3.0L Break-in question

kozman01

Petty Officer 1st Class
Joined
Jul 28, 2003
Messages
242
Does the new 3.0 liter MerCruiser engines come filled with the 25W-40 synthetic blend oil that is sold on the shelves? The reason I ask and hear me out on this, is that it is well known in the motorcycle community that the pieces in the engine are not perfect and when you first run that brand new engine, those ill-fitted internal pieces will be sheared off and placed into the oil. Now of course, the transmission on the motorcycle engine is using the same oil, so many new metal components are being sheared off in there as well. On a brand new bike engine, I change the oil/filter at 20 miles and at 200 miles. My oil analysis shows that after the initial 20 mile change, there is virtually no metal residue. I don't like to follow the manufactures advice on changing the oil at 600 miles and having all that lovely metal running around in the system. During the first 1500 to 2000 miles on my bike motors, I run conventional oil so everything can seat well, then I switch over to a full synthetic, especially on the air/oil cooled bikes.(Shell Rotella Synthetic 5w-40) Now, I'm not looking for the typical oil war to break out here, I'm wanting to know, should I apply my thinking about bike motors to this 3.0 MerCruiser AND if I should, does the motor come from the factory with the Mercury semi-synthetic(25w-40) or a conventional oil? If it comes with the conventional oil, I will of course need to replace w/ conventional oil until the appropriate time to switch over to the semi-synth. or whatever I decide to go with. Any advice is as always greatly appreciated!!
 

tommays

Admiral
Joined
Jul 4, 2004
Messages
6,768
Re: 3.0L Break-in question

the most inportant thing is to leave in the orginal oil for the FULL BREAK IN TIME after that you will get nothing but different points of view on what is best<br /><br /><br />tommays
 

jeff13601

Chief Petty Officer
Joined
Apr 30, 2005
Messages
593
Re: 3.0L Break-in question

I believe that you should go with what your warranty requests. If you want to change the oil a little sooner I am sure that would be fine but use the oil that your warranty calls for.
 

kozman01

Petty Officer 1st Class
Joined
Jul 28, 2003
Messages
242
Re: 3.0L Break-in question

What I'm looking for is what the original oil is. If it's the semi-synth. Mercury 25w-40, ok, I'll put that in, if it's some other conventional Mercury oil, I'll put that in. I guess all I really need to know is what Mercury puts in the engine at the factory. Thanks again gentlemen! Mercury can't get me on a warranty claim for changing the oil out too early, AS long as it's the same oil in the crankcase from the factory. :) I had a Suzuki tech that was doing some work on my bike and said changing the oil out the first few miles of the bikes life is the best 20 bucks ever spent. I figure I can't go wrong for 20 bucks.
 

tommays

Admiral
Joined
Jul 4, 2004
Messages
6,768
Re: 3.0L Break-in question

normaly the break in oil is different in a way i am not qualfied to say<br /><br />but you dealing with old style american iron that needs a real break in time<br /><br />wonder oil will not allow this to happen its to slippery<br /><br /><br />tommays
 

kozman01

Petty Officer 1st Class
Joined
Jul 28, 2003
Messages
242
Re: 3.0L Break-in question

True. I'm very aware of that and that's why I want to make sure the same oil goes in. On my big 1200cc hotter than hell running Suzuki engines, after that initial 20 miles, good old conventional Kendall GT1 goes in the crankcase and that is ran until approximately 2K is on the odometer. Does Mercury make a straight conventional oil?
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 3.0L Break-in question

Mercruiser does not use the synthetic 25w-40 oil in it's engines. It was developed for the Verado outboard by Mercury Marine, but the synthetic is not put in any Mercruisers from the factory.<br /><br />
Merc%20Oil%20Recomendations.jpg
 
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