using automotive oil for a 4.3 stern drive

[Capt Ken]

Re: using automotive oil for a 4.3 stern drive

So how many would think the OEM would reccommend anything other than the oil they are selling? Being every OEM is using the same GM engine, just painting it a different color, why does each OEM require a different oil? A good straight weight oil of good quality will work in any marine engine.

 

[TheOilDoc]

Re: using automotive oil for a 4.3 stern drive

Originally posted by Robby6950:<br /><br />So, OilDoc, and whoever else would like to comment, what is your opinion of using Shell Rottelo(sp)Diesel 15-40 in a 350 GM

Mercury specifically recommends not using polymer-chained, multi-viscosity oils in their marine engines. I have explained why above. Additionally, 15W-40 is not one of their recommended viscosities. <br /><br />However, Shell's single grade oils such as their Rotella T straight 20W, 30W, and 40W oils carry the API gasoline engine rating, and they also fall under Mercury's specified viscosity. The Rotella T 15W-40 is much different than the Rotella T single grades. As one example, the 15W-40 will contain 32% more sulfated ash than the straight 40W. Sulfated ash can cause engine build up, especially when idled in the cooler running 140'F Mercruiser. Diesel oils aren't always the best for gasoline engines. Running a non-recommended oil type and viscosity would not be my personal choice.<br /><br />

Originally posted by Capt Ken:<br /><br />So how many would think the OEM would reccommend anything other than the oil they are selling?

Mercury recommends several grades of oil that can be bought in many non-OEM brands. They recommend their unique 25W-40 oil first and foremost, because they believe it is the best oil for marine use. I respect the fact Mercury knows marine engines and what oil they need.

 

[tommays]

Re: using automotive oil for a 4.3 stern drive

oildoc dont confuse anybody with facts they just want somebody to tell them it is ok to use what every oil they want to believe is better than what is recomended<br /><br />tommays

 

[LubeDude]

Re: using automotive oil for a 4.3 stern drive

Found this on another forum and Its pretty much how I see it also.<br /><br />"CF-2 oils are Detroit Diesel (DD) two stroke single grades.<br />The new shear stable CI-4s in 10W30 and 15W40 multi-grades, I think, makes Merc's original recomendation of a CF-2 25W40 a little obsolete.<br />25W40 is a single grade SAE40 that happens to pass SAE's 25W cold crank and flow tests. <br />Big deal.<br />Most modern SAE 40 CF-2 HDMOs formulated from group II base oils would likely pass a 20W flow test, but are not marketed as 20W40s.<br />The better CF-2 SAE 30s are likely 15W30s, but who cares?<br />The point is CF-2s are alegedly formulated without VI improvers, and are therefore and supposedly shear stable.....<br /><br />I believe the risk Merc is trying to avoid is owners using cheap dino PCMO multi-grades."

 

[DHPMARINE]

Re: using automotive oil for a 4.3 stern drive

So many oils,so little time.I think any GOOD quality oil will work,and not hurt the engine.If you haul loads of fish,or barges maybe not.<br />I wonder if only one oil change a year is the best thing for the engine.With a car,used to be 3,000 miles 3 months.Oildoc,what happens to the oil sitting for a while?<br />DHP

 

[TheOilDoc]

Re: using automotive oil for a 4.3 stern drive

“C” class oils have little significance when discussing gasoline engines. API “C” designates “C”ommercial class or “C”ompression ignition diesel engine oils. “S” class oils are API designated for “S”ervice class or “S”park ignition gasoline engines. The Mercruisers being discussed here are gasoline engines.<br /><br />When discussing diesels (Mercruiser does have diesel engines), CF-2 class oils are not excluded from being multigrade oils. They are not always two stroke single grade oils. The Mercury 25W-40 is an example of a multigrade CF-2.<br /><br />The newer CI-4 class does not make CF-2 oils obsolete, nor does it supercede CF-2. CF and CF-2 are current specifications with their own unique applications. CF has superceded CD and CE for diesels using fuels that contain high sulfur content. CF-2 has superceded CD-II where diesel ring and cylinder scuffing is a factor. CF-4 is another different classification. CI-4 oils do not necessarily meet the requirements of CF or CF-2. The CF classifications will be listed separately on the container.<br /><br />The 25W-40 is not a single grade 40 oil. It is a combination of multiple grade oils and different base stocks.<br /><br />The API, along with ASTM, SAE, etc. have established industry standards for testing and classifying oil viscosity that go beyond cold crank and flow tests. The Mercury oil is listed as a 25W-40 because it meets those 25W-40 standards. <br /><br />It is unlikely that a 40W oil would pass 20W flow testing or meet the API’s requirements for a 20W viscosity, or that multigrade 15W-30’s are CF-2 30W’s.<br /><br /><br />

