Harder to find

[PJ]

I own a H34 with a Yanmar 3GM. In the spring after relocating to my slip, I always change oil & filter & fill with 40 wt. Castrol. In fall before pulling I again change oil & filter & replace with a 20 wt. Castrol. I feel the winter oil acts as a cleaning agent to help remove all old summer oil & its contaminates during winter layup & with the spring change it insures almost a total old oil removal. It may be overkill but oil & filters are cheap. This year in spring I could not find any Castrol or Penzoil with a CD or similar deisel rating, so I stopped at the local marina & used a Shell brand called Rotilla that indicated it was formulated for deisels with various military & automotive designations. In the fall when changing the summer oil out it seemed the summer oil was much more dirtyier than previous oil changes. Is the Shell product suitable? Any explanation for the seemingly excessively dirty oil.Thanks for your help.P.J.

 

[Gordon Torresen]

Oil changes

I believe the reason that it is getting harder to find and oil with the CD rating is because yhe classification has been phased out. Today's ratings for diesel use are CH-4, CG-4, CF-4 among others. You will find these API specifications on both regular and synthetic oils. I have chosen the Quaker State brand to be used at our marina because of its ubiquitousness. I don't believe in changing oil brands and recommend to the some 200 owners for whom we change oil that if topping up is required, that they stay with Quaker State. It is available at most any marina, auto parts store or discount house like Wal-Mart. All the oils are made to suit the API specs for lubricity and many other things. The additives put in by the formulator are generally proprietary. It is a reaction between additives that can be avoided by not changing brands. As for the new oil looking dirtier than the old, it could be because it cleaned better.

 

[Jim Russell]

Gordon - question for you

PJ is changing in the fall which makes sense to me to elimiante the impurities, water, etc., that has formed in the oil over the summer which could corrode and otherwise affect the engine adversely.However, is there any real advantage in changing the oil again in the spring? I'm in a dry climate so what I do may not apply to an ocean dry dock, or an in water over wintering.Could you give us some pros and cons on that.Thanks

 

[Gene Barton s/v Paradigm]

Spring Oil Alternative

Jim, I change the oil in the fall, but leave it about a half quart low. My theory is that over the winter, any oil in the engine will all find its way to the bottom, and so in the spring you are starting with a