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GDI intake valve cleaning

17969 Views 13 Replies 6 Participants Last post by  arathol
Since our engines are the Gas Direct Injection type has anyone done a cleaning of the intake valves? I'm in the process of doing it now using CRC GDI iVD Intake Valve and Turbo Cleaner. I'm at the 1-hour heat soak point right now so I though I'd take a break to make this post. If it all works well then I'll post my procedure and it is pretty simple and straight forward so fingers crossed. Wish me luck.
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Is there any particular reason you are doing this? Was there an issue or just because?
I was actually just wondering if there was any actual evidence of build up such as bore scope pics or any sort of symptoms such as rough idle, power loss etc. There has been much discussion on the merits of Mazdas approach to preventing buildup. It seems to work for some, not so much for others. It would be interesting to see what sort of build up there was and the results of the cleaning process.
Mazdas idea is to design the coolant passages in the head in such a way that the intake valves stay real hot, above 400°C, the point where they say deposits aren't supposed to form. There are a bunch of SkyActiv cars now with a lot of miles on them and reports of problems don't seem to be too common, not like BMW or Hyundai anyhow where every car seems to have issues.
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There is a ton of info on this if you actually cared to look. Certain cars have certain issues that are well known among owners groups, this is reflected on their respective owners forums. BMWs are notorious for this problem, as are VWs and Hyundais and its been discussed to death. There seems to be on the other hand very few complaints from actual Mazda owners on this even after 6 years of SA production. In fact its just the opposite for the most part with many cars at 100k miles or more and no issues. The few pictures I have seen do show some buildup but not enough to be relevant. Some (most) of it can be shown to be to related to driving the car short distances with insufficient time to get the temps up to where the carbon shedding can occur.
There is a particular vendor that claims to show how much oil gets through the PCV system using a catch can, oil that has been said to cause deposits on the intake valves. However, those pictures when closely examined show that the captured "oil" is mostly moisture with a tiny bit of oil on top....
So, just because you read something on the internet doesn't mean its real either.

As to any cleaning using water to dislodge the carbon, I would consider asking Mazda first. If the intake valves are indeed kept at 700°F or more when the engine is at proper operating temperature, hitting them with water might cause some stress issues. Bending, twisting and fracturing valves could get expensive fast.
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I just found out about this issue and was thinking of spraying my intake with the CRC GDI Intake Cleaner every 10-15000 miles. I do have an inspection camera so I can try looking and/or taking a picture first.

One thing I heard suggested was a catch can. I ordered one of these Chinesium/Al units off Amazon for 25 dollars. Quality really wasn't bad although all the threads on it sound kinda "scrapyard" and the dipstick is lacking an o-ring.

Question is... where to mount it? I can only find three halfway decent spots, none of which I like.

1) Against the plastic lip of the rain tray in the dead center. It gives very easy access, but it means you are mounting to plastic and it's directly over the exhaust.

2) Right shock tower. This seems like a good place. But do I want to drill through the shock tower and how exactly would I attach it. There's a little vertical bracket with two holes that's screwed into it. It's possible I could remove the bracket, drill through shock tower and then just use screws from inside the shock tower into the threaded holes used to hold the bracket.

3) Just behind the left headlight. Probably the ideal location but I can't figure out how to actually attach it. Pretty much everything there is plastic and it's cramped.

What issue? There is no real issue here and the catch can is a solution to a problem that doesn't really exist.
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