Not Another Oil Thread!! (It's Too Quiet In Here) |
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Jonny Quest
Grand Poobah Joined: August-20-2013 Location: Utah--via Texas Status: Offline Points: 2967 |
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Posted: October-24-2024 at 9:07pm |
My boat - 2003 Ski Nautique 206. 6.0L ZR6 engine. Current oil - Shell Rotella T6 15W-40.
Taken from: The official PCM Owners Operation & Maintenance Manual (printed Nov. 2002)Engine Oil Requirements for all PCM engines: Above 50° 15W-40 SJ Below 50° 5W-30 SJ Synthetic engine oils are not recommended for use in PCM Engines. Fast Forward to July 2019. PCM Service Advisory - Updated Specifications for Engine Oils For GM Based Enginies: 6.0L - 7.4L - 6.2L - 5.3L Use this new oil specification going forward: All Temperatures GM Dexos Gen 2 (a.k.a. GM Dexos 1 Gen 2) - 5W-30 Per the GM Dexos website, Dexos 1 Gen 2 means 0W-20; 0W-30; 5W-20 and 5W-30 (gasp! most of these are synthetic) However, GM Dexos 1 Gen 2 has been discontinued -- only to be replace by GM Dexos 1 Gen 3 Per the GM Dexos website, Dexos 1 Gen 3 means 0W-20; 0W-30; 5W-20 and 5W-30 (also synthetic) So, it seems that the 5W-40 SJ oil specified in the PCM Owners Manualis is now persona non grata.. It also seems that the statement: "Synthetic engine oils are not recommended for use in PCM Engines" has also been, ah, modified so that the synthetic oils are not only fully embraced, but are now the "spec" oil. For additional fun, there is also a GM Dexos R oil. Per the website, the only offering is Mobil 1 SuperCar in 0W-40 and 5W-50. GM Dexos website states that all the newer Dexos spec oils are backward compatible and may be used in the appropriate viscosity. So...does that mean that my 2003 6.0L ZR6 is suddenly at risk with that nasty, non-spec 15W-40 that was once approved? Since I operate Above 50°, is the 15W-40 currently in my engine going to cause me big trouble and should be changed to 5W-30? How about Dexos R in 0W-40 or 5W-50? 🤪 In the PCM service Advisory, there is this statement: These engines are designed specifically for use with GM Dexos Gen 2 formula engine oil. Curious that the GM Dexos formula came out in 2010 and then was upgraded in 2015. One might wonder how my 2003 6.0L engine was "designed specifically for use with GM Dexos Gen 2 formula" seven years ahead of the GM Dexos roll-out. It does cause one to scratch one's head. I have 6 quarts of Valvoline VR-1 20W-50 on the shelf. Maybe I'll use that. GASP! Not Dexos approved! Not even 15W-40! I doubt the boat will make it out of the harbor before the engine blows! JQ
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Current
2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11088 |
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I guess you could ask PCM to rewrite the thing into something that doesn't talk around in circles (for us simple minded types) And congratulate them on finally figuring out that synthetic oil is OK to use |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21182 |
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Personally, I’d just run a good 15w40, especially in an older 6L that had that specified originally. Something like Rotella or Delvac. I trend towards synthetics in pretty much everything these days.
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fanofccfan
Platinum Member Joined: December-13-2009 Location: North Bend NE Status: Offline Points: 1777 |
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My boats get 15-40 as well.
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2004 196 LE Ski 1969 Marauder 19 1978 Ski
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Tomrupp
Groupie Joined: October-14-2021 Location: MI Status: Offline Points: 81 |
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15-40 rotella for me too in the 351. I’m using the red Purolator filter because it’s paint matches the valve covers. If it blows up, we will rebuild it.
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Tom
94 Ski Nautique Open Bow 351 with Carb 95 Double Decker Aqua Patio with 50hp Honda (3 carbs). |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3748 |
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The Dexos Oils were formulated for the newer Direct Injected engines. Direct Injection sprays fuel into the cumbustion chamber, not into the intake runner as all carburetor and injection systems did in the past.
Direct injection was just getting popular around 2010. GM introduced in on the LS engines later, maybe 2015? Direct injected engines tend to build carbon on the intake valves eventually forming a Tpee like carbon build up that chokes off the intake valves. Normally happens between 100,000 and 150,000 miles. There are techniques to clean these and the problem is common on all makes that are direct injected. Dexos oil helps reduce the carbon build up. If your engine is older and not Direct Injected Dexos oil is not needed. I am not aware of any other advantages to the Dexos oils. Direct injected Gasoline engines run fuel pressures of 1,500 PSI but it varies by RPM. The older fuel injected engines run much lower PSI, maybe 65 PSI but these shoot fuel into the intake runner and keep the intake valve clean. ( Diesel Direct Injected engines are running up to 30,000 PSI )
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21182 |
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For GM V8’s, Direct Injection came with the introduction of the LT. The LS never went DI. For the purposes of this discussion, will limit it to PCM marine engines: LS = 2003-current 6.0 LT = 2015-current 5.3 and 6.2 Question is regarding an (older) LS, so non-DI. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11088 |
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So.....I figure Jonny just read a thread on PN with this bulletin mentioned again and comes here to ask questions/stir things up.
