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2012 VW GLI
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Discussion Starter #1
Does anyone know if the revised 2019 2.5L engine got switched from Port to Direct Injection, OR if they kept the port injection and then added the direct injection also?
My concern is that I have recently discovered the downfall of cars with ONLY direct injection. I have a 2012 VW Jetta GLI with direct injection. Around 60K miles I started getting cold misfires and general sluggishness in low gears. After doing some research and talking with the VW dealer, I found that since they removed the port injectors (in favor of direct injectors) the valves are getting clogged up with carbon deposits. This wasn't an issue with port injectors as the gas cleaned off the valves when the fuel was sprayed in.
So I opted to pay $750 to get my valves "walnut blasted" to clean off the carbon. Then engine is running good as new again, but I'd like to stay away from cars with only Direct Injection going forward.
I really like the equipment level in the Forester Sport (not really the orange bits though). However, if they switched from port to direct injection, that is probably a deal breaker for me.

Only small SUV I know for sure that has the Dual Injection (port and direct) is the 2019 RAV4. But I drove that and the engine was really loud.
I preferred my Forester test drive, but I have to think about lifetime cost of ownership.

Any insight would be appreciated.
 

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2019 Forester Sport
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2,453 Posts
It is Direct Injection only. The issue with DI engines is widely known and understood. If you don't want DI, then don't buy a Subaru.
 

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2019 Forester
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112 Posts
Came across thread and wanted to ask if this is true is there. A certain gas additive you would put in at a specified mileage or would you use a high octane gas like every third or fourth fill up to prevent clogging ?
 

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2019 Forester Sport
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FALSE! No additive will have any effect on the build up of carbon on a DI engine valve since there is no wash-over of the valve. What you can do, and what I do, is have a service center that uses the BG Products Induction System Cleaner set-up clean out your engine every 30K miles and wipes that carbon buildup right out. Costs about $130-$160 depending upon the shop but does an amazing job. Google BG Products Air Induction Cleaning for more detail. Walnut Shell servicing is necessary when you let the carbon buildup for way too long and is an expensive and unnecessary solution.
 

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@Drew1964 -

The problem with DI is recirculation. Unburned fuel and oil gets recirculated through the intake cycle for efficiency and emissions. The issue is that the droplets "stick" to the back side of the intake valves and then they can't perform as well. It's a gradual thing until it's very noticable. Subaru engineers are aware of the issue and have stated that they've modified the behavior of how the engine runs to minimize this.

Gasoline is an excellent solvent, which in a port-injected car or dual-rail setup will "wash" the back of the intakes and prevent the buildup. However, in direct-injection, it's shot directly into the cylinder, which has many benefits including more horsepower and miles per gallon.

DI is not new technology. Subaru is not the first to do this, so they are aware of the problems and have implemented designs and behaviors to mitigate this.

Your local Subaru dealer will feature something like Carbon Clean or Upper Engine Cleaner if you're concerned.
@bradsechrist - As I mentioned before that DI has benefits including performance and efficiency, so this technology won't be going away. While you could look for a car with a dual-rail setup with both port and direct injectors, there are other issues with them, especially if there's repair work involved. (The amount of labor doubles for any repair work related to injector work according to Toyota)

VW and Audi are notorious for the media shell blasting you mentioned. They were among the first to start using the DI technology years ago. Manufacturers are aware of the problems and tinkering the designs accordingly. There are other things that impact DI buildup, which is why your manual tells you to always get gas from a Top Tier retailer, and always using the appropriate high quality name brand oil.

If you are concerned about the DI in a Forester, you can request an optional service I mentioned above as a preventative measure if nothing else. We don't really know if it's a problem yet, because the FB25 engine just received the DI this year in the Foz. However, Subaru is not new to the direct injection game, as the FA20DIT has been around for a while.
 

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2019 Forester Base CVT
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263 Posts
We also have a 2013 Kia Soul 1.6 Automatic with GDI - just approaching 90K miles and it still runs like new. I've used synthetic oil almost every time, and I believe that reduces the intake "crankcase fumes" deposits on the valves.

Diesels have used direct injection for a century now, and they managed to survive.

Beware of the naysayers.

.
 

