2016~2021 How to: Off the shelf intake valve cleaning in a can 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.


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)


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:


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.