link
Seems like everybody agrees that he doesn't need Dexos oil of any kind. It also seems that Jonny has never paid attention to PCM recommendations for oil and transmission fluid in any of his boats, based on past posts/threads. He has his favorites So why start now Jonny? Just because it's quiet around here? It's gone 21 years with oil that doesn't have Dexos as part of it's name. |
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MrMcD
Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3748 |
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You are correct Tim, sorry for any confusion, when I think of GM V8's it is the traditional old school small block and big block and then the switch to the LS style in 1999 with all the upgrades and many many options over the years. DOD, variable valve timing and then Direct Injection. With each model the power goes up.
I am waiting for the new 6.6L Truck gas engine to land in the boats. Maybe it already has but they are out of my price range for a toy.
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Jonny Quest
Grand Poobah Joined: August-20-2013 Location: Utah--via Texas Status: Offline Points: 2967 |
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KENO is correct -- I never paid much attention to certain PCM recommendations for oil/ATF specs. Maybe it will come back and bite me in the ass some day, but that day is not today. I was kinda bored last night and started thinking about the upcoing winter lay-up. Just for giggles, I looked at the PCM engine maintenance manual and then at the PCM Service Advisory. I was quite amused at how the oil recommendations seemed to run in circles: - No synthectic oil...Wait! Synthetic oil is now recommended. - 10W-40 oil...Wait! Don't use that! Use 10W-30 - Engines were specifically designed for Dexos oils...Wait! Some engines were designed and built years before Dexos oils To my lizard brain, it seemed a bit silly. I know that some people get all worked-up about oil, oil specs, viscosity, additive packages, ZDDP, etc. I can't remember ever hearing about, or seeing a blown-up engine due to running an oil that was reasonable, but not the exact specified oil. I also get a chuckle over how C-A-F-E impacts the oil spec for automobiles. Maybe I'll call Bob. He is, after all, the "Oil Guy" JQ
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Current
2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21182 |
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Manuals are typically model year specific so varying recommendations may have been driven by real changes in design. Remember that emissions systems (including cats) have evolved over the time period in question.
I never understood PCM’s recommendation against synthetic engine oil- though it may have been the association with longer OCI’s they wanted to distance themselves from. I think it boils down to the fact that the LS will be fairly oil tolerant (no need for super high levels of zddp etc) and since the weight recommendation in place when your specific engine was designed and built was 15w40, that seems like a pretty safe choice. I know that’s what I’d run. 5w30 seems pretty darn light even for colder weather use, especially on a closed cooled engine. |
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wayoutthere
Senior Member Joined: February-28-2020 Location: Florida Status: Offline Points: 452 |
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I read an oil article about the sn sm api gl rating. Wish i could find it again it gave ppm for newer oils and most were compatible with older flat tappet engines. Additives were said to be overkill when used in stock engines ( don't know if these351 operates in conditions that require all that.
(flat tappet oil requirements is what got me looking)because of the 1990 car i got and all the mobil 1 hype has me wondering if the old engines ran and were designed to run on conventional oil, what are the benefits besides saying your spending more. My 2003 f150 calls for 5w 20 and i run motorcraft or valvoline My 1990 chevy corvette calls for 10w30 and i have valvoline comventional oil ready for it's next change because no one can show me conventional oil can't get the job done. Problem i have is the sales/marketing, keep the hype, tell me straight, show me the math and i'll buy it. If you have to sell it, nobody most likely wants or needs it. So an api gl or what ever the rating system is currently known as says if your engine calls for sg, sg is obsolete and the next or newest combo sl is compatible in conventiomal oil and has 'x' zddp which is enough for flat tappet etc etc (for example) , maybe not for hi pressure hi stress, hi heat, performance engine like that 496 i had and ran valvoline vr-1 20w50. Wish i understood it or it was labeled as good for stock production engines manufactured between 1970 and 1980 etc and so on like this oil is rated to just keep pouring in the big block dump truck you never service and work the piss out of |
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uncle-buck
Senior Member Joined: June-14-2004 Location: United States Status: Offline Points: 324 |
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PCM has produced some fine products, but may not win any awards for writing manuals.
From the Engine Owners Manual that came with my 1990 SN: I have run conventional 10W-40 for most of the engine's life and began adding ZDDP a few years ago. No oil related problems ever - except when I let the boat sit up for six years and didn't use it.
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1990 Ski Nautique (original owner)
PCM 351W with D.U.I. |
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RealDeez
Senior Member Joined: August-01-2019 Location: MI/IN Status: Offline Points: 131 |
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For what it's worth, my 93 Sport has 1500 hours on it and has always had Mobil 1 15W50 in it...
Carb is about ready for another rebuild and the ProTec was long gone before I got it... but other than that, still kicks like a mule. That seems pretty good. |
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Lake James, IN
93 Sport Nautique |
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