Guide: Off the shelf intake valve cleaning in a can for 2.5T

Hello everybody!

The potential to have dirty intake valves is present in most Direct Injection (D.I.) vehicles. Add to that a Turbo and you get a Turbo Gasoline Direct Injection (TGDI) engine, that is even more prone to dirty intake valves due to the high heat of the turbo. It's important to use an oil that meets the American Petroleum Institutes (API) SN+ or higher specifications, especially in our Mazdas with a turbo. The newest Spec (2020) is the SP rating along with the GF-6 rating from the International Lubricant Specification Advisory Committee (ILSAC). You can check the API donut on a manufacturers oil jug. Idemitsu 5w-30 full synthetic meets the SP & GF-6 rating currently, the ZEPRO varient currently does not, curiously it only meets the base SN rating, not the more advanced SN+, perhaps it does meet them, but Idemitsu did not submit that variety through the testing knowing SP ratings will soon supercede the SN+. Hard to tell, but I hope the ZEPRO can meet the SP rating here soon.

Off the shelf valve cleaning: This is a simple technique that is minimally invasive. Next year I plan on going down the route and doing a walnut shell blasting of the intake valves themselves and I will post that "how to" when that time comes.

I used a kit made by Berrymans, called "Intake Valve and Combustion chamber cleaner" This product is a High Energy Solvent Technology (H.E.S.T.) product which I like a little more than other off the shelf products for valve cleaning.

This how to is specifically for the 2.5T skyactive found in the CX-9, I assume it would be similar for a CX-5 or Mazda 6 with this engine. I cannot guarantee that.

Note: Do not use the yellow curve straw method by removing the intercooler charge pipe, the vehicle WILL NOT RUN/IDLE and will stall, making it impossible to administer the product using this method.

20200731_163718_HDR.jpg


Items needed from the kit:
  1. Larger of the 2 braided hoses
  2. The 4 (4 cylinder or smaller engines) or 6 (V6+ sized engines) sided reduction fitting
  3. The blue stepped fitting
  4. Rag from your house
Step 1: Open your hood
Step 2: Remove the engine cover
Step 3: Locate the throttle body toward the front of your engine bay see picture below: (Don't mind my intercooler pipe being disconnected I was experimenting with ways to use this kit)

20200731_163744_HDR.jpg


Step 4: Above the throttle body is the plastic intake manifold.
A. The rubber Vacuum hose (#19 on the picture below) right above the throttle body on the lowest part of the intake manifold is the vacuum hose we want to remove. Not hose #16! Which is connected to the metal throttle body housing. That is a liquid filled coolant line! This hose has a metal clip you need to squeeze with a pair of pliers and move it farther down the hose to be able to remove the hose from the manifold.

Screenshot 2020-07-31 at 4.25.32 PM.png


Step 5: Once removed you need the larger of the 2 braided hoses in the kit. Slip this over the plastic nipple on the intake manifold (If you have trouble getting this to fit, you can heat up the hose with hot or boiling water).

Step 6: Use either the 4 or 6 sided reduction fitting from the kit and attach it to the can side of the long clear hose. I had to use the 6 sided fitting because the 4 sided fitting wasn't working, I'm not sure why.)

Step 7: Attach the blue stepped fitting hose side to the output side of the reduction fitting.

Step 8: Attach the blue stepped fitting tightly into the large braided hose already attached to the intake manifold. Everything should look like this below:

20200731_164628_HDR.jpg


At this point everything should be ready to go. Do one look through to make sure everything is snug and there are no kinks in any of the tubing. Also place the can on a rag or wrapped in a rag, my can leaked (details at the end).

Step 9: Start the vehicle and push the button on the can down to start the flow of cleaning agent. You can stop the flow by depressing the small button on the back of the plastic cap.

Step 10: Once the can is empty stop the vehicle and unplug the large diameter braided hose and reattach the vacuum line, not forgetting the re-fit the metal pinch clamp.

Step 11: Re-install the plastic engine cover.

Step 12: Wait 30 minutes, after 30 minutes drive the vehicle for at least 10 minutes as directed by the product instruction.

