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Results 1 to 15 of 15
  1. #1
    Join Date
    Mar 2012
    Location
    Clemson, SC
    Posts
    110

    Default Best oil for mercruiser 470?

    hey guys im about to do an oil change and was wondering what you guys usually use? I have been reading around and it seems that 25w40 is the way to go. Should I use synthetic or conventional, and how many quarts should I use? Thanks!

  2. #2
    Join Date
    Dec 2008
    Location
    Buffalo, NY
    Posts
    78

    Default Re: Best oil for mercruiser 470?

    These are "flat tappet" engines. While the lifters are still hydraulic and not solid like some older high performance auto engine these cams and lifters like an additive called ZDDP to keep these flat tappets from wiping a cam. Modern engine oils now have been forced by the government to reduce levels of ZDDP in their oils. Not bad for newer engines but bad for older engines with flat tappet cams and lifters. However diesel oils still have a higher and acceptable level of ZDDP in their additive packages. The key is a "CJ-4" rated diesel oil. Shell Rotella is such an oil. You will find it most everywhere in the weight you choose to run. Me I will run Shell Rotella 10w-30 with a Baldwin filter in my 470 this summer. I'm in New York and my operating air and water temps will not be extremely high.

    Dennis

  3. #3
    Join Date
    Mar 2012
    Location
    Clemson, SC
    Posts
    110

    Default Re: Best oil for mercruiser 470?

    thanks! Do you think the 25w40 would be better for me since it is warmer here or do you honestly think i should go for 10w30 by rotella?

  4. #4
    Join Date
    Sep 2010
    Location
    Jersey Shore
    Posts
    3,197

    Default Re: Best oil for mercruiser 470?

    Quick silver 25w40 is what you should be using in that engine.
    Chris
    Dockside Marine Services
    Jersey Shore.
    Let the insanity begin.

  5. #5
    Join Date
    Dec 2008
    Location
    Buffalo, NY
    Posts
    78

    Default Re: Best oil for mercruiser 470?

    I don't know exactly where you are. My water temps will be in the 40's early and the 70's later in August/September so my engine operating temp will be on the lower end toward 160*. My air temps will rarely get out of the 80's. So I will stay on the lower or thinner side. If you are in hotter conditions I don't think a higher and heavier oil would be a bad thing. Key to me is whatever you use keep a good filter on it and keep the oil fresh based on how many hours you feel you have run on your fresh oil.

  6. #6
    Join Date
    Dec 2008
    Location
    Buffalo, NY
    Posts
    78

    Default Re: Best oil for mercruiser 470?

    Quote Originally Posted by Docksidemarineservices View Post
    Quick silver 25w40 is what you should be using in that engine.
    I'm a little confused here so straighten me out. I have the original "Operation and Maintenance Manual" Model 470. It recommends SAE 20W SE for operating air temps 0*F-32*F, SAE 30W SE for temps 32*F-90*F and SAE 40W SE for temps over 90*F. Has this changed over the years? Was there a tech bulletin?

    Dennis

  7. #7
    Join Date
    Jul 2008
    Location
    Northboro, Ma, USA
    Posts
    3,486

    Default Re: Best oil for mercruiser 470?

    The use of mercury 25w 40w is about all that is reccommended or needed if no preference is stated........period.

    No need to look at a almost 40 year old oil spec. Oil has come a long way since then.

    If you really want to do it right simply use mobile 1 15w-50w full synthetic and be done with it once and for all.......

    for years the older stuff had straight weight reccomendations. But I bet to keep it simple and the lack of a special need (unless you live near the nort/south poles) a multigrade is all that you need. (of course this is for a pleasure boat and not some high power high horsepower motor.)

    Also when was the last time anyone can remember hearing that motor oil cause a failure of any type buy using any wieght not reccomended by the OEM?

    Nuff said

  8. #8
    Join Date
    Dec 2008
    Location
    Buffalo, NY
    Posts
    78

    Default Re: Best oil for mercruiser 470?

