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'10 3.0 AWD Sedan
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I've read recently that now that DI engines have been around for a little bit they are showing signs of carbon deposits forming on the intake vales. This is because gas isn't passing thru to "wash" the valves. I read separately that the issue is
exasperated on smaller displacement engines and by a car used for a lot of short trips. I have a '10 3.0 AWD that has 11K miles after two years of service so my car fits the bill. Has anyone else heard this and is there anything that can be done to safe guard against it? I am currently running a bottle of Techron thru it but since the fuel doesn't pass the intake valve I guess it won't help at all.
 

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2010 CTS Premium AWD 3.6 DI (Sold)
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I take mine out and nail it every month or two. This is also referred to as an Italian Tune-up. You will be surprised what comes out the exhaust.
 

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'14 CTS-V LongRoof; '16 ATS-V Sedan,' 04 Trailblazer 4x4; '10 CTS LongRoof gone but never forgotten
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droptopron, you are right that Techron won't do anything. Many of us are installing Catch Cans to help trap oil and keep it from fouling the valves. Definitely try blankster suggestion of an Italian tune-up. Whether or not it works it is a carload of fun! Other than a seafoam bath that some have suggested the only other thing to do is a head job. (Did I say that?)
 

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http://www.cadillacforums.com/forums/cadillac-cts-first-generation-forum-2003/269172-rx-oil-separating-catchcan-ly7.html

Here is a picture of a LY7 w/app 140k miles on it and the chamber is clean due to top tier fuels being used:


And 16K on the DI version (2008-2013):



And a LLT that a RX Catchcan system was installed at 3k miles, currently 17k miles:


Notice the deposits already formed at 3k miles but have not added any since the RX system was installed and how you can see from the color no oil ingestion entering as the RX system stops all intake charge ingestion.

www.RevXtreme.com
941=721-1826
 

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2016 XTS Premium
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Only suggest GM recommended Fuel System Treatment Plus and I know others say no or use other stuff but it gives me piece of mind. See TSB 05-00-89-078C, dated April 12 for Coupe.
 

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'14 CTS-V LongRoof; '16 ATS-V Sedan,' 04 Trailblazer 4x4; '10 CTS LongRoof gone but never forgotten
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But you are wasting your money. With DI, gasoline does not flow over the valves, it is Injected Directly into the cylinders. You could put darn near anything in your gas and nothing will clean your valves. Nothing.
 
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Only suggest GM recommended Fuel System Treatment Plus and I know others say no or use other stuff but it gives me piece of mind. See TSB 05-00-89-078C, dated April 12 for Coupe.
Just so you know the Gm Fuel treatment plus Is just relabeled Chevron Techron Fuel Concentrate Plus at $10-13 more a bottle lol
BMW uses it too..






 

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'14 CTS-V LongRoof; '16 ATS-V Sedan,' 04 Trailblazer 4x4; '10 CTS LongRoof gone but never forgotten
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Oh, c'mon, CTSCHICK, you know that is merely coincidental!:D
 

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2008 CTS 3.6L DI RWD, GMPP new engine 11/2013
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Yeah, forget about cleaning the valves. Instead worry about the fuel gauge sending unit located inside the gas tank.

"The PLUS portion of GM Fuel System Treatment is the addition of a "filmer" additive that, when used regularly, can protect fuel sending units from the corrosive effects of sulfur contaminants found in some of today's gasoline.

Sulfur contamination may disrupt electrical continuity of fuel sending units and lead to erratic or false fuel gauge readings..."

:lildevil:

 

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'14 CTS-V LongRoof; '16 ATS-V Sedan,' 04 Trailblazer 4x4; '10 CTS LongRoof gone but never forgotten
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From the Techron website:

Techron Concentrate Plus

Whether protecting your new valuable investment, restoring your used car to its original performance, or simply helping keep your engine as clean as it can be, Techron Concentrate Plus delivers a number of unsurpassed benefits and one unique benefit - the ability to eliminate faulty fuel gauge readings.