This method creates smoke like a seafoam style treatment does, however contrary to internet lore, the smoke is not all your carbon being burnt off, sorry.
My observations:
  • Do not remove the intercooler hose as I mentioned at the top in bold, if you get this method to work good job please share how you got your vehicle to run without keeping a foot on the gas pedal.
  • The smoke it makes absolutely stinks, it's worse than any seafoam treatment I did in my youth to my older vehicles.
  • I took it for 3 drives, the third drive I took it on a short freeway blast and observed the best MPGs I've seen with this car to date. I'm skeptical of stuff like this really working but I think it was worth a shot.
  • I think next year when I do a walnut blasting I'll use this kit first to see if it actually removes any carbon before taking the manifold off.
  • My can started to leak at the very end, and I ended up with some on my hand. I got firsthand experience with how aggressive the chemicals in this can are, it started to burn my hands and even a day later my hand is super dry from the chemicals. Because of this I recommend you keep the can on some type of rag so that if yours leaks it doesn't ruin any paint. I got lucky as I had a rag present at the time and none touched my paint.
  • I kept the braided hose and the blue stepped bit for future use with other types of intake cleaner. I believe you should be able to use a type with a red straw and insert it into the tube and be able to inject it into the vacuum line this way.
I hope this works for anyone who attempts to do this in the future. Proceed at your own risk and use common sense when playing with chemicals meant to eat away carbon deposits.
 
Last edited:
:
2018 CX-9 Signature
Thank you for this thorough write up! I've been looking for a better inlet other than the charge pipe after the air filter. It's such a long route going through the turbo then all the piping and through the intercooler till the valve. This inlet you mentioned is much more direct to the valves. (y)
 
Thank you for the write up!! Do you mind explaining what happened with the can and where it leaked?
The top part of the can, where the black push tab meets the small straw type thing on the top of the can. Hard to explain, but that mating surface between the two split. So I had to manually cycle the flow on and off to get it from overflowing and foaming from the top of the can. The chemicals completely stripped the ink from the cans wrapping it was so strong.
 
Have you inspected your valves and/or intake manifold with a borescope?
I was going to look at my Piston crown and valve recess's with my borescope while I was doing my spark plugs but I forgot. I might pull them out in the summer when I do my walnut basting. I haven't given it much thought, but the only way I can think of looking at the intake runners or intake valves would be getting my borescope and going up from the throttle body. I might try that this summer before I take the whole thing apart, it might save me some time if the valves are in fact clean.

Do you have any experience viewing the valves this way?
 
I was going to look at my Piston crown and valve recess's with my borescope while I was doing my spark plugs but I forgot. I might pull them out in the summer when I do my walnut basting. I haven't given it much thought, but the only way I can think of looking at the intake runners or intake valves would be getting my borescope and going up from the throttle body. I might try that this summer before I take the whole thing apart, it might save me some time if the valves are in fact clean.

Do you have any experience viewing the valves this way?

Why would you bother to clean with chemicals and/or walnuts if you have not first inspected the valves? Without evidence of build-up, or a 'before & after' shot, this post is really not terribly useful.
 
Why would you bother to clean with chemicals and/or walnuts if you have not first inspected the valves? Without evidence of build-up, or a 'before & after' shot, this post is really not terribly useful.
Have you seen the process to inspect the valves? I bet you probably have not; I have and in the meantime this was a simple way to potentially clean the valves, especially given the track record direct injection engines have currently with the abundance of build up. And given that Mazdas DO have a dirty DI track record, so much so that Corksport made a silicone intake valves cleaning attachment, makes this thread a little more useful than you might be giving it credit for.

I think it's kind of funny you say this post is not terribly useful, given the track record of DI engines these days. This post is a thorough guide on a simple and cheap preventative measure. It's not being passed off as a fix, or a complete valve cleaning, the kit only costs $20.

I ask you this, do you test your air filters CFM before you replace them, or get every oil change analyzed by an oil lab to know how much life your oil had left? Of course not because it would be expensive to do and be downright silly especially given how cheap the cost of a new filter or oil is. But we change these things early to do preventative maintenance as a means to prevent failures. You clean your dryer vents before a fire starts, and change your furnace filter regularly to keep your furnace blower from burning up, I hope.

We do these things to keep our investments running in peak shape, while not throwing money out the door.

I do plan on taking my intake manifold off this coming summer, and I hope the valves are clean. But in the meantime before I spend 2 or 3 hours to: drain the coolant, remove the EGR cooler, remove the EGR pipe, remove the MAP and IAT sensors, disconnect and remove the water hoses, disconnect and remove the high pressure fuel sensors, disconnect and remove the throttle body and water lines that run into that, to finally get to the intake manifold just for a valve inspection to see if a $20 kit would be beneficial or not?

