Mercruiser Marine 20W-40 Full Synthetic oil

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car54

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I sent a sample of $13+ per quart Mercruiser Marine full synthetic 20W-40 Low Phosphorus Emissions Control oil in for a VOA sample.

I purchased a 2013 Mercruiser with a 4.3MPI catalyst engine and I'm interested in running something cheaper but still running the best oil possible. I figured nothing special with this stuff, but let me know your thoughts.

mercvoa.jpg


mercoil.jpg


mercmpi.jpg


Modern cars run oils with much higher additive levels and catalysts never get poisoned. This boat hasn't used a drop of oil yet.. seems like a ploy to make me buy $$$$$ oil.
 
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I ran amsoil 15w-40 diesel/marine in my 4.3 Mercruiser for 10 years and a lot of hours. Hard to beat and decent price
 
Originally Posted By: AlienBug
Guess the question is: How much do you trust a $20 analysis to give you the full picture of an oil's quality.


It's a 4.3 GM engine. We put thousands of hours on a Mercruiser 888 (302 Ford) running VWB and the engine out-lived the boat.

Mercruiser oil isn't Unicorn urine. And it certainly isn't better than OTR truck HDEO lubricants IMHO.
 
They put a lot of emphasis on the catalyst health... I know it's a normal engine, but would it really ever burn enough oil to cause issues?

I was considering running Mobil1 turbo diesel truck, or 15w-50 gas engine oil, Rotella T6, or even Schaeffers S9000 5w-50.

I just want the best.. and the merc oil certainly doesn't seem to be anything special.
 
Originally Posted By: car54
They put a lot of emphasis on the catalyst health... I know it's a normal engine, but would it really ever burn enough oil to cause issues?


probably have the EPA to thank for that...they mandated 120K catalyst life in cars and ZDDP went down. don't know what it is in boats, but probably something similar in hours.
 
Thanks for the report.

At $13 per quart, that oil is a little pricey. Mobil 1 0W-40 has a similar viscosity, better detergent package, and is only $5 per quart (in the 5-quart jug at Walmart).
 
Originally Posted By: OVERKILL
Mercruiser oil isn't Unicorn urine. And it certainly isn't better than OTR truck HDEO lubricants IMHO.

Absolutely. With it labelled as a low phosphorous oil, I was expecting the VOA to show something like that Titan Fuchs or whatever it is we saw before. Instead, we see a 20w-40 (good grief) with GF-5 additive levels, which, incidentally is what most 40 grades on the shelf have in the first place, except for HDEOs.

As 147_Grain indicates, this is better than M1 0w-40 how? In any case, one has to pay attention to the manufacturer's recommendations. I'm assuming they're not calling for a GF-5 oil, or they wouldn't be having you use a 20w-40.

So, what does the manual actually call for? If all it's asking for is something in a 40 grade that's SM or better, there are plenty of choices without going "too cheap" if that concerns you. If it's calling for only the obscure 20w-40 grade, you might be stuck.
 
EPA emissions warranty is 3 years or 480 engine hours.

This is the page spelling out engine oil requirements. I have no doubt M1 0w-40 exceeds all requirements for this engine and have no problem voiding the warranty using it.

mercbook.jpg
 
Its actually stronger than I thought it would be...a lot of specialty oils like this are a lot of hype and not much substance.

Also a lot thinner than I thought it would be - thought it would be solidly in the 40-weight range (15cst +).
 
Originally Posted By: AlienBug
Guess the question is: How much do you trust a $20 analysis to give you the full picture of an oil's quality.


What he said ^ ^ ^. My question is, what base stocks is the oil using? Boats run the engine at high output for prolonged periods, so localized high temps are going to be a bigger issue than in a typical automotive application. Unless the Mercruiser oil is using a POE base stock, it ain't worth $13 a quart.
 
Originally Posted By: 147_Grain
Thanks for the report.

At $13 per quart, that oil is a little pricey. Mobil 1 0W-40 has a similar viscosity, better detergent package, and is only $5 per quart (in the 5-quart jug at Walmart).


Typical outrageous markup with a "mandatory" warning for warranty compliance. They will try anything to chain you to their dealer network, at least for the duration of your warranty.
 
I think Steve hit it on the head. It looks like you're tied to an FC-W certified oil, at least during warranty. I'm not sure what's exactly "better" about these oils. They don't have abnormal phosphorous levels.

Oh well. The list of approved oils as of 2013 can be found here.
 
I posted a VOA for the Volvo 10w-40 a few months ago.

The Merc oil is made by Citgo.

The 30 weight catalyst oil by Volvo was an Amsoil product. But unknown who makes their 40 wt oil today.

Both Merc and Volvo only care about the life of the catalyst during the warranty period and that's IT. Time will tell how the engines fair with these oils.

What's amazing is that another company (indmar) who uses the same 6.0 engine as Volvo recommends 15w-40 SL pennzoil marine oil where volvo recommends 10w-40 and Ilmor recommends Mobil 1 5w-30 for their 6.0 engine
 
Car 54,

I had a quart of virgin Merc 20w-40 analyzed by Oil Analyzers in Nov 2012 for comparison between the two companies.

Iron - 1
Silicon - 2
Sodium - 35
Potassium - 8
Moly - 10
Boron - 1
Magnesium - 19
Calcium - 1959

Phosphorus - 681
Zinc - 776

Viscosity @ 100c - 13.8
 
so the phosphorus, zinc, and viscosity all look similar.

The funny thing is the 20w-40 synthetic doesn't appear on the FC-W certification list, but is sold as such.
 
Yes, it's on the approved NMMA catalyst approved oils.

Another oil I'm thinking of using in my engines is Amsoil XL 10w-40, but rumor has it that Amsoil is coming out with a Catalyst approved marine oil.

I've used the regular marine 10-40 from amsoil, but way too much zinc and phosphorus in that oil to make the boat engine catalyst survive.
 
how different is a boat catalyst from a car catalyst?

my cars burn oil... catalyst still works fine.

I seriously envision the manifolds rusting out before anything happens to the catalyst.
 
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