Did Volvo change the recommended oil from 30wt?

[mr 88]

The old style cutlass, is made of leather, so it swells when wet. It should leak a few drops every so many seconds when the shaft is turning. These drops is how it is adjusted (tightened). For the most part it will not leak when shaft is not turning, unless the leather is worn out and needs replacing.

New style are called drip less and uses to stainless steel plates and carbon disk which is also cooled by water tube to the unit

Uhhh a cutlass bearing is located underwater mounted to the strut. The prop shaft runs through a plastic sleeve aka bearing that is attached to the strut. There is a groove cut in the " bearing " to allow water to flow through the "bearing" and lubricate it so it doesn't burn up from.the friction of the prop shaft.. Now a dripless shaft seal is a different animal and not to be confused with a cutless bearing.Not that this has anything to do with oil.

 

[USA_boater]

Really? You are again asking more oil questions?

:facepalm:

Yeah, always happens when I get something new (to me) that takes motor oil...last time it was my lawn tractor...the flat tappets and the new API CK-4 rating made me lose sleep LOL. I'll get through it with you guys' support...my name is...and I'm an oil-aholic

Seriously though, I think I have it licked...For my Merc Outboard I have to run the factory oil for warranty...But I think once warranty is up, I will just run T5 15w40 in both boats, tractor, push mower, and generator. It will be nice not to have to buy 3-4 different oils anymore. I'll prob even take the 15w50 M1 back for exchange too...40wt should be fine and the guy with the overheated 4.3 on 20w50 bugged me just enough. Plan B would be to switch the VP to the same oil as the Merc (25w40) if someone convinces me the FC-W will make that much diff on a 14yo inboard.

 

[Lou C]

Ok here is my take on this....with marine engines, you have a lot of shear due to the sustained high rpm use. Proof is...I look at my Oil Pressure gauge on my old '88 4.3 V6..... cold idle oil pressure is about 45 psi, after running on plane, it will drop to about 15-20 psi...on our '98 Jeep with the 4.0...cold oil pressure is about 45-50, hot....it never drops below 30 psi....

I think the recommendations that Merc, OMC and Volvo have this in common...they tend to specify oils that do not use viscosity index improvers....think about it...single weights do not use them...syn oils do not need them....and Merc claims their 25/40 does not use them either. So....the Rotella or Delo 15/40....if not the syn version...more than likely uses VI improvers....
the issue being when they break down....you wind up with a lower viscosity oil....
But....without used oil analyses....we are still guessing.....that would be a nice section to add to iboats….like bob is the oil guy....specific to marine engines....actual user tests....to eliminate guessing.....about what really works.....

 

[USA_boater]

I left BITOG almost a decade ago and haven't been back. Lou, I am aware of all of what you said except the part that synthetics didn't use VI's...I'm not sure that is true across the board but i knew they could use less? Anyway, Mercury says their 10w30 conventional is fine for ALL temps including up to and over 100*F ambient temp. For the reasons you mentioned, and 6k RPMs wide-open, I didn't want to use 10w30 and have it shear.

On my Volvo Penta, since it is run only in warmer months, I was curious if/why they changed the spec because 30wt would seem like a good choice; especially synthetic. I am currently running syn-blend 15w40 in the Volvo and since it doesn't tun as high of RPM's as the outboard and will be changed yearly, I figured it would never shear below a 30wt before it was changed.

 

[QBhoy]

Oh there is a lot of strange info on this post

 

[Shaper79]

10-30. Of your favorite oil. Pluse 1 quart of Lucas pure synthetic. My motors love it. Extremely smooth and quite. And no more dry starts.

 

[USA_boater]

does the Lucas change the viscosity? I've used their conventional oil stabilizer for high mileage engines and gear boxes and I'd say it made the oil thicker for sure...no sure about their synthetic oil stabilizer though?

 

[dypcdiver]

How long ago did GM design and build this engine?
I wonder, when they made their original oil recommendations what they knew about the 50+ years of oil research and technology of today.
It never ceases to amuse me when people say use the oil that was recommended originally, dismissing 50 years of research.

 

[Scott Danforth]

does the Lucas change the viscosity? I've used their conventional oil stabilizer for high mileage engines and gear boxes and I'd say it made the oil thicker for sure...no sure about their synthetic oil stabilizer though?

you are seriously over-thinking the oil. stop with the additives and other things, get a good oil, go boating.

 

[Lou C]

Agreed! Straight 30 if you can find it is fine, 15w/40 is fine, Merc 25/40 is fine, even straight 40 if in a hot climate, is fine. Those are the ones I'd use. Make it simple....The advantage of the 15w and Merc oil is somewhat better cold cranking if you boat where it gets cold in the end and beginning of the season.....

 

[Scott Danforth]

Lou...what is the beginning and end of season that you refer to......LOL

 

[USA_boater]

Well I have the 15w40 in now but still have a jug of 15w50 synthetic on the shelf and was hoping that upping to 15w50 would not be too thick. thanks

 

[GA_Boater]

Are you even using your boat with all the oil changes and worry about 10 points of viscosity? Oil engineers don't fuss this much and that's what they get paid for.

How can you have fun on the water staring at the oil pressure gauge?

 

[jimmbo]

It is your engine, run whatever you want. You have had other threads on the same subject. You just keep asking the same questions, hoping you will get somebody to agree with what you have already decided to do

 

[USA_boater]

It goes like this:

1.) I buy a 14yo used boat at the end of the summer as my 1st boat that sat for 5yrs un-used with God knows waht oil in the crank case

2.) I have to do a lot of work in a short period to be able to use it at least some before the season ended and discovered despite the 30wt synthetic on the oil cap, that Volvo doesn't make that oil anymore and "might" have changed their recommendation - so I choose 15w40 Rotella syn-blend in a pinch so-as not to hold up the oil change

3.) After I change the oil (and filter), I commit that I'm at least going to use full-syn next time, since that's what Volvo recommended (regardless if they changed the viscosity). So I get a 5-gallon jug of Mobil-1 15w50 for half-price ~11 bux or something like that.

4.) I read someone on this forum say that running 50wt multi-viscosity oil hurt their 4.3 motor somehow. So I then wonder if the jump from 30wt to 50wt is too much.

That's about how it went...I'll just run the 15w50...the boat is too old for me to obsess about FC-W and I like being able to get the oil locally. So for a full-syn oil, my choices are rather limited locally. Otherwise I'd probably just run the Quicksilver 25w40 blend since the boat is a warm weather boat. Thanks.

 

[Lou C]

The only think I have ever heard was that 50 wt was too heavy for the cam gear that drives the distributor but I think Merc also recommended 20/50 in the past so it is probably just fine.

I used the Merc 25/40 oil because:
my engine had a bad overheat in 2013 it survived that with the Merc oil in it
ran 2 more seasons, then blew both head gaskets, and survived that (salt water no rust in engine) with the Merc oil in it.
replaced the heads (both cracked, eroded cooling passages) with re man heads last year. Put the Merc oil in it again, why because I had good luck through two big engine problems over the past 5 years.

 

[USA_boater]

Thanks for the feedback, were you using the conventional or syn-blend Merc 25w40?

 

[Lou C]

Conventional. The short block is original (1988).