what kind of oil?

[cntrydude]

Oh boy, here we go!

 

[cosander]

what kind of oil?

I have no mercruiser shop near by. Is there a good oil I can find at autozone for my 170 mercruiser?

 

[Haut Medoc]

Re: what kind of oil?

I'msure you'll get a zillion answers, but any straight 30 weight should do......J

 

[LubeDude]

Re: what kind of oil?

Originally posted by cosander:<br /> I have no mercruiser shop near by. Is there a good oil I can find at autozone for my 170 mercruiser?

Well, you are pretty new here, so I wont be hard on ya by saying some smart remark, Like, You had to do it didnt ya? <br /><br />We just did this a short time ago, and here is one link.<br /><br /> Oil thread <br /><br />If this isnt enough, do a search in the search function on oil.

 

[cosander]

Re: what kind of oil?

So I will be ok if I put 10w30 in it? Also what makes the high mileage oils (75,000+) special? Would it help to use this in a high houred boat. thanks for the help

 

[vipzach]

Re: what kind of oil?

You should be fine with 10w30. I would use straight 30. High mileage oils are supposed to soften up seals and things to help keep them good and other goodies like that. I don't know if they really help or not. It looks like you are in Dallas area (dfw) you will be fine with straight 30.<br />Watch out this thread could get long and ugly!

 

[LubeDude]

Re: what kind of oil?

As you can see, oil related question soon get out of hand at times.<br /><br />Do you have an owners manual? If so, what does it say to use.<br /><br />It boils down to how you use your boat. Im sure that your owners manual would likely tell you to use a straight 30W, or a straight 40W. Depending on your climate for around 100 Hrs between changes. If you run WOT most of the time you should change more often, say about 50 hrs. Boats generally will have fuel delution issues, so extended drain intervals are not generally a good idea.<br /><br />As to your question about using a 10W-30, if it has a C4 rating it will be fine for general use, but if you are running hard most of the time, use a straight wieght.

 

[jeff13601]

Re: what kind of oil?

I put 5w30 in mine. Is that ok?

 

[jeff13601]

Re: what kind of oil?

And how long do I have to be a seaman apprentice?

 

[vipzach]

Re: what kind of oil?

This is gonna get out of hand.....5w30 starts pretty thin, but may be ok since NY is pretty cool, but in the summer I would use 10w30 or straight 30

 

[LubeDude]

Re: what kind of oil?

Originally posted by jeff13601:<br /> I put 5w30 in mine. Is that ok?

If its not a synthetic, I would say "no", unless you boat regularly boat in the Antarctic. A synthetic will not have the Viscosity improvers that the regular dino oil will have.

 

[tommays]

Re: what kind of oil?

guessing your from dallas fort worth <br /><br />with the summer temps there ST 40 would be on the thin side on those 100 deg days<br /><br />tommays

 

[cc lancer]

Re: what kind of oil?

My Mercruiser dealer says only use Mercruiser 25-40 weight oil in my engine.<br /><br />CC lancer says: Why can't I use 15-40 Mobil, or Pennsoil, or Castrol.<br /><br />My Mercruiser dealer says my oil is better.<br /><br />CC Lancer says: Where is the refinery?<br /><br />My Mercruiser dealer says I don't know.<br /><br />So with this bit of wisdom you decide what kind of oil to use.

 

[LubeDude]

Re: what kind of oil?

Originally posted by cc lancer:<br /> My Mercruiser dealer says only use Mercruiser 25-40 weight oil in my engine.<br /><br /> Because I sell it! <br /><br />CC lancer says: Why can't I use 15-40 Mobil, or Pennsoil, or Castrol.<br /><br />My Mercruiser dealer says my oil is better.<br /><br /> Because I sell it! <br /><br />CC Lancer says: Where is the refinery?<br /><br />My Mercruiser dealer says I don't know.<br /><br /> But because I sell it My oil is better! <br /><br />So with this bit of wisdom you decide what kind of oil to use.

 

[Scaaty]

Re: what kind of oil?

Originally posted by vipzach:<br /> This is gonna get out of hand.....5w30 starts pretty thin,

A 5w is, and always will be, a 5w. When/if the viscosity improvers and polymer chains break down you are back to 5w. I use 15-40 diesel oil, because I do not run a lot of high speed stuff, mostly 2000/2500, on plane (5000# 350SBC)only 3300. Book calls for ST40, but hey, its an oil question!

 

[Boatist]

Re: what kind of oil?

Cosander<br />Most manufacturers will say use a straight 30. Check your owners manual. I ask at least 4 difference groups of factory reps at boat shows and each said the same thing. "We do not recommend 10-30 or any multi viscosity oils" I ask why not and they all said. "The viscosity modifier is not oil and it breaks down faster than the oil so use a straight weight." I said but we all use 10-30 in cars. They all said, "How offten do you run your car at full throttle for a long period like many boats do."<br /><br />Auto manufacturers also do not recommend 10-40, They say causes rings to stick. Howerever they do recommend 10-30. Some say it is because 10-30 help them meet the fleet fuel mileage requirment.<br /><br />The Synthetic crowd will all say use our oil as it is better. Synthetics may be better but I have never seen a straight 30 weight like most mauufacturers specify. I belive Mercury 25-40 is a Synthetic oil and it has a very low viscosity index but is high cost. <br /><br />I use a Quality Straight 30 as my owners manual specifies, but I some time use one quart of Synthetic. This is because of a Popular Mechanic's artical I read years ago where they were testing oils including Synthetics. In the end of the artical they said useing one quart of Synthetic mixed with the other oil would give you 80 percent of the bennifit of synthetic without the high cost.<br /><br />Bottom line is use what your owners manual says if it is under warranty. If not then use what you think is best. You will find no clear answer here or on any other board.<br /><br />If I was going to use a multiViscosity oil I wouldd go full Syntheitc. I also feel there very few oil related breakdowns unless they are running water with the oil.

 

[lakelivin]

Re: what kind of oil?

Boatist:<br /><br />From previous posts here Iv'e learned that Merc's 25-40 is NOT synthetic, it's a unique blend of 25w & 40w oils without the multiviscosity polymers that could lower the viscosity if they break down under high loads.<br /><br />Merc did just come out with a partial synthetic 25-40 oil last fall, but alot of shops haven't even heard of it, let alone stock it. <br /><br />As for the rest, I say look through the previous oil posts & make your own conclusion based on the facts/ opinions offered. There is quite a bit of educational information that's already been posted.

 

[TheOilDoc]

Re: what kind of oil?

HERE is a list of the NMMA's FC-W oils approved for marine use.<br /><br />As for straight-weight marine synthetics, there are SAE 30 and SAE 40 PAO oils available from oil makers like Royal Purple as seen HERE<br /><br />I would not recommend a multi-viscosity 10W-30 or 5W-30 automotive oil. A marine grade SAE 30 oil will provide better protection, and that's probably what's recommended by the manufacturer.