Oil

[hannahbear]

I have a 3.0 Mercruiser and I'm changing the oil. The recommended oil is 25w 40 Quicksilver. I want to put in a synthetic oil because I heard it's better. I can't find a synthetic 25w 40. The closest I found was 20w 50. Would that be better than the regular oil (25w 40) since it's synthetic? Any thoughts or suggestions on weights brands or types would be appreciated......<br /><br />Thanks,

 

[hoot]

Re: Oil

i have run Mobile 1, 20W-50 for many years in a 250 cu in Merc in AL. Very happy with the oil. i also run this in my cars and lawn mower. Target stores sell this oil a little cheaper than Walmart. do a search on synthetic oils, should be a lot of info.

 

[charleswmoore]

Re: Oil

Amsoil is my choice. They make a Marine oil that has rust inhibitors also. I have ran this oil in my old Volvo 280 drive and it worked very well.<br />Also my wife runs in her car (Mine burns to much to jusyify) and engine wear in minimal. Quaker state now has a full synthetic but I have no long term experience with it to comment.

 

[marv plotzka]

Re: Oil

25w40 is Mercury’s proprietary way of saying good old API grade 30w. Mercursers don’t run hot enough to take advantage of synthetic oil. Your motor originates from a GM design. GM recommends against using 20w50 in any gas engine in their car and truck owner manuals. I use Valvoline Super HPO 30w in my Mercruser.

 

[jstamatov]

Re: Oil

Marv, if the 25w50 is just straight 30w, why does GM recommend against it? My OMC 4.3L manual recommends straight 30w oil, not the multigrade oils.

 

[marv plotzka]

Re: Oil

Jstamatov, please reread Hannahbear's and my comments, pay close attention to the numbers. You a few things turned around. If I was unclear, I can also try to restate my comment if that would help.

 

[dhammann]

Re: Oil

25-50 w is not straight wt 30, it is 25 wt oil with viscosity improver additives which will cause rings to stick. This is why GM will void your warranty for using it. Stick with straight 30 for your merc, it is what is recommended by the OEM, they know best. Synthetics are a waste of money in this application. In your auto multi-grade is fine but NEVER go above a 2 wt spread, for example 10-40. I speak from real world experiences not marketing.

 

[marv plotzka]

Re: Oil

“25w40”<br />I guess I need to take another shot at this. I spent a lot of time looking into this subject when I bought my Mercrusier. The wife and I saved 6 years to get this new boat. We cut every corner we could to save a buck. This thing cost 4 times what we paid for our pontoon boat and it was going to get the best of everything. Keep in mind, we were a one-paycheck family with young kids, and the pontoon was as basic as you could get, but new. That was my frame of mind. <br />I spent a lot of time trying research what 25w40 was. Only Merc. sold it. Couldn’t find it anyplace other than the dealer. Couldn’t even find any reference to it outside of the boat business. I work in the auto industry; you would think this would be easy info to find! I finally got a break one day while buying parts at a John Deere tractor dealer. I through out the 25w40 question. Timing is everything! Just so happened, there was an engineer from one of the oil manufactures looking at some wear problem on this huge piece of farm equipment. I asked the 25w40 question, she laughed, you’re the hundredth to ask that. I was told that, the criteria for testing and grading straight weight and multi viscosity oils differ from one another. Any high quality straight weight 30w oil will meet 25w40 requirements, and vice versa. It’s the same product, just good creative marketing. I use Valvoline 30w in my Mercruser, I can find it almost anywhere, and the price is OK to.<br /><br />“20w50”<br />This is a different can of worms! Of the GM owner manuals I have looked at, under “engine oil” section 6, there is a small note on the bottom of the temperature vs. viscosity chart and also in the text, “Do not use 20w-50 or any other grade oil not recommended” The guys around here that race, say not to use it in a production engine that has not had the oil passages reworked and a high volume / pressure oil pump and drive installed in it. One friend who dose repair work on the side, says he has seen oil pump shafts twisted and one broken from heavy viscosity oils such as 20w50. He also had some concern that the production oil pump may not be able to push the thick oil to the top end motor parts because of the low pressure they run at, like 60 psi or so. The racer types say they run the thicker oil because of the extreme high temperatures they run at and the oil the gets diluted from the rich fuel mixture they use.<br /><br />Take it all with a grain of salt, but personally I wound stick with 30w

 

[DJ]

Re: Oil

Marv,<br /><br />Great info.-Thanks!.<br /><br />It is also true that todays "automotive application" engines now reguire 5W-20. That scares alot of people. It is not necessary to be scared. The 5W-20 is SIMPLY a far superior product to the lubricants it replaces. Its viscosity rating is necessary for todays high (manufacure) tolerance engines-especially those with overhead cam systems and variable valve timing.<br /><br />I would not use it in a marine engine though-why?The people warranting these engines do not recommend it-yet.

 

[marv plotzka]

Re: Oil

Djohns19, I beleive 5w20 synthetic was listed for -20 degree F usage. Synthetics really shine in low temps. I am not at work, so I don't have the resouces I need to answer that. I remember that API "SL" is being used for that purpose. I snuck home early to get a head start on going to my cottage. I thought I would give mother nature one more chance to rain, sleat, hail, and snow on me. In short, I will look that up Monday, and post it than.

 

[DJ]

Re: Oil

Marv,<br /><br />I wasn't seaking of synthetic, just 5-20 in general. Appreciate anything else you have on the subject.<br /><br />Have a GREAT weekend!