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2012 VW GLI
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Discussion Starter #8
thank you all for your insightful comments.
I broached the question with my local dealer and they offered to throw in the Upper Engine cleaning every 30K miles for no charge to alleviate my concern.
Said basically its a can of CRC or Seafoam sprayed into the intake.
Wish VW would have told me about this necessary maintenance when I bought the GLI. I have no problem with the technology, I just want to know what the plan is to deal with the potential side-effects up front.
thanks again.
 

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2018 X3 M40i / 2016 X3 xDrive35i
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Yeah, a can of CRC intake valve cleaner should be an effective way of managing the buildup over time. I'm doing mine every 12k miles (every other oil change) as CRC is recommending every 10k miles. 30k miles might not be quite as effective at curbing buildup.
 

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I am very familiar with both the Subaru method and the BG method as I have had them both done. I can tell you that the BG method is FAR more effective than Subaru's and is a better process to eliminate the carbon. Sure, a can of CRC or SeaFoam will be "ok" but won't do nearly the job of the BG treatment. Just sharing my thoughts.
 

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2018 X3 M40i / 2016 X3 xDrive35i
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@securityguy Are you referencing using those methods after a long interval in trying to remove a significant amount of built up carbon versus using them at the 10k mile intervals and comparing accumulated build up at that point?

I think the point is that there are products that can be used to prevent accumulated buildup versus ignoring the problem until the buildup is there and then you have to consider intervention with a much more aggressive product or technique.

from CRC reference material:
https://www.knowyourparts.com/techn...s-equal-new-service-opportunity-repair-shops/

The regular use of a specialized valve cleaning chemical like the CRC product protects the engine valves from accumulating hard carbon deposits which can break off and cause damage to the engine and other components such as the catalytic converter.

For hard carbon, the service is very time consuming and involves removing the intake manifold to expose the head’s ports and performing a form of soft media blasting, usually walnut shells or plastic beads. The carbon is then removed using a shop vac.
 

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@Scooby24...yes...using the BG method every 30K miles is good practice. I have nothing against using CRC every 10K to keep the deposits light versus significantly building up. I saw a comparison of CRC and SeaFoam and the CRC did a far better job as an "in-between" throttle body/intake service and cheap at that.
 

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Regarding the CRC stuff, from what I’ve read it’s better for preventing the buildup rather than removing the buildup. So that means a more aggressive use interval like every other oil change.

Have heard good things about BG products in general.
 

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2018 Forester 2.5I Prem CVT
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Came across thread and wanted to ask if this is true is there. A certain gas additive you would put in at a specified mileage or would you use a high octane gas like every third or fourth fill up to prevent clogging ?
Running premium only will help if there are fuel dilution issues. Now fuel dilution probably contributes to intake valve deposits as in increase the rate at which they form but eliminating fuel dilution issues probably won't prevent the deposits, either.

Catch cans won't prevent the deposits either.

If you want to avoid DI, grab a 2018 or older FB25.
 

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May not prevent but will certainly help a great deal to reduce the amount of buildup as the oils get caught in the can.
There has been no evidence to support this hypothesis. I get it that it intuitively makes sense but the real world has produced nothing to support it.

I investigated this issue for weeks before I bought a direct injection engine previously. I scoured the internet forums and actually found several examples where people had intake valve deposit issues, cleaned them off, installed a catch can and the deposits still came back. It didn't seem the catch can slowed it down much if at all. There were several examples on the BMW and Mini forums as they had been dealing with the issue longer than most. I believe the VW/audi forums also have some examples of this now days too.

I have my guesses as to why this is. I think the vapors that cause the deposits are too fine for a catch can and just pass right through. I think the vapors that get caught on the catch can are those that were not condensing on the valves and were just burning off anyway.

As long as you don't get water in one, catch can won't hurt anything but I really hate to see people expecting it to improve a situation where it just can't. I think the only surefire method is to remove the PCV system or block it.
 

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2018 X3 M40i / 2016 X3 xDrive35i
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You cannot remove or block the PCV system as you have to release the crankcase pressure. I tend to agree with you I don't think a catch can is the solution. Oil that makes its way back into the intake would stick to the surfaces of the intake and not be accumulating on the valves, I wouldn't think. I'd assume it has more to do with the vaporized oil reflected in NOACK testing which is going to find it's way in back in due to the recirculation of cranckcase gasses. Introduce dirty exhaust fumes from the EGR system when cold and the valves accumulate carbon.

Blocking off the EGR system is probably a much more effective preventative than a catch can.

However...that's a lot of trouble to go through if you can just maintain the buildup with products used once a year or so.
 
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