I saw this video yesterday. He went into detail on how it works, and it was a good thing he mentioned how you can cause damage if done incorrectly.

 

I wonder if there is really a need for this?
Tell me why it should be done.

 

It depends on your approach for solving the issue, save cost till it happens and may have more downtime, or prevent it from happening and prolong as much as possible before requiring downtime. There is no right and wrong answer, it is up to individual mindset

 

thanks, kr.
I do not know what the issue is.

 

The issue is engine pinging, sluggish acceleration and for those have sensitive ears, noisier engine.

 

This does not address the worst problem...carbon buildup under the intake valves. I use CRC intake valve cleaner every 10,000 miles.

 

The Subaru top engine cleaner is supposed to do what CRC intake valve cleaner does, but as its effectiveness of liquid and foam, so far I never see any documentation showing which one is better.

 

How effective are such automotive store valve cleaners when you spray them so far ahead of the valves? Won't it just coat the inner air track surface without really reaching where it should?

 

All the PEA-based cleaner documentation points to more effectiveness with heatsoaking, so for CRC they recommend to heat-soak the engine at least for 1 hour after spraying it with the cleaner to have better results. Their documentation shows some carbon even being removed up till 1 week after application.
My personal regime involves using PEA based fuel system cleaner in the tank a few days before and after using CRC intake valve cleaner (that is similar to any 3-step carbon cleaner kits), as well as spirited driving after application, that I find effective address the sluggishness, noise even though I seldom put boroscope inside to take picture.

 

For what it's worth, my dealer did the full carbon cleaning prior to flashing the ECU (due to the 2500 rpm hesitation caused by a false knock reading). No perceptible effect whatsoever.
Now that I think of it though, I have a cheap smartphone-connected endoscope, so I might shove it up the engine's intake and see how the valves look like..

 

Now that I think of it though, I have a cheap smartphone-connected endoscope, so I might shove it up the engine's intake and see how the valves look like..

And this managed to slip your mind?

 

Another thing to be aware of is that Mr. Subaru's vehicle is the First Generation Crosstrek that uses the Port Fuel Injection system and not the Second Gen (2018+) that uses a Direct Injection system.
Completely different problems separate those two fuel delivery systems.
This system probably works as advertised in the First Generation, but I suspect not so much in the Second Gen.
The Second Generations Direct Injection system leaves the backside of the intake valves vulnerable to carbon build-up, that this type of intake manifold spray cleaner delivery system does not address.
As far as I know, the only proven way to remove this carbon buildup in a DI system is a mechanical cleaning.

 

Another thing to be aware of is that Mr. Subaru's vehicle is the First Generation Crosstrek that uses the Port Fuel Injection system and not the Second Gen (2018+) that uses a Direct Injection system.
Completely different problems separate those two fuel delivery systems.
This system probably works as advertised in the First Generation, but I suspect not so much in the Second Gen.
The Second Generations Direct Injection system leaves the backside of the intake valves vulnerable to carbon build-up, that this type of intake manifold spray cleaner delivery system does not address.
As far as I know, the only proven way to remove this carbon buildup in a DI system is a mechanical cleaning.

It's weird because the TSB associated with that tool only applies to 2nd generation crosstreks, maybe he just didn't have a newer car on hand to demo the procedure.

 

I just did the CRC treatment today for my Forester. I last did it 9K miles ago. Tomorrow I will do the '19 Crosstrek. I did it last 18K miles ago. I was not going to do it again bc I plan on trading it in for the WRX as soon as I can get one. Decided though to do it anyway. It is quick and costs 15 bucks. But again effectiveness is unknown. CRC claims to remove 46% of deposits.

 

I try not watch videos usually it’s just to see what parts look like writing on parts and what not to do. Most shops use bg upper intake combustion cleaner it’s a three step process usually. I personally like to swap plugs after the tanker gas. Step on check air filter clean components maf maf cleaner if applicable. Step two take of air plenum or boot to throttle body. Clean throttle body completely with throttle body cleaner. Step 3 put back together and find a vacuum line or spray through the air intake. Spray upper intake and combustion cleaner not the sea foams lube. Why I suggested precleaning to first. You want velocity to cleaner that will eventually disperse into combustion chambers not all collect or dump in one cylinder. Also watch out for intake runners if applicable. Step 4 add fuel system cleaner and drive tank full of bg44k. Step 5 replace plugs and reset adaptive learning if applicable relearn all values or let idle and drive. You can relearn at any point tb needs new values. Boom done .