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I am at 25k on my car now (2014) and I just realized (really late, my fault) that skyactiv is a direct injection engine. So what are you guys doing to combat the carbon-on-the-valves issue? I read that every 20-30k they need to be cleaned. But I'm not so sure about the chemicals on the marker (snake oil?) that you just spray into the intake. Is it better to take it to the dealer?
 

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There's no specified interval to clean carbon from the valves. That sounds like something somebody is trying to sell you so you buy their cleaning products. My 2014 Touring is about to hit 112,000 miles and the only "extra" thing I'll do is empty a can of $5 Chevron Techron into the gas tank every oil change or so.
 

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I've got ~130,000 on my '15 and I've done exactly zero with the valves. If the engine doesn't have issues (mine doesn't) then do the scheduled maintenance and drive the car.
 

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Unfortunately, no fuel system cleaner is going to do anything for intake carbon build-up on a typical DI engine, since fuel is injected directly into the combustion chamber.

That being said...the word on the street re. intake carbon deposits on Skyactiv DI engines was that Mazda engineers had those under control via some sort of thermal magic performed during the normal drive cycle...? Don't ask me to explain.

Typically, you'll need to start worrying about intake carbon at 60-80k miles. Tickerguy and others have way in excess of that on their cars and zero issues. It would appear the rumor is probably correct.

I'm employing the "grandfather rule" with mine..."if it ain't f***ing-up, don't f*** with it!"
 
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Though Tecron does not clean the back of the intake valves it does 'something good' and every time I put it I notice the car run extra smooth. If definitely cleans something, so I do the Tecron regimen once every 3 months. Considering that Ticker, Byakuya and others are well north of 125K miles with zero issues I do believe Mazda has addressed the carbon buildup problem in their Skyactive engine design.
 

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I'm guessing with the OP driving a lot less miles per year than tickerguy & dasrider it would be more prone to carbon buildup.
 

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Though Tecron does not clean the back of the intake valves it does 'something good' and every time I put it I notice the car run extra smooth. If definitely cleans something, so I do the Tecron regimen once every 3 months.
Tecron has been proven to be one of the few fuel additive products you can buy that actually does something.
 

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I do the following:
I run top tier fuels most of the time
I use a good fuel injector cleaner every 5k miles (redline or techron)
I run the lowest NOACK 0W-20 Synthetic I can find (mobil 1 EP works for me)
I drive the car 50+ miles a day - it gets fully warmed up and is driven at highway speeds.

I have 72,000 on it now with zero engine trouble, hesitation, or loss of power. Tickerguy has more miles than me, and I've spoken to a few over 150k with zero engine trouble. This is a non-issue with these motors. Sure, there might be some carbon on the valves, but they don't continue to build carbon and create engine faults over time.
 

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There's no specified interval to clean carbon from the valves. That sounds like something somebody is trying to sell you so you buy their cleaning products. My 2014 Touring is about to hit 112,000 miles and the only "extra" thing I'll do is empty a can of $5 Chevron Techron into the gas tank every oil change or so.
I've got ~130,000 on my '15 and I've done exactly zero with the valves. If the engine doesn't have issues (mine doesn't) then do the scheduled maintenance and drive the car.
I'm with these two. At around 125k miles and haven't thought about cleaning buildup even once.

That being said: proper preventative maintenance is never a bad idea, so take into consideration what some of the other members are saying too :)
 

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I drive the car 50+ miles a day - it gets fully warmed up and is driven at highway speeds.

I think this part is key to really long life in an engine along with regular maintenance. Obviously, not everyone can do 50 miles everyday though. I've got a 1994 Ranger with 411,000 miles on it with the original engine. My dad bought it new and commuted 80+ miles a day for several years, almost all highway miles.

Same with a 1996 Integra my wife drove for a long time. Longish highway commute with little stop n' go. I sold it last year with 389,000 miles. The 2008 Scion she drives now has 220,000 miles, although her commute has changed drastically recently due to a <10 mile, all city commute. I expect the motor to explode at any minute now... :wink2:
 

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I'm at 97k and the only maintenance I've done is oil changes, spark plugs (which made no difference, btw), manual transmission fluid changes, filter changes, and I swapped out my coolant once. Everything else has been ticking like clockwork. Come to think of it, I really need to flush my brake lines. I did a suck'n'fill via the turkey baster method once at like 50k miles but that's it!
 

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That being said...the word on the street re. intake carbon deposits on Skyactiv DI engines was that Mazda engineers had those under control via some sort of thermal magic performed during the normal drive cycle...? Don't ask me to explain.
I found this link talking about that.
13:1 Compression and 40 mpg on 87 Octane fuel? Introducing Mazda?s Skyactiv Technology

This is a timely thread for me. For some reason videos started showing up in my Youtube feed about carbon buildup on GDI engines. I have 75K miles on my '15 Mazda6 and it's running great but I started to wonder if others have had any problems with this.
 

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I found this link talking about that.
13:1 Compression and 40 mpg on 87 Octane fuel? Introducing Mazda?s Skyactiv Technology

This is a timely thread for me. For some reason videos started showing up in my Youtube feed about carbon buildup on GDI engines. I have 75K miles on my '15 Mazda6 and it's running great but I started to wonder if others have had any problems with this.
It’s timely because a lot of GDI engines are getting up in mileage and starting to show deposit problems. I know Toyota and Subaru are going to hybrid DI/PI fuel systems to combat deposits. VW has also, but not on their North American products...which is odd and unfortunate, since their TSI motors are famous for deposit formation.
:frown2:
 

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It’s timely because a lot of GDI engines are getting up in mileage and starting to show deposit problems. I know Toyota and Subaru are going to hybrid DI/PI fuel systems to combat deposits. VW has also, but not on their North American products...which is odd and unfortunate, since their TSI motors are famous for deposit formation.
:frown2:

Ford has both DI/PFI with the 2018 5.0,



https://www.roadandtrack.com/new-cars/car-technology/a20717339/2018-ford-mustang-gt-v8-details/
 

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I've done exactly nothing about it because nothing is required on these engines, in my experience.

YMMV of course but I have zero indication of trouble and more than 130k miles on the clock at this point. No decrease in mileage, performance or other misbehavior. None.

Mazda claims they took care of it through engineering by keeping temperatures in a range where the fouling doesn't occur. I don't know if they're right or not, but until and unless I have a reason to pull the intake and look I'm not going to.

Incidentally doing that isn't all that hard on these engines, should you choose to -- but why do something without any need to do so?

Now if you want to discuss engines where that IS a very real issue that I've had to deal with may I introduce you to the '03 Jetta TDI in my garage.....
 

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If it should ever be necessary to perform a crushed walnut shell intake valve/port blast you simply could not have an easier engine to do it on - what with a front-orientated intake set up, no turbo plumbing, etc. I agree with Tickerguy - do nothing unless or until it is nec... This ease of access, in part, informed my choice of this car. Compared to the Accord.... opposite on both aspects...
 

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If it should ever be necessary to perform a crushed walnut shell intake valve/port blast you simply could not have an easier engine to do it on - what with a front-orientated intake set up, no turbo plumbing, etc. I agree with Tickerguy - do nothing unless or until it is nec... This ease of access, in part, informed my choice of this car. Compared to the Accord.... opposite on both aspects...
Lol! Isn’t it funny how the easier it is to get to a component or system, the less likely it is to break...and visa-versa? :|
 
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