this adapter keeps the oil filter full of oil at all times, it has an oil purge valve on it that one must use before spinning the filter off in order to avoid making a big mess. I plan on purging all used oil from the filter those times I do not change the filter. I feel 6,000 miles on a good Fram Titanium is nothing and is what it would be doing if I followed the Subaru's maintenance schedule. We'll see, as I have cases of Titanium 10575's that I got for under $8ea filter. We have two vehicles which take the same filter.

 

[Maldedo]

I may start doing oil filter changes at every other OCI

I was thinking the same thing. Especially since some filters are rated 15-20 000km.

 

[JustSubn]

I'm sure there is something somewhere that I could find on my own, but for the lesser mechanically inclined, how about a step by step detailed how-to for using any of these cleaners? One picture has a hose going into the throttle body -- but how far was it put in? That type of detailed how to I'm talking about... and what about the vacuum port that was mentioned?

Seems pretty straight forward DIY, as long as it's done correctly.

 

[jamesbob]

I'm sure there is something somewhere that I could find on my own, but for the lesser mechanically inclined, how about a step by step detailed how-to for using any of these cleaners? One picture has a hose going into the throttle body -- but how far was it put in? That type of detailed how to I'm talking about... and what about the vacuum port that was mentioned?

Seems pretty straight forward DIY, as long as it's done correctly.

There's a few videos on YouTube. Mr Subaru of course with the OE product. There's another guy who uses the STP. Pretty straightforward. I'm sure there's more out there if you search.

 

[EngineerGeek]

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.

Some direct injected motors are subject to this issue but it's not been a widespread issue with any Subarus. It REALLY only matters if it's causing a significant issue and you don't say that it is? We have 60K on our direct injected FB20D and it runs like the day it was new. It's never had any sort of cleaning. It gets the same great MPG and performs like new. So what's the issue? Yeah other cars, especially German vehicles and some Fords, have had serious carbon issues on intake valves. They throw check engine codes. But that doesn't mean it's a problem for DI Subarus if you're not getting any check engine codes? There doesn't seem to be a genuine problem here, beyond paranoia, unless I'm missing something?

 

[Arthur]

Some direct injected motors are subject to this issue but it's not been a widespread issue with any Subarus. It REALLY only matters if it's causing a significant issue and you don't say that it is? We have 60K on our direct injected FB20D and it runs like the day it was new. It's never had any sort of cleaning. It gets the same great MPG and performs like new. So what's the issue? Yeah other cars, especially German vehicles and some Fords, have had serious carbon issues on intake valves. They throw check engine codes. But that doesn't mean it's a problem for DI Subarus if you're not getting any check engine codes? There doesn't seem to be a genuine problem here, beyond paranoia, unless I'm missing something?

Subaru has released a TSB regarding this issue because it has become a concern as with every other manufacturer using DI technology. Just because there's no check engine code doesn't mean there isn't an issue. Maybe your car runs funny, rough idle, or has a pre-ignition sound when driving but isn't bad enough to trigger the CEL. Should you address those problems before a CEL comes on? I personally would before it becomes something worse.

A significant factor is what kind of fuel you use, oil quality, driving patterns, and how you maintain the vehicle overall. I would say the driving pattern has a significant factor in how carbon builds up. A co-worker of mine has 200,000km on his VW Tiguan and hasn't done a de-carb on it yet. However, his driving style is 90% highway so that helps a lot since his car is at operating temp compared to most city drivers who do short trips and don't allow the engine to reach operating temp.

 

[EngineerGeek]

Subaru has released a TSB regarding this issue because it has become a concern as with every other manufacturer using DI technology. Just because there's no check engine code doesn't mean there isn't an issue. Maybe your car runs funny, rough idle, or has a pre-ignition sound when driving but isn't bad enough to trigger the CEL. Should you address those problems before a CEL comes on? I personally would before it becomes something worse.

A significant factor is what kind of fuel you use, oil quality, driving patterns, and how you maintain the vehicle overall. I would say the driving pattern has a significant factor in how carbon builds up. A co-worker of mine has 200,000km on his VW Tiguan and hasn't done a de-carb on it yet. However, his driving style is 90% highway so that helps a lot since his car is at operating temp compared to most city drivers who do short trips and don't allow the engine to reach operating temp.

The general consensus is what fuel you use makes little difference on a DI engine for carbon build up on the back of the valves as the back of the intake valves never see enough of the fuel to matter. It can make a difference for desposits inside the combustion chamber. What oil you use might make a difference as some oils are more volatile and may send more oil vapors through the PCV system. A premium name brand full synthetic is generally best. And oil change intervals can also matter as the more unwanted substances that build up in the oil the more likely there will be unwanted things ending up in the PCV system. And longer highway drives are always easier on an engine than short city trips especially in cold weather.

The Subaru Service Bulletin involves using Subaru's proprietary diagnostic system to determine if the engine is experiencing misfires above a certain threshold. If not, it instructs the technician to return the vehicle to the owner. Simple as that. If it is experience significant misfires there's a cleaning procedure using their propriety cleaning product and tool.