2-3 hours of disassembly/reassembly + coolant costs vs $20 and 10 minutes of time to use this chemical kit.

That borescope you mention? How much does that cost and can you guarantee you can make it far enough into the intake system to see the valves?

Looks to me like the cost benefit analysis doesn't stand on your side of the argument.

Yeah doesn't make this $20 intake valve cleaning in a can seem so "not terribly useful" anymore does it?
 

speed3chris1

2021 Signature CX-9
Just for the record Direct Injection will always leave carbon deposits on the intake valves because no fuel is running over the valve. Some cars are worse than others. You would be shocked at the deposits that were on the valves of my 2008 Speed3 after 35-40 thousand miles. I use the Berryman's every time I change the oil.
 
Have you seen the process to inspect the valves? I bet you probably have not; I have and in the meantime this was a simple way to potentially clean the valves, especially given the track record direct injection engines have currently with the abundance of build up. And given that Mazdas DO have a dirty DI track record, so much so that Corksport made a silicone intake valves cleaning attachment, makes this thread a little more useful than you might be giving it credit for.

I think it's kind of funny you say this post is not terribly useful, given the track record of DI engines these days. This post is a thorough guide on a simple and cheap preventative measure. It's not being passed off as a fix, or a complete valve cleaning, the kit only costs $20.

I ask you this, do you test your air filters CFM before you replace them, or get every oil change analyzed by an oil lab to know how much life your oil had left? Of course not because it would be expensive to do and be downright silly especially given how cheap the cost of a new filter or oil is. But we change these things early to do preventative maintenance as a means to prevent failures. You clean your dryer vents before a fire starts, and change your furnace filter regularly to keep your furnace blower from burning up, I hope.

We do these things to keep our investments running in peak shape, while not throwing money out the door.

I do plan on taking my intake manifold off this coming summer, and I hope the valves are clean. But in the meantime before I spend 2 or 3 hours to: drain the coolant, remove the EGR cooler, remove the EGR pipe, remove the MAP and IAT sensors, disconnect and remove the water hoses, disconnect and remove the high pressure fuel sensors, disconnect and remove the throttle body and water lines that run into that, to finally get to the intake manifold just for a valve inspection to see if a $20 kit would be beneficial or not?

2-3 hours of disassembly/reassembly + coolant costs vs $20 and 10 minutes of time to use this chemical kit.

That borescope you mention? How much does that cost and can you guarantee you can make it far enough into the intake system to see the valves?

Looks to me like the cost benefit analysis doesn't stand on your side of the argument.

Yeah doesn't make this $20 intake valve cleaning in a can seem so "not terribly useful" anymore does it?

Apologies if I offended you. Not my intention.

I have owned several GDI powered cars (mostly BMW and Audi/VW); to date, I've not had carbon issues likely due to my driving style (longer distance w/ plenty of RPMS) and use of good quality fuel and lubricants.

I am not that concerned about carbon issues in the Mazda--it's not (yet) widely reported like early BMW N54s or VW/Audi EA888s.

Mazda claims to leverage the EGR to cool the intake rather than run the engine rich; likewise, Mazda claims to run the intake warm enough to burn off carbon from intake valves (though this would not prevent carbon in the intake manifold via a less-than-perfect PVC system).

The Mazda 2.5T is a relatively young engine. I'm curious to see how it's going to age. Hence my question whether or not you've inspected the intake manifold or valves via a borescope.

If there was evidence of carbon, I would have found it useful to understand if it was coming from the PCV/intake or running down the valve seals/stems (or perhaps a bit of both).

Even if I had evidence of carbon, I would be tentative about running a product like B12 through the intake. I am not saying you should not, but here's why I would not:
  • The chemical cleaning products are not that effective at cleaning carbon. I found this video from DAP pretty interesting:
    )
  • I'd be concerned about fouling plugs and sensors
  • Risk of cleaning/de-greasing components that are designed to remain lubricated (e.g. cylinder walls)
As for the borescope question, I've only peeked into my VW GTI's EA888: I can peak into the combustion chamber via the spark plug hole; the intake manifold + intake valves via the air intake (downstream of the air cleaner).
 
Last edited: