Direct injection and residual oil issues

[concept]

I've been reading that many auto manufacturers' direct injection engines are allowing lots of oil to coat valves. That oil turns into hard carbon that can be tough to remove. Audi and VW engines have had a head start with DI and they are paying the price. Has anyone thought about this before buying your 3? I am intending to buy one, but will immediately throw in a catch can (oil/air separator) to see what it catches.
It would be nice if I could ask a Mazda development engineer, directly if this issue had been noticed. If so, what was the severity and what, if anything is being done about it?

 

[whiteline]

http://www.motoiq.com/MagazineArtic...l-introducing-mazdas-skyactiv-technology.aspx

To eliminate the problem of intake valve deposits that plague current direct gasoline injection engines, the engineers at Mazda determined that deposits are formed when intake valve temperatures fall below 400 degrees C. Measures were taken so that the intake valve would operate above this point to reduce deposit formation.

 

[Chibana]

I've also heard that using a full synthetic oil with a very low NOACK volatility can reduce that carbon buildup. A coworker of mine who is a bit of a gearhead and just purchased a car with a DI engine did some research. He's now an AMSOIL dealer just so that he can order AMSOIL oils at dealer prices for some of us at work who are interested. I have a box of 0W-20 AMSOIL full synthetic waiting for me at the office for my next oil change in my Mazda3.

http://www.1st-in-synthetics.com/what_is_the_noack_volatility_test.htm
http://www.amsoil.com/shop/by-produ...00-percent-synthetic-motor-oil/?code=ASMQT-EA

 

[concept]

Great find, whiteline! Notice that the word "reduce" is inserted in that quote. Since I design catch cans as a side hobby, I may still see what one can do in a 3.

I know for a fact that the new GM truck owners are seeing lots of oil on valve train components.

Chibana, I believe synthetic is less likely to form carbon, as I tend to start using synthetic after a few thousand miles (new vehicle). Since Mobil 1 is on sale every so often at Costco, that's what I get for every car in our family. I'm sure it's not as good as Amsoil, but you can't beat Costco's sales price.

 

[N0B0DY]

The Mazda 3 comes with synthetic oil from the factory. Mazda uses an oil with high moly content.

 

[hotcracker69]

good research. i have been wanting to get a new mazda as well, my protege has 220k and still running strong. proven engine and tranny.

not enough data to say for the new DI engine and transmission

 

[concept]

This why throwing a catch can on will reveal whether there is an issue with oil. Overall reliability of the 3, based upon previous generation changes, should be very good.

Sent from my Windows Phone 8X by HTC using Tapatalk

 

[mz3_driver]

http://www.motoiq.com/MagazineArtic...l-introducing-mazdas-skyactiv-technology.aspx

I see the words "eliminate" and "reduce", and they are not one and the same.

Carbon buildup will still be an issue on Mazda engines, as it will be on just about every DI engine (discounting hybrid DI/FI engines). What Mazda has done is keep the valve above temps of 400*, although this will still be an issue on cold starts and in the winter.

We'll see how long it lasts before requiring carbon cleaning. It will depend largely on driving style, oils used, etc... My mom's 2005 Audi A6 (with 3.2L V6 DI engine) has not had a carbon buildup yet, and the engine has 160K kms on it. It may likely require cleaning down the road (say at 180K, or 200K), but that's only if it's severe enough.

Mechanic checked with a camera, and said it's looking pretty good still.

 

[concept]

I'm actually surprised, as other Audi owners are seeing lots of oil. Perhaps Audi designed an improved oil trap for newer models?
A catch can can't hurt. I have a glass version that uses a dual-stage filter, mounted in the Corvette. This will be sold with that car, so another one will go into the 3, as long as there's a good place for it.

 

[DougNuts]

Mazda also says that when running in Atkinson cycle, the engine will clean the valves by pushing a little atomized fuel into the intake tract before sucking it back in.

 

[concept]

...good to know.
As an aside, my 2014 3S GT Sedan with 300 miles on the odometer is averaging 32.8 MPH with daily 20 minutes of heavy stop & go traffic + 30 minutes of 70 MPH highway driving.