So my point is the same as Subaru's: If it's not broken don't spend time, money, etc, trying to fix a non-problem. It's not likely there's going to be any harm done in waiting to see if you ever even have an objectively verifiable problem. Modern cars will throw a check engine light with very few misfires which will happen if an intake valve is no longer sealing due to carbon build up. And there's zero risk to damaging things if the check engine light never comes on. So no harm no foul.

There's also a lot of debate if dumping various cleaners into the intake even makes much difference and some cleaners can harm the expensive catalytic converters causing more harm than good. Catch cans may help on some cars but have also been shown to cause issues on others and also tend to void your powertrain warranty. So unless you want to pay for expensive dealer procesures when there are no codes, or objective verifiable issues related to carbon build up, you're best off saving your money and leaving well enough alone. Some car owners like to obsess about things that are rarely a real world problem.

 

[CRAZYHAWK]

I take logs once a year to look for changes that are not great enough to throw a CEL.
EDIAG YA201 OBDII Enhanced Check Engine Code Scanner for cars 1996 & newer | eBay

 

[JustSubn]

Just for the fun of it I took a peek at my throttle body. Wasn't too bad. About 27K on it. That's about the extent of looking at carbon buildup that I can do.

 

[kr_xv]

🤦‍♂️ if people use K&N filter, they have condemned the filter to the grave....my toyota with K&N running for 40k is still much cleaner than that

 

[Cutlass]

A Better Way to Clean GDI Intake Valves | CRC Industries

CRC Industries' CRC GDI IVD® Intake Valve & Turbo Cleaner is a better way to clean GDI intake valves. Clean every 10,000 miles to prevent deposit buildup.

www.crcindustries.com

Was at my mechanic recently and he had fliers out for this product to address the problem. Dunno if it's better or worse than other choices. Just thought I'd pass the info on.

 

[Panelhead]

I went with Crawford Baja AOS early. Remove it and cleaned prior to the four free oil changes. On my own now.
It only had maybe a 1/4 to 1/2 oz of reddish color oil after 6000 miles. Smelled like gasoline. Think it works as designed and drains back into oil sump. Never any water collected.
The lack of water collected I used to attribute to location, right on top of engine block. Figured engine heat was boiling it off. But rethinking this, water is much lower viscosity than oil. Thought is now the water drains out of the heavily baffled can and back into oil sump.
Once there was oil on top of the PCV valve. When pulling the hose oil drained down on block and smelled the oil for a week. Purchased another PCV valve and started rotating them. Would spray with brake cleaner and shake until it rattled freely. Save until next oil change.
Also used MiteyVac Vac to vacuum any oil from hose before pulling off the PCV valve. Never seen oil again. Quit pulling the valve and MiteyVac Vacing the hose.
Figure I will smell it next time I pull the hose.
The AOS is heavily baffled inside. Oil drains slowly for a couple days. A few drops an hour. Then I spray with brake cleaner and let it dry a day or so.
My driving habits hopefully may affect valve deposits too. Have a couple older port injection cars. Drive them usually to go to store or other short trips. Only use Subaru for 20 mile plus round trips. See oil Temperature gets to 200 after less than ten miles. Should boil off the water. At least once a month put go on 700 mile road trip. Oil is still hot, before heading back. Five hours at 200+.
Going to 5K OCI since dealer changes ended. I maintain six cars and all are on 5K. Makes it simple, change at 5000.

 

[adc]

I havbe been doing the treatment every 8K miles on both my foresters

 

[Panelhead]

🤦‍♂️ if people use K&N filter, they have condemned the filter to the grave....my toyota with K&N running for 40k is still much cleaner than that

That is from abrasive cleaning. All silt flowing in is sand blasting the deposits away.

 

[Raybo]

I did the catch can mod (Used these directions: ADD W1 Catch Can install), and my can is 1/4 full of water/oil every oil change. That stuff would otherwise have gone into the air intake and into the TB and valves.
View attachment 311334

Seems like this would work. Have you verified that it made a difference at the intake valves?

 

[Raybo]

Did you use the oil can kit for the Imprezza on a 2.5L Crosstrek? What hose did you buy and use? This is making more sense to me. Does the baffle work as well as the sintered bronze filter some kits use? Further research reveals a catch can is a bad idea if you get freezing temps, which we do here. I like what Arthur said and will see how it goes. Also, an engineer also made some positive remarks.

 

[2021plasmayellow]

Scotty Kilmer uses Lucas through a vacuum line;

Scotty needs to step in front of a bus.

 

[Raybo]

My buddy blew oil out his rear main seal because his PCV lines froze on his truck due to the catch can he used to have on it.

Yes, this can be a problem because it seems most of the liquid is water based and if the crankcase can't vent something will blow out. This might prevent me from doing the catch can here. Seems that Subaru needs to address this problem because this isn't going to help their reputation.