[C320-list] Mixing Oil Brands

[Bruce Hunter]

I changed the oil and filter yesterday with Shell Rotella 15W-30 and a factory filter, all went well but I noticed an increase in idle rpms. I wouldn't have thought it made a differance but the only thing I can think of is that the old oil was straight 30 or it was very dirty. I'll adjust the idle speed this week.



From: resloat <resloat at comcast.net>
To: C320-List at Catalina320.com 
Sent: Saturday, November 3, 2012 3:46 PM
Subject: Re: [C320-list] Mixing Oil Brands

Bruce-As long as you use a trusted brand of oil for a marine diesel there should be no problem with draining warm engine oil through the dip stick to get as much as possible out.  Then add your Rotella to the proper fill level.  I don't think any marina asks the skipper what brand of oil was in the engine if they do an oil change for the owner.  They don't worry about oil compatibility issues with so little of the old oil left.  Spend time getting the last bit of old oil out and if the engine oil is warm and there should not be a lot of old oil left.  I find that if I get the engine oil warmed up and use a vacuum drainage system the the total oil from the engine and from the filter is essentially what the 3GM30F requires (2.6 liters in the pan = 2.7 quarts + a little from the oil filter)  I generally use a little over 3 quarts for a complete refill with filter change.

I have the Yanmar factory service manual.  It spends 7 pages on fuel and lubricating oils.  Shell Rotella is one mentioned as recommended.  Most of the others mentioned are brands I have not seen so I assume there are many other lubricating oils with the same SAE classification as Rotella that are OK.

Maybe the former owner had a log of maintenance and indicated oil changes and what oil was used.  I keep one for all maintenance I do.  It is a good practice and demonstrates care for the vessel.  It might even help at resale time when the much larger boat purchase is allowed by my lovely spouse.

Bob Sloat
Savannah Hull 894 (2002)
----- Original Message ----- From: "Bruce Hunter" <swampcreek42 at yahoo.com>
To: <C320-List at Catalina320.com>
Sent: Friday, November 02, 2012 3:34 PM
Subject: [C320-list] Mixing Oil Brands


We just bought a 2000 Catalina (Hull 719) in Seprember. Sadly the time has wizzed by and we'll be pulling her for dry storage on November 16th. Tomorrow we will be bringing her down from Baltimore where we hid her from the storm (Protected floating docks are GREAT!) and the engine will be nice and hot. I want to change the oil but I don't know what the previous owner used. I am planning on using Shell Rottella 15W-40 since I use it in my truck diesel and I've read it works well in the 3GM30F as well. I know I won't be able to get all the old oil out and some will be left in the pan, I'm thinking I will change it tomorrow and then once more before pulling it to lessen any reaction of different oil brand chemical packages negatively reacting with one another. Any thoughts?

Bruce
Hull #719