Performance
Benefits
Science

Techron Concentrate Plus bottle
Capabilities of Techron Concentrate Plus
Cleans carburetors Yes
Cleans fuel injectors Yes
Cleans intake valves and ports Yes
Cleans combustion chambers Yes
Restores lost power and performance Yes
Lowers emissions Yes
Relieves cold startup problems Yes
Reduces deposit-related engine knocking and pinging Yes
Cleans sulfur deposits from gas gauge sensors Yes
Protects against fuel system sulfur deposits Yes
Protects gas gauge sensors from malfunctioning Yes
Contains PEA chemistry Yes
 
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Oh, c'mon, CTSCHICK, you know that is merely coincidental!:D
Haha yeh just saying I would hate to see some one pay $20-23 for a bottle of it when you can usually get them 2 for $10-12 at auto stores occasionally or $10 for the 20 ounce bottle since 1 ounce per gallon of the size of tank is needed..
 

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But this does NOTHING for a direct injection engine. Fuel must pass the intake valve for any additive to help keep coking/deposits.....and on a DI engine the fuel is injected in the final 20-30% of the compression stroke and never touches the valves. ONLY a good functioning oil separating catchcan can prevent this period.
 
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But this does NOTHING for a direct injection engine. Fuel must pass the intake valve for any additive to help keep coking/deposits.....and on a DI engine the fuel is injected in the final 20-30% of the compression stroke and never touches the valves. ONLY a good functioning oil separating catchcan can prevent this period.
I know that my 3.6 is my 2nd GM DI Engine a catch can has been a way of life for me

I was just mentioning it due to some one already mentioning the Gm fuel treatment
 

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But this does NOTHING for a direct injection engine. Fuel must pass the intake valve for any additive to help keep coking/deposits.....and on a DI engine the fuel is injected in the final 20-30% of the compression stroke and never touches the valves. ONLY a good functioning oil separating catchcan can prevent this period.
Nobody disagrees with you.
 

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Most that are active on the forums understand it, but most dealer service centers are still selling the additives to the customers telling them it will prevent this when it doesent. Now a non DI motor top tier fuels and or additives do a great job of helpping. :thumbsup:
 

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2009 CTS 3.6DI FE3 MN6
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Are the catch cans designed to catch excessive amounts or all of the returning oil?

I am thinking that having no oil or fuel laden air passing through the valves could cause issues over time. Could that be why the engine is allowed to circulate so much oil from the factory?
 

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The oil were talking about is oil that does not recirculate, but is ingested along with the crankcase combustion byproducts that do not do harm or cause the coking. The catchcan (only 3-4 on the market actually catch most of the oil, only one cathces ALL the noticeable oil) separates and traps the oil from these vapors and is then discarded properly with any waste oil. If you re-introduced this oil back into the crankcase with the concentration of damaging compounds you would drastically shorten your engines life.
 

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2009 CTS 3.6DI FE3 MN6
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Perhaps circulate was the wrong choice of word, I understand where the oil is coming from and that it should not go back to the crankcase. My concern is that without fuel from intake injection or the oil from crankcase vapor there could be potential for long term damage to the valves. Would the valve seats be affected without lubrication? Does the vapor in the intake air aid with cooling the valves? Intake injection certainly keeps the valves clean but the waste oil would still come into contact with the valves and could be beneficial.

I burn about 3/4s of a quart every 4 to 5 thousand miles on my CTS. I did make sure to vary the RPMs greatly within the first few hundred miles and today I use the whole RPM range every chance I get. For my driving style I think the oil burned is acceptable and I make sure to keep it at the proper level.
 

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No oil should ever be in the intake air charge, It is an unintended part of the closed PCV systems of today and now that most all motors are, or will be DI by 2015 the problems have compounded:




As you can see, this is caused by the oil ingestion and the buildup not only reduces the volumetric efficiency of the intake port and valve design causing loss of power & fuel economy, it wears the valve guides out prematurely adding to oil consumption issues as well.
NO oil should ever be ingested into the intake air charge.
 
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