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Suggestion on Piston/Ring cleaning for abnormal oil consumption?


hawaiianstyln

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My previous 04 Malibu had an oil consumption and dealers just told me it was normal.  3 boats later after that, I have an 08 with a 340 Monsoon and have an oil consumption problem again (boat was bought used).  Boat runs amazing, I just have to add a quart about every month with 550 hours.  I don't surf and I only fill the stock tanks to wakeboard, so I'm not overloading it.  I do run at high speeds (WOT) to get to certain places and sometimes running near WOT for 15-20 min.  I've been reading about the GM engines 07-10 and some of the forums talk a lot about the piston and ring issue which causes blow-by and oil consumption.  Wondering if I have that. 

I would like to clean the engine but have never done that.  Anyone have any tips on cleaning Piston and rings or sludge.  I noticed on Bakes they have a GM piston and ring cleaner but it's like $100+.  Plus, I don't know prev owner upkeep so I would really like to clean clean clean the engine.  Anyone have any tips on the process of cleaning inside of engine.

FYI, I've been running a can of sea foam upon every fill-up with this engine and running 93 octane.  Maybe overkill, but I don't mind.

Edited by hawaiianstyln
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I tend to a agree with your dealer, it's normal.  Some use more oil than others.  At high RPM, WOT, the rings have the hardest time controlling oil.  You have to remember this engine is just a truck engine, repurposed for a boat, not really designed with prolonged high RPM use in mind.

If it were me, I'd just add that monthly quart and not worry about it....

One more thing, that extended high RPM use degrades the engine oil's viscosity modifiers.  You might want to consider running straight weight oil.

Edited by MadMan
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I have used Seafoam with good results . But I would look to see if its ok with A catalyst engine.  I said in another post I have no experience with this motor but  I think they must have very low ring tension or having ring flutter. Just no good reason to not control oil use today. Its not good for cats, fuel economy and loss of H.P.  

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59 minutes ago, shawndoggy said:

he says he doesn't surf.

Are the WOT runs mandatory?  I'd chill on that (cruise around 4k) and I bet a lot of the consumption goes away.

nah WOT's are mandatory, I will chill on those.  Good idea

 

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would it still be okay to do some sort of engine flush?  Engine cleaner?  Dump some sea foam in the oil?  Anything I can do to do some cleaning would make me feel comfortable.  I don't mind spending the extra money for cleaners, it can only be a good thing right?

Thanks TMC for the info!

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@hawaiianstyln:  Have you looked at the plugs, poked a borescope in the combustion chamber or pulled an exhaust manifold to see if there is any carbon buildup you can see?  Your WOT runs probably burn off any deposits.  I would conclude that your WOT running is the RPM / load condition that is the primary contributor to your oil consumption and as noted is due to ring flutter at high RPM.  I would also check your oil level after a hard run, look at the level and look to see if any air bubbles on the dipstick, if yes you are aerating the oil which will contribute to oil consumption.  What weight oil are you running?  Is your breather system as is should be, at WOT you may be creating a vacuum that would suck oil down the intake system.

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Plugs looks great!  I have not borescoped or pulled manifold.  I will say we do a lot of WOT runs.  Breather system is good if you mean PCV valve and K&N?  I checked PCV and cleaned it even tho it shook fine.  K&N has a new cleaning on it.

 

IMG_1728.jpg

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I remember seeing some block cleaner products years ago that you would add to your oil to clean the gunk out.  It was probably just mineral spirits with some detergent in it.  Do they still sell something like it? 

I would not have a problem with running that stuff for a few minutes before an oil change if you really think you have a lot of buildup.  I have used straight mineral spirits before in a smaller engine. 

But I have to agree on the WOT part.  Maybe Most Open Throttle (MOT) for you for a few outings to see if that's the solution? 

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I know bakes sells this "Indmar Piston & Ring Cleaner" but have no clue about it.  Says it's for a 383 Hammerhead but I don't see why it can't be for Monsoon 340.  I don't even know how to tell if I have sludge. 

Maybe I will try a little Sea Foam in the oil for starters, but I'm hesitant to try this stuff:

https://www.bakesonline.com/indmar-piston-ring-cleaner.html

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2 hours ago, hawaiianstyln said:

I know bakes sells this "Indmar Piston & Ring Cleaner" but have no clue about it.  Says it's for a 383 Hammerhead but I don't see why it can't be for Monsoon 340.  I don't even know how to tell if I have sludge. 

Maybe I will try a little Sea Foam in the oil for starters, but I'm hesitant to try this stuff:

https://www.bakesonline.com/indmar-piston-ring-cleaner.html

I'm not much into these "snake oils",  but since that piston & ring cleaner is a GM product, maybe you can find a cheaper source.

 

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