Originally posted by DHPMARINE:<br /><br />Oildoc,what happens to the oil sitting for a while?

Quality marine oils contain soluble additives that include corrosion inhibitors, antioxidants, and suspenders. The suspension additives keep the inhibitors suspended throughout the oil. They will remain suspended for extremely long periods of time. It would be important to change the oil before storage to remove the acids and contaminates from the engine, which cause corrosion and oxidation.

 

[f_inscreenname]

Re: using automotive oil for a 4.3 stern drive

A new Lubedude???? Say it aint so. I don't know if there is room in this town for two of them. Just kidding. Welcome TheOilDoc and Lubedude we’ll still love you.

 

[LubeDude]

Re: using automotive oil for a 4.3 stern drive

Originally posted by f_inscreenname:<br /> Welcome TheOilDoc and Lubedude we’ll still love you.

Well, Thanks, but we are not in competition, we just see a few things differently. There is room for two, (or more), some want a scientific approach, and some just want to know if it will work.<br /><br />So far we have managed to get along.

 

[WillyBWright]

Re: using automotive oil for a 4.3 stern drive

5W- or 10- Nothing! Straight weight is the way to go. SAE 30 has been used with fine results since the dawn of boating time. If you were to go synthetic you're stuck with the W's, so I'd go with the heaviest. You can split hairs forever on anything and everything concerning oil. If you want to cheap-out on oil, just get house-brand straight 30.

 

[Buttanic]

Re: using automotive oil for a 4.3 stern drive

Let's be realalistic here. Most gas engines will last over 100,000 miles in an automobile with reasonable maintenance. That would equate to 2200 hours of operation at an average speed of 45 mph.Most recreational boaters will put nowhere near this amount of time on a engine especially in the North with its limited boating seasons. I know some of you will say a boat engine operates at a higher speed but look at the RPM some of the smaller 4 cylinder cars are turning at 70 or 80 MPH. Some are near 4000 RPM. The hardest service on a engine is short trips that don't let the engine oil get up to temperature. Boats seldom operate this way. I know raw water cooled engines are run cooler but but it's oil temp that counts. It has to be high enough to vaporize dilutants and water. Boat engines operate in an enclosed space without air flow to remove some heat from the oil pan. Some have oil coolers but not all. Does anyone have an oil temperature gauge, most do not. Do you know what your oil temperature is. Oil should run about 200 degrees. Too cold and you don't vaporize the bad stuff, over 250 and it starts to break down.We can bat this oil question back and forth forever but no matter what oil you use if you do regular changes the chance of a failure related to the type of oil used is about nil.

 

[tommays]

Re: using automotive oil for a 4.3 stern drive

i like the back and forth it lets me here a lot of different opions and then use what i feel is the best one for my use<br /><br /><br />tommays

 

[garycinn]

Re: using automotive oil for a 4.3 stern drive

Originally posted by TheOilDoc:<br />When discussing diesels (Mercruiser does have diesel engines), CF-2 class oils are not excluded from being multigrade oils. They are not always two stroke single grade oils. The Mercury 25W-40 is an example of a multigrade CF-2.<br /><br />The newer CI-4 class does not make CF-2 oils obsolete, nor does it supercede CF-2. CF and CF-2 are current specifications with their own unique applications. CF has superceded CD and CE for diesels using fuels that contain high sulfur content. CF-2 has superceded CD-II where diesel ring and cylinder scuffing is a factor. CF-4 is another different classification. CI-4 oils do not necessarily meet the requirements of CF or CF-2. The CF classifications will be listed separately on the container.

