Merc oil vs Mobil 1

[craze1cars]

Re: Merc oil vs Mobil 1

I always find it fascinating that Volvo has completely different recommendations from Mercruiser. Yet they run the EXACT same GM engine blocks.

Here's what my 1999 5.0L GL Volvo manual explicitly recommends (very slightly paraphrased to save me some typing):

"Either use Volvo Penta Duraplus, OR any good quality oil CE/SG or better that meets GM Spec GM-6094-M." Sooo...what the heck is that??? This link gives a 4 PAGE LIST of SPECIFICALLY APPROVED GM MOTOR OILS which meet that spec:
http://www.gm.com/corporate/responsibility/environment/maintenance/gm_approved_engine_oils.pdf

I'm pretty sure you'll find your Mobil 1 on that list...along with pretty much every other brand of oil ever produced.

Which means the only remaining question is one of viscosity. And in my Volvo manual, for any boating temps above 32 degrees F, they recommend ANY of the following viscosities?again in no particular order:
SAE 30
SAE 20W-50
SAE 15W-50

Isn't owning a Volvo nice? They let you use pretty much ANY brand of oil you like, in NORMAL and easy-to-obtain viscosities, and they don't make you feel one bit bad about not buying theirs. Heck, they don't even recommend their own oil OVER the others. They just say ?use ours OR any of these?? and they put it in writing right there in your owner's manual.

So if any of you think your Mercruiser engine might be just a tad bit similar to my Volvo engine?then I feel pretty comfortable following VOLVO's recommendations (which is cheaper and easier to obtain), and throw out Mercruiser's recommendation of their proprietary and expensive and inconvenient to purchase 25W-40 stuff...

My personal choice? My I/O's (both Mercruiser and Volvo) have always run and will continue to on Mobil 1 15W-50...BECAUSE VOLVO SPECIFICALLY RECOMMENDED IT TO ME in my Volvo owner's manual, and which is sold at Walmarts everywhere in 5 quart jugs for about $25.

I love oil questions. Always fun in so many different ways. Quite certainly someone will chime and and tell me my Volvo manual is wrong?and that I should be running teak oil..

Now let's talk about Gimbal bearing grease. Guess what Mercruiser recommends: MERCURY UNIVERSAL JOINT AND GIMBAL BEARING GREASE. Guess what my Volvo manual recommends? ANY EP rated wheel bearing grease!! And guess what? My Volvo Penta SX specs the EXACT SAME GIMBAL BEARING PART NUMBER as my Mercruiser Alpha 1 does. But they somehow need different types of grease?? Yeah...sure they do. So when all my Gimbal bearings need greasing, I grab the exact same grease gun I use to grease the tie-rods on my pickup....why? BECAUSE MY VOLVO MANUAL SPECIFICALLY RECOMMEND THAT I USE IT. Yet Mercruiser doesn't want you to acknowledge this option...makes it hard for them to sell $7 mini-tubes of special grease if they do that.

Gear oil? My Volvo manual specifically recommends Mobil 1 75W-90 gear oil. Of course I freely acknowledge that my Volvo drive is completely different from Mercruiser drives. But somehow I doubt that matters at all...since none of the other Mercruiser lubricant recommendations hold water with me...based on what Volvo recommends for the EXACT SAME ENGINES AND PARTS that these powerplants utilize elsewhere...

It's all funny to me.

 

[jaxnjil]

Re: Merc oil vs Mobil 1

craze1; the reason for the difference is the black engine enhancing paint on the merc's
to be able to run these oils in your merc you have to also paint your block red

thanks for your post, and makes sense to me.

 

[Fireman431]

Re: Merc oil vs Mobil 1

...Wait a minute here...We're supposed to check and change the oil!!??

 

[300sflyer]

Re: Merc oil vs Mobil 1

Just to throw a monkey wrench in this discussion, my remanufactured Mercruiser 357 engines, call for Mercury 25w40 Synthetic "blend" engine oil right from day one for break-in, and after the 20 hour break-in period. Why do they specify this one? ... I have no idea.

http://www.mercurymarine.com/otherproducts/maintenance/syntheticblend.php

 

[45Auto]

Re: Merc oil vs Mobil 1

I always find it fascinating that Volvo has completely different recommendations from Mercruiser.

Here's what my 1999 5.0L GL Volvo manual explicitly recommends (very slightly paraphrased to save me some typing)

Heck, they don't even recommend their own oil OVER the others.