    Quote Originally Posted by kghost View Post
    The use of mercury 25w 40w is about all that is reccommended or needed if no preference is stated........period.

    No need to look at a almost 40 year old oil spec. Oil has come a long way since then.

    If you really want to do it right simply use mobile 1 15w-50w full synthetic and be done with it once and for all.......

    for years the older stuff had straight weight reccomendations. But I bet to keep it simple and the lack of a special need (unless you live near the nort/south poles) a multigrade is all that you need. (of course this is for a pleasure boat and not some high power high horsepower motor.)

    Also when was the last time anyone can remember hearing that motor oil cause a failure of any type buy using any wieght not reccomended by the OEM?

    Nuff said
    I know my information is old information and our new oils are very good. Thanks for your input.

    Dennis

  9. #9

    Default Re: Best oil for mercruiser 470?

    I originally mentioned about the ZDP (I mean ZDDP) My mistake but it has been awhile since I read on this matter and I guess I was pretty close Dennis. Anyway, my belief is that 10w30 covers a wider range of operating environments. Their were heated debates on the issue of what type of oil to use. my engine oil pressure at startup is pushing around 75-80 psi which to tell you the truth is pretty high but after warmup it drops to like 55-60 and when I run hard for a period of time on a so called 90 degree day and bring the engine back down to idle, you could probably expect to see it drop down to 15-20 or even less depending on how old the engine is with respect to condition of the rings. You don't want to much blow-by if the engine is tired so maybe 10w30 is not the right choice. Also, could cause seals and or pan gasket to leak if too much oil pressure also. Just something to think about. At the same time you want to protect all the internals and keep the oil as cool as possible. I have an oil cooler on my 1988 3.7lx four barrel and it seems to help. I also let my engine reach operating temperature in the hopes of thinning the 10w30 a bit especially if your running in colder weather. Make sense to you guys? That is why I would never recommend types of oil to anyone. What dockside marine and kghost said is probably correct as per manual and he probably knows from lots of experience with the 470's I am sure! lol That is why I recommend keeping your oil spotless along with filter etc. Call me anal but before I take my boat out, I look at the dipstick and if it don't look like Aunt Jemima syrup then I change it just to be safe. In other words, if it looks black, I change it. (no exceptions). But it all costs $$$$$ lmao! Finally, make sure your oil sending unit, and coolant temp. gauge are all working properly and keep your eyes glued to the darn things as much as possible when running high rpms. jmho. I have a high temp. buzzer on my cooling system that goes off if the engine reaches over 200 degrees. It has never gone off yet and I pray it never does! lol said enough, later Tom
    Last edited by 1973 Browning Marine; 03-28-2012 at 01:30 PM.

  10. #10
    Join Date
    Dec 2008
    Location
    Buffalo, NY
    Posts
    78

    Default Re: Best oil for mercruiser 470?

    I'm as anal about oil and filters in everything I own and this 470 will be no different. I'll watch my start up oil pressure and operating oil pressure and adjust from there.

    jadilla- Most oil threads such as this will get many responses. Use good oil and filters and keep them clean. All should be good. Hope this has helped you.

    Dennis

  11. #11
    Join Date
    Jul 2008
    Location
    Northboro, Ma, USA
    Posts
    3,486

    Default Re: Best oil for mercruiser 470?

    I participate on a few other websites, NON BOATING.

    There are indepth oil topics.

    For marine use a higher viscosety is desired due to higher RPM usage. That is it!
    If you do some reaserch a lot of race motors use I believe 50 weight racing oil.......sustained high rpm usage.


    So for a pleasure boat that will not exceed 5000 rpms in reality almost any standard oil will work. The reccommendation of 25w-40w is because that is what Merc sells. That is what a marine business will use (certified merc that is).

    if one wanted to use 10w-40w, so be it it will work and it will work just fine.

    The only time I would expect to see an oil leak due to oil types is when you go to synthetic on a older engine. this oil is much "slicker" than conventional dino oil and will leak at the rear main and possibly other areas as well. But going from 30 wieght to a 20 or even a 15 wieght of the same base oil type should not show leaks due to lower viscosety.