That's why I like the Amsoil 15W40 diesel/marine oil -- one of the few that is recommended for CF-2 applications:<br /><br /> http://www.amsoil.com/products/ame.html

 

[WillyBWright]

Re: using automotive oil for a 4.3 stern drive

Uh Oh! Somebody used the "A" word. Now it'll Really get interesting, tommays!

 

[TheOilDoc]

Re: using automotive oil for a 4.3 stern drive

Originally posted by garycinn:<br /><br />That's why I like the Amsoil 15W40 diesel/marine oil -- one of the few that is recommended for CF-2 applications:

The "C" rating is a diesel rating. The Mercruisers being discussed are gasoline engines.<br /><br />Mercury specifically does not recommend using a synthetic oil or a 15W-40 viscosity oil. Be aware that some non-OEM oils are not licensed or certified by the API. <br /><br />According to Mercury:<br /><br />"IMPORTANT: The use of non-detergent oils, multi-viscosity oils (other than Quicksilver 25W-40 or a good quality 20W-40 or 20W-50), synthetic oils, low quality oils or oils that contain solid additives are specifically NOT recommended."

 

[garycinn]

Re: using automotive oil for a 4.3 stern drive

I wonder when the marketing at Mercury is going to let the folks in R&D know to update their recommendations now that Merc is selling their synthetic blend .

 

[garycinn]

Re: using automotive oil for a 4.3 stern drive

Mercury IS behind the times on their recommendations. Not only are they not recommending their own synthetic blend, but one of their "latest" recommendation is a category SH oil:<br /><br /> http://www.mercruiser.com/fueloil_recommendation_faqs#1124 <br /><br />According to API, SH is obsolete.<br /><br /> http://api-ep.api.org/filelibrary/Guidechart2002.pdf <br /><br />

 

[Scaaty]

Re: using automotive oil for a 4.3 stern drive

I'm going back to my electric trolling motor!!

 

[BillP]

Re: using automotive oil for a 4.3 stern drive

Originally posted by garycinn:<br /> Mercury IS behind the times on their recommendations. Not only are they not recommending their own synthetic blend, but one of their "latest" recommendation is a category SH oil:<br /><br /> http://www.mercruiser.com/fueloil_recommendation_faqs#1124 <br /><br />According to API, SH is obsolete.<br /><br /> http://api-ep.api.org/filelibrary/Guidechart2002.pdf <br /><br />

I'm definitely NOT a pro merc guy but where's the contradiction? Merc's web site only lists a 2 stroke synthetic blend oil. There isn't a 4 stroke synthetic crankcase oil listed. Is it missing from their web site?<br /><br />Maybe they are keeping the SH in spec until their stocks are depleted?

 

[Buttanic]

Re: using automotive oil for a 4.3 stern drive

For years Harley-Davidson did not recommend synthetic oils of any kind only their own brand of regular oil . Several years ago I got to visit Harley R&D at Talladega,AL. While touring their store room I noticed that the only oil on the shelves was Mobil 1, not a bottle of Harley brand oil in sight. When I asked why I was told it was for other vehicles, yea right than where was the Harley oil. He couldn't show me he said (top secret you know). Last year Harley came out with their brand of synthetic. I had been using synthetic for 15 years in my Harley with no problems. Several years before Harley came out with their synthetic one of their dealers admitted to me that he used Mobil 1 in his personal bike.

 

[seahorse5]

Re: using automotive oil for a 4.3 stern drive

The new Harley oil is a semi-synthetic blend and they call it Syn 3 because it is approved for the engine, the transmission, and the primary chain case.<br /><br />For years riders used Mobil 1 even though some folks said that synthetics were too slippery and the roller bearings would skid on the crankshaft and rod ends! <br /><br />Harley riders get as emotional about oil as boaters do!!!!! Check out some of their news groups.