GDI Carbon Buildup Maintenance

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Guest201874

This is my first GDI engine. I am now aware of the intake valve carbon issue.

I have used on my other cars Lucas fuel treatment every 2500 miles and Techron every 5000 miles. I understand this will help but the back side of the intake valves may not get cleaned.

I am wondering if using Seafoam and or CRC cleaner thru the throttle body at around 50000 miles is a good move or is a professional cleaning needed?

Any other suggestions?
 
Running the cleaner as suggested will clean your injectors but cannot help with any buildup behind the intake valves. That is where gas used to enter the combustion chamber.

Run a good d1G2 SN+ oil and top tier fuel. Keep short trips as minimal as possible. Get your car on the highway. These engines want to run.
 
This is my first GDI engine. I am now aware of the intake valve carbon issue.

I have used on my other cars Lucas fuel treatment every 2500 miles and Techron every 5000 miles. I understand this will help but the back side of the intake valves may not get cleaned.

I am wondering if using Seafoam and or CRC cleaner thru the throttle body at around 50000 miles is a good move or is a professional cleaning needed?

Any other suggestions?

I have 95K miles on my CX5. I have had zero issues, nor have I done anything special that I haven't done for my other cars, which is nothing but change the oil at 5- 7500 miles using the best sensibly product I can (in this case, Pennzoil Platinum, Gen2 Dexos 1 rated). I changed spark plugs at 75K-ish miles, and that didn't do anything and the plugs were just fine, but this forum talked me into it...meh.
 
Intake vavle getting gunked up is also dependent on what is the car used for. It is a preventive maintenance that I would not worry till 100K miles. I would however, not use the CRC cleaners that are advertised for cleaning the valves as the carbon buildup can damage parts of the engine or the Cat convertors. A better way is old fashioned - clean it by hand.
I would worry more about transmission drain and fill instead of intake valves.
 
I agree, I would not spray carbon cleaners in there. Other users shared their experiences. Codes popping up, engine going into limp mode, loud pinging. No thank you!

If you really feel inclined take the intake manifold off and clean manually with a carbon cleaner, brushes and machinist scribe. But if you are not experiencing a drop in mileage or performance issues, why bother?
 
You can use CRC GDI intake cleaner through a vacuum line (or the fresh air hose inlet past the maf). I've done it before (twice) no adverse side effect.. but I drive my engine high rpms normally and have an oil catch can so probably won't have as much build up
 
Great video, thanks for sharing! Science of it jives with the Mazda claim that by engineering the engine to have temps there at 400, carbon deposits aren*t an issue.
 
Great video, thanks for sharing! Science of it jives with the Mazda claim that by engineering the engine to have temps there at 400, carbon deposits aren*t an issue.

It still happens. Doesn't seem like it's and critical issue but it means less efficiency. Drag on your valve train gonna affect your mid/top end more the worse it gets. Easier to maintain than pull the IM and scrub.
 
Intake vavle getting gunked up is also dependent on what is the car used for. It is a preventive maintenance that I would not worry till 100K miles. I would however, not use the CRC cleaners that are advertised for cleaning the valves as the carbon buildup can damage parts of the engine or the Cat convertors. A better way is old fashioned - clean it by hand.
I would worry more about transmission drain and fill instead of intake valves.

It appears Mazda has made it where we can actually clean by hand....which is much more effective anyways. Now I just need extra time at hand to do the project.
 
It appears Mazda has made it where we can actually clean by hand....which is much more effective anyways. Now I just need extra time at hand to do the project.

How hard is that to do, and is there a specific mileage that would be good to tackle it? I'm approaching 75k currently.
 
How hard is that to do, and is there a specific mileage that would be good to tackle it? I'm approaching 75k currently.

I'm confident we can do this...the only question which I posed and seeking answers for is how to rotate the engine. Since two valves are closed (and ready for cleaning) and two are open. We need to rotate the engine so that the other two are closed.

Otherwise I may just clean 2 valves now...get lucky and next time I access it the other two are closed lol.

You're basically scrapping/sucking out gunk and fluid from the inside of a metal squared cylinder, connected to another rounded cylinder, and from a small metal triangular shaped object found inside said rounded cylinder. x4.
 
https://youtu.be/mhG1ZBqMnKA

Looks like everything you would need to know to get the job done. This dude takes the passenger side wheel off and turns the engine by hand with a breaker bar/ratchet to open and close the valves as necessary. Says to use a 21mm socket to turn the crankshaft pulley.

I*m probably starting to sound like a broken record, but it seems like an awful lot of work unless you are experiencing an actual loss of performance or efficiency. I wont attempt until I think it*s necessary.
 
https://youtu.be/mhG1ZBqMnKA

Looks like everything you would need to know to get the job done. This dude takes the passenger side wheel off and turns the engine by hand with a breaker bar/ratchet to open and close the valves as necessary. Says to use a 21mm socket to turn the crankshaft pulley.

I*m probably starting to sound like a broken record, but it seems like an awful lot of work unless you are experiencing an actual loss of performance or efficiency. I wont attempt until I think it*s necessary.

I get you. Its more of a curiosity thing for me. Plus I love performing service work knowing it costs hundreds for a shop/dealership to do it. All that said....I expect to remove tons of sludge upon which photos would be my trophy!!! :)

Otherwise from a performance aspect only...would not touch unless I need to.
 
It would be most rewarding lol! I get the biggest sense of accomplishment of doing simple drain and fills on my vehicle transmissions for than same reason.

What worries me is using an intake cleaner on an engine in that shape and blowing all that crap through. Seems absolutely fine if you know your valves aren*t that bad, but holy cow! Could you imagine all that crap in that guys intake getting blown through the rest of the system?
 
I think the key is regular maintenance with fuel system cleaners and maybe a Seafoam treatment every 25000 miles. A clean PCV and the right oil will also help.

No doubt some of the horrific photos of valves are from those who never cleaned and used cheap gas to boot.
 
Call me old fashioned but I'm of the opinion of"if it ain't broke,don't fix it".If it runs good and gets good fuel mileage I see no need to introduce various cleaners or tear into the engine to manually clean carbon.It's easy to get caught up in the "over maintain it " mindset without realizing it.There's alot of "miracle products" on the auto parts store shelves just waiting to correct your car's possible or perceived problem.
Maybe my thoughts will change in time as the car gets more miles and age on it.Just my .02. Jmaz
 
You can use CRC GDI intake cleaner through a vacuum line (or the fresh air hose inlet past the maf). I've done it before (twice) no adverse side effect.. but I drive my engine high rpms normally and have an oil catch can so probably won't have as much build up

I saw a video on YouTube of a mechanic spraying CRC GDI unto a really carbonated BMW turbo engine directly unto the valves. I saw the product started to bubble up and dissolve the carbon. It must be really effective stuff!!! I think I'll do it before each oil change. I heard nothing but good reviews from knowledge people. The only negative reviews involved inproper application. You have to spray it AFTER the MAF sensor.

That said where is the said vacuum line?
 
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