    Oils main purpase is to form oil layer between parts (crank & cam bearings, lifters/cam, push rod to rocker arm, oil pump gears, distributor gear).
    Also one of the most important functions is to remove heat.

    Typically running a thin viscosety oil allows it to travel fairly fast throughout the motor. This incease in speed reduces the amount of heat it can remove over a given amount of time. A heavier viscoaety oil will move slower therefore take with it more heat.

    I have witnessed this on a race engine dyno session using several types of oil to see if one would increase power vs the other. Mostly the lower viscosety oil caused slightly elevated temps vs the other.

    Bottom line is use what you like. Try to keep near OEM specification and all will be just fine!!

    Of course using OEM oil is the preffered reccomendation to those who want to use what is reccommended...........
    Last edited by kghost; 03-28-2012 at 02:04 PM.

  12. #12
    Join Date
    Jul 2007
    Location
    Lake Ozark, MO, USA
    Posts
    67

    Default Re: Best oil for mercruiser 470?

    Hello,
    I would also throw in the suggestion of using an anti-drain back filter, over time this decision could be important to engine wear on start up.
    Do watch the low oil pressure when coming to idle from running at cruise/hot, it will be uncomfortably low on these engines. Might try and plan to be able to run 1000 rpm+ for a bit, as the engine cools the pressure will come back up at proper in-gear idle. Agree with Tom, starting pressure is also uncomfortably high, let them warm up a bit.
    Just for trivia, ZDDP (zinc) was removed from oil as it hurts the life of catalytic converters. If you want it you can get the additive alone and oil with it still in it.
    Wouldn't recommend over 25-50 hours between changes on this engine on regular oil, you could go longer on synthetic as it doesn't have base impurites that make oil start to break down. Depending on your use it can be tough to put that many hours on in a season. if you don't have one get a battery powered oil extractor, worth its weight in gold. You can punch a hole in the filter and suck the oil out with it as well so it doesn't make such a mess in the bilge.
    Mark

  13. #13

    Default Re: Best oil for mercruiser 470?

    Thanks kghost for the input. I failed to mention that I use a sythetic 10w30. My bad. It never fails to surprise me how much you can learn on this site if you are willing to listen and I for one am sucking it all up like a sponge! lol (good information) I've tried my best to help these other guys that own these 470's so they might have a chance at having some fun on the water this season. It's a pain in the ass but these little engines run ok if you are persistent about maintenance and the owner doesn't abuse the engine. When I first started building my engine, I was thinking of how fast I could go. lol Now I am happy cruising all day at around 30 mph at around 36-3800rpms. That's plenty fast for me and a little easier on the engine instead of running full out and beating the living puss out of the poor thing! lol It sure as heck aint no racing engine but has plenty of torque and moves the boat nicely through the water. Thanks also mark_searay for your comment. I never thought of keeping the rpms at around 1000 after a hard run. Nice! Good idea on a real hot day after running hard all day. Makes sense! I will try that and see what my oil pressure does. Thanks again guys, Tom

  14. #14
    Join Date
    Mar 2012
    Location
    Clemson, SC
    Posts
    110

    Default Re: Best oil for mercruiser 470?

    Thanks for all the help guys! I think I'm going to go with 25w40... it gets a little hotter in upstate SC.

  15. #15
    Join Date
    Jul 2007
    Location
    Lake Ozark, MO, USA
    Posts
    67

    Default Re: Best oil for mercruiser 470?

    To get a post run cool-down to get idle oil pressure back up, it doesn't take much, 2-5 mins for me in heat of summer. That is not much time when you are coming into a dock or cove etc... Just off idle for a bit may work for you if you run in cooler water. Just try a few runs see how she responds. Once you lose just a bit of cruise level heat the pressure stays better at idle-hot. Surface water temps where I'm at are high 80's in July & August with air temps hitting 90-100+, colder water temps will help of course. I also run the twin bilge blowers all the time except at night at cruise speeds. Exchangers are 4" and radiator shop clean. It's just hot in that bilge no matter what.

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