 

[dhammann]

Re: Oil

On multi-grade oil the 1st number represents the base oil weight. The last number indicates a weight that the oil is equivalent to (flow characteristics) at a certain temperature. Multi-grade oil was created to assist in cold weather starting by using a lower weight ( less viscous ) oil that will allow the engine to spin over freely. These light oils contain additives that hopefully will make the oil perform at normal operating temperatures in the same way as the last weight listed on the range. <br />Boats almost always operate at optimal temperatures so there is no need to do this viscosity balancing act. The engineered clearances in you Merc are optimized for 30 wt oil when at operating temperature, period! Multi-grade oil is a compromise for a wide range of temperatures but does not guarantee optimal 30 wt protection at operating temp. Remember, 10w-30w is still 10weight oil! There are two types of lubrication in your engine, splash & hydraulic. “Splash lubrication” is oil being slung by the rotating parts in the engine, in this case oil weight is of little importance. “Hydraulic lubrication” is oil forced by the oil pump into the clearances of the crankshaft, rod and camshaft journals. This is where viscosity is important. The oil holds metal parts away from each other with oil pressure created from the pump. Lower viscosity means lower pressure. The lower the pressure, the less force it takes to push metal against metal. The deserving engineers that designed your engine have scientifically calculated clearances for a given oil weight and oil pump pressure. Most new automotive engines run 5wt oil, the reason for this was to increase federal mandated fuel mileage. These engines have been designed to safely run (and should) these light oils due to closer tolerances. These closer tolerances allow the thin oil to maintain adequate pressure in the journals. Your Merc is not designed this way.<br />Now, are you willing to let promotional hype or someone’s unfounded testimonial jeopardize the efforts that those engineers worked so hard to achieve? Oil manufactures work hard to make to a variety of oils for the engineers to design their engines to….it doesn’t work the other way around. If you play around with oils you are SWAGing which means taking “scientific wild ass guesses” Part of your hard earned purchased price paid for this design and engineering, abide by the OEM’s recommendations and life will be good.

 

[marv plotzka]

Re: Oil

Djohns19, this is what I can find for car and light truck: 5w-30 preferred for almost all GM gas engines. 10w-30, OK above freezing in most. Exceptions that I could find: (1) Corvette, synthetic meeting GM spec GM4718M. The engine oil fill cap reads “ Mobil 1” (2) Pontiac Vibe/Toyota Matrix adds 10w-40 to the 20w-50 “Do Not Use” list.<br /><br />Still, Big Dee is right, why would you want to use an oil type not recommended by your engine manufacture? There’s certainly plenty of high quality 30w’s to choose from.<br /><br />I think I will post an oil question for 4 stroke outboards, something I need to start gathering some info on before spring.

 

[DJ]

Re: Oil

Hi Marv,<br /><br />Ford went to 5-20 for '02' and up, except for diesel. <br /><br />I believe GM went to it for '03'. I'm sure there are some exceptiions, as you point out.<br /><br />Thanks.

 

[marv plotzka]

Re: Oil

Djohns19, the GM oil usage was from 2003. However I did find 5w20 motor oil at Wal Mart in the Motorcraft (Ford) brand, and at Meijers in Valvoline and Castrol brands. Meijers, the only store Wal Mart has been unable to wreck around here. As you can tell, I am not much of a fan of Wal Mart. The Valvoline oil was labeled for use in some Honda’s and Mazdas. I did get a little time free this afternoon to jump out to the “SAE” web site (Society of Automotive Engineers) and the “ISI Web of Science” web site. It would appear 5w20 is already being replaced by 0w20 as we speak. 5w30 & 5w20 are what is called an ILSAC GF-2 spec oil. They differ in viscosity modifiers, but 5w20 also has an “ organic molybdenum” friction modifier. This gains some fuel economy on engines that do not run “roller type” cam followers. I believe most US engines use roller type followers and that’s why 5w30 is still being used, at least for now. 0w20 may just change that. 0w20 is an ILSAC GF-3 spec oil, so to say, the next generation oil. GF-3 oils are required to improve fuel economy and for a longer period of time than GF-2 oils. 0w20 also uses a similar “ organic molybdenum” friction modifier, but different base stock oil. It improves fuel economy even on “roller type follower” engines. Claims are 1 to 2%. Nissan Motor Co. has a good down to earth technical paper written on 0w20 oil, SAE web site, doc. #2002-01-1636. Good reading, but more info than I really need! In general, the new oil is a cost effective way of gaining fuel economy, compared to engine redesign. It will be interesting to watch in any case. Oh yes, Chevron has a good web site to.

 

[Oil Man]

Re: Oil

You hit the nail on the head with the fuel economy info. The 5W-20 oil is NOT a superior oil. It was introduced solely to reduce Corporate Average Fuel Economy (CAFE) numbers. Honda and Ford have both reduced their engine life expectancy by more than 30% when using the 5W-20 oil.<br /><br />Dave

 

[mkast]

Re: Oil

As I remember from aircraft school, when oil is used for lubrication and cooling and cleaning, film strengh, the lightest FILM on the bearing (journal) that will lub, cool and clean is the most desirable, without breaking down. New (2002) car emgines are built to use this grade (weight) 5W 20 of oil. Use straight grade 30 oil in your boat, good oil not whats on sale at the gas station. $2000 to $8000 emgine, let's save 50cents a quart! Premium filter no Frams, cardboard ceck valve. We're all going to hear about "I use this... and never had a problem" great, I've been making a very good secondary income, tearing down marine engines for the past tirty years, all you boaters out there, keep up the good work!