Oil selection

[bigbadchevy89]

04 4.3 gxi

Doing research on oil. Is marine grade full synthetic required?? I've always ran wolfshead in my my mercruisers with great luck this is my newest engine though just checking. I just purchased this boat and cannot read the writing on the oil cap any longer please help.

 

[kd4pbs]

OEM recommends SAE30 synthetic. Good luck finding that anywhere. I use Rotella T6 15w40.

 

[jimmbo]

The Marine Industry does have a Cert Standard for 4 Stroke Oils. FC-W. A lot of the Marine Engines, at least those with Raw Water Cooling do operate at lower Temps than a Car/Truck Engine, thereby subjecting the Oil to a Different set of Parameters. Of course there are those that think Oil is Oil... Their minds are Made up, any Facts only cause Confusion/Conflict. I wouldn't be surprised if they have tried Wesson Vegetable Oil...

 

[Lou C]

You can also use the Mercruiser 25/40 conventional or syn blend. I have used both & done oil analyses and they hold up well to marine use…

 

[Pmt133]

I've never had an oil analysis come back better using an oil other than what the engine was designed to run on. Just saying.

 

[Bt Doctur]

Rotella for flat tappet too

 

[Jeff J]

What does your owner’s and/or maintenance manual say? Owner’s manual should be available for download free somewhere.

 

[BRICH1260]

I`ve used Rotella T6 and Mobil 1. I would try to run full synthetic given a choice but I would not get hung up on "marine " specific oils.

 

[Scott Danforth]

an 04 4.3 is a roller motor. the motor shines with synthetic.

 

[kd4pbs]

While the marine engines do indeed have cooler water jacket temps than their automotive counterparts, I can assure you the oil temps - especially on those who don't have oil coolers - run much hotter than those in automobiles. This is where 100% synthetic shines. The diesel-oriented oil has lots of the good stuff for flat tappet engines as well, and it certainly does not hurt roller tappets.

 

[bigbadchevy89]

What does your owner’s and/or maintenance manual say? Owner’s manual should be available for download free somewhere.

I am trying to find that right now to download.

 

[bigbadchevy89]

Awesome thank you all for the great advice

 

[kd4pbs]

Owners' manual will tell you Volvo-Penta full synthetic SAE30.
NLA.
A slightly heavier oil will cost a little horsepower at the expense of less wear. Theoretically, a 10W30 will perform the same as SAE30 once it's at operating temps.

 

[Jeff J]

Owners' manual will tell you Volvo-Penta full synthetic

Or a full synthetic alternative.

 

[Jeff J]

I tried to attach the manual on my phone but the file is too big. It should be available for download on the Volvo Penta website.

 

[Jeff J]

I hope this is the correct page from the correct manual

 

[Lou C]

if Volvos spec is a full syn straight weight oil my guess is that they are concerned about the oil breaking down and losing viscosity. In that case I’d use the Mercruiser/Quicksilver 25/50 syn blend. It is probably the best oil they sell (expensive too) and has significantly more zinc (this I know from doing my oil analyses) than the conventional 25/40. Like 1250 ppm IIRC. I don’t think current formulations of Rotella has even that much; diesel oils have reduced levels of zinc also. And the roller cam does make it not such a big issue.

 

[kd4pbs]

What they mean is an alternative to their brand of pure synthetic oil. There is no such oil as a "full synthetic oil alternative" - it's either full synthetic, semi-synthetic, or conventional. Since Volvo Penta doesn't make their own oil, it's safe to write that there is no reason to use the VP branded oil. The Rotella T6 found today is SN rated and can be found at your corner neighborhood auto parts store, along with an oil filter that will serve just fine on a marine engine. All Sx rated oil is by definition backwards compatible with the lower rated oil requirements of yesterday. In other words, SN is compatible with all Sx ratings below "N"... SC, SD, etc. The thing is, mono-grade synthetic oil is basically non existent today.
Oh, I almost forgot... I got 2.5 gallons of T6 15W40 for under $70 at the local auto doodle. That's exactly enough for two changes in my 5.7 Gi. Not bad compared to what I have to feed my diesel Mercedes, or even the three gallons my Cummins drinks every oil change.

 

[kd4pbs]

if Volvos spec is a full syn straight weight oil my guess is that they are concerned about the oil breaking down and losing viscosity. In that case I’d use the Mercruiser/Quicksilver 25/50 syn blend. It is probably the best oil they sell (expensive too) and has significantly more zinc (this I know from doing my oil analyses) than the conventional 25/40. Like 1250 ppm IIRC. I don’t think current formulations of Rotella has even that much; diesel oils have reduced levels of zinc also. And the roller cam does make it not such a big issue.

Lou, it's hard to dig out the info but T6 has ~ 1200PPM zinc according to one guy's test done 14 years ago which he showed on that popular Bob oil guy's forum (he found 1251PPM). Since manufacturers change formulations more often now due to the EPA's recent historical overreach trying to justify their existence in a country now absent of the types of environmental issues they were originally formed to solve, there's no telling what it is today. That being written, my stinky, worthless opinion is that anything SN rated will have enough ZDDP for a broken-in relatively flat-tappet engine like the older marine engines we'd see. If breaking one in, use some non-synth break in oil - which should be used anyway to promote ring sealing, then switch to a decent full synthetic. If worried about ZDDP availability in the oil, use an additive. It is available.
Of course for newer engines with roller cams, it's a moot point.

 

[Lou C]

Yep the only way to know is to run a virgin oil analysis. I have a 98 Jeep with a flat tappet cam (4.0 six) and it’s been run on Valvoline max life 10/30 for years. And no issues with the cam or lifters at 182,000 miles..this oil has like 750-800 ppm of Zinc..on the Jeep boards they are always recommending this or that oil but much of this is just conjecture. Just do oil analyses, then you’ll know if the oil is good enough!