Maybe Volvo has gotton smarter this century, or maybe your paraphrasing left out a little. Here's the actual oil recommendation for the Volvo 8.1L from Volvo Penta

http://www.volvopenta.com/volvopent...lication_search/Pages/publication_search.aspx

vs the Merc 8.1L recommendation from Factory Manual #30:

Notice how Volvo RECOMMENDS that you use their oil? (recommendation in the lower left corner under the viscosity chart, and also in first paragraph on the right). They want you to use other oils ONLY if their oil is not available. Same with Merc.

Volvo can't even make up their mind what they want you to use if you don't use their oil. Their top recommendation is straight 30W above 32 degrees, straight 20 from 32-0 degrees, and straight 10 below 0 degrees. Then they recommend a multiviscosity synthetic below the temp chart if their oil is unavailable, but the second paragraph from the bottom on the right reads:

Use single viscosity oils in markets where available. The use of multi-viscosity oils such as 10W-30, 10W-40 is not recommended unless single viscosity oils are not available

Sounds a lot like the Merc recommendation, doesn't it???

Have you looked at that GM spec on the approved oils you posted?

This link gives a 4 PAGE LIST of SPECIFICALLY APPROVED GM MOTOR OILS which meet that spec:
http://www.gm.com/corporate/responsi...ngine_oils.pdf

The HEAVIEST multi-weight oil on your approved list above is 10W-30. Most of them are 0W-30 or 5W-30. There is nothing close to the 15W-50 or 20W-50 Volvo recommends if their oil is unavailable. Either Volvo is screwy or GM is screwy (but I bet GM's recommendations are based on automotive service conditions, NOT marine service conditions).

Don't you wish you owned a Mercruiser so you could at least figure out what oil the factory wants you to use?

 

[QC]

Re: Merc oil vs Mobil 1

Weird that link says Outboard oil . . .

 

[QC]

Re: Merc oil vs Mobil 1

I forgot my favorite thing to add to these threads: Does anybody know anyone who has had a Marine engine fail due to lack of lube blamed on the oil? . . . Hmmmmmmm.

 

[jaxnjil]

Re: Merc oil vs Mobil 1

I forgot my favorite thing to add to these threads: Does anybody know anyone who has had a Marine engine fail due to lack of lube blamed on the oil? . . . Hmmmmmmm.

good point qc.

especially given the play these type threads get.

 

[Don S]

Re: Merc oil vs Mobil 1

I forgot my favorite thing to add to these threads: Does anybody know anyone who has had a Marine engine fail due to lack of lube blamed on the oil? . . . Hmmmmmmm.

I don't know of anyone, and after 30 some years of working on these %&*@$&# boats for a living and seeing countless numbers of dead engines. None have been because of using the wrong oil.

 

[Merc4ever]

Re: Merc oil vs Mobil 1

I'm so confused now Merc says I have to use 40w when the air is over 50 deg. But in the same motor Volvo says use 30w when it's over 32 deg. I really want to do what's best for my old motor to get the most life I can out of it. What am I to do?

We have made some progress though both Volvo and Merc say don't run 10-30 or 10-40

 

[QC]

Re: Merc oil vs Mobil 1

I don't know of anyone, and after 30 some years of working on these %&*@$&# boats for a living and seeing countless numbers of dead engines. None have been because of using the wrong oil.

And I was literally going to exclude you from the question . . . I have never seen one in the truck biz either. Running them out of oil is bad no matter what you use. There's a useful tip for anyone hoping to learn something from this thread . . .

 

[45Auto]

Re: Merc oil vs Mobil 1

Does anybody know anyone who has had a Marine engine fail due to lack of lube blamed on the oil?

All of my engine failures have been due to lack of lubricating properties from the oil. Doesn't matter that it was turning 6500 RPM with 20 inches of boost, the block was cracked because I didn't winterize it, it had no water because the impellor was shot, and it was 30 years old with piston slap so bad you couldn't hear the radio. If that %$#^$%#@# oil had been any good those rods wouldn't have come through the side of the block!

 

[wca_tim]

Re: Merc oil vs Mobil 1

One way to have an idea what you're oil is doing in the context of the bearing clearances in your engine is to take the oil pressure off the front of the bock... you may not be able to tell a great big difference between 30 wt anf 15 - 50 with the sending unit above th oil filter, but I'll tell you on mine there's a HUGE difference whithout the large thermostatted oil cooler that's on it now... that's on an engine that's built more like a circle track engine than a car engine with a marine cam... but the same principle applies...

like everyone's said, as long as you don't run thin oil in a regular engine, and you don't put the hammer down until the engine is up to operating temp, and lastly you check and change the oil, it'll probably be fine...

 

[craze1cars]

Re: Merc oil vs Mobil 1

Maybe Volvo has gotton smarter this century, or maybe your paraphrasing left out a little. Here's the actual oil recommendation for the Volvo 8.1L from Volvo Penta

LOL! I just KNEW someone would chime in and tell me my owner's manual was wrong!!

I don't have a scanner...but God's honest truth, My parapharsing left out very very little.

What you posted for 8.1L is simply worded quite different from what my 1999 Volvo 5.0GL owner's manual says...and I agree with you totally that's pretty annoying!

The good news is, your version still says it's perfectly acceptable to use "pure synthetic 15W-50" in their little chart...which agrees with my manual's chart...and which is exactly what I run. And I will continue to do so indefinitely. I agree they clearly put priority recommendation on their own Volvo oil in your manual...and I assure you that my manual definitely does NOT word it with ANY priority such as the one you quoted...so it seems they indeed can't make up their mind...


I really like Don's (and QC's) last statement, and I think it speaks volumes. IMO, the type of engine oil is probably THE most over-analyzed and over-debated non-critical item on ANY of these boats. And cars. And motorcycles. And lawnmowers. And snowmobiles.

No matter what oil ANY of us chooses to run, I bet pretty much ZERO of us will ever have a failure that relates directly to improper lubrication due to the TYPE of oil we choose to run.

Which again is all the more reason to NOT WORRY about buying the lovely Mercruiser 24.98W-40.321 oil that they seem to always insist on...

Feel free to run anything remotely close to that, AND FAR MORE IMPORTANTLY follow the recommended maintenance timetable and storage procedures, and I believe your engine will live a long and healthy life.

 

[QC]

Re: Merc oil vs Mobil 1

All of my engine failures have been due to lack of lubricating properties from the oil.

OK, so we all collectively know one . . .

 

[Don S]

Re: Merc oil vs Mobil 1

Originally Posted by 45Auto
All of my engine failures have been due to lack of lubricating properties from the oil.

Sure, you blew the engine and you had just changed your oil 15 years ago, right?

What I am saying is this..... You change your oil and filter regularly, to the manufactures spec. of every 100 hours or yearly (Which Ever Comes First), oil type, maker, or weight, will not be the cause of your engine failure.

 

[JustJason]

Re: Merc oil vs Mobil 1

What I am saying is this..... You change your oil and filter regularly, to the manufactures spec. of every 100 hours or yearly (Which Ever Comes First), oil type, maker, or weight, will not be the cause of your engine failure.

It also doesn't hurt to actually check it every once in a while in between oil changes either.
Just because you don't see dirty oil in the bilge doesn't mean that the engine is not low on oil.

 

[Merc4ever]

Re: Merc oil vs Mobil 1

I guess my final decision for this years oil change is gonna be straight 40w based on ambient temps over 75 deg. and the fact the purchase is close to home. 30 is to thin according to Merc.

 

[craze1cars]

Re: Merc oil vs Mobil 1

I guess my final decision for this years oil change is gonna be straight 40w...over 75 deg....30 is to thin according to Merc.

And yet as you seem to have already noticed...in 45Auto's quoted charts above: According to Volvo...straight 30 is 'recommended' for that temp range, which indicates 30 is NOT too thin for above 75 deg. And Volvo never even suggests that straight 40 should be considered an alternative at ANY temp...I suppose it is presumably too thick???

Note Volvo does stipulate that any straight 30 (first choice) or 15W50 or 20W50 (2nd choices) you choose to run MUST be PURE SYNTHETIC...written in BOLD. While Mercruiser seems to think the regular straight 30 and 40 stuff made outta crushed dinosaurs is OK...albeit rated way down as their 5th choice.

All for the same GM motor, run in the same marine application, at the same RPM...etc.
but these 2 very reputable mfrs continue to offer completely different oil recommendations...

I believe this is one of many reasons why there will NEVER be an end to oil questions. AND why the oil an individual selects really doesn't matter at all for the performance and longevity of the motor.

Just pick one and roll with it...yer motor will be fine...

 

[Merc4ever]

Re: Merc oil vs Mobil 1

It would be nice if we could all get together with GM and have them tell us "yeah the absolute best oil to run in your boat in the summer temps is _______w."

I read some of the engine tests like:

http://www.performanceoilnews.com/oils_against_oils.shtml

and wonder maybe what is best is what is the slipperiest that wont break down at the temps we operate. Yet thin enough to start easily for those far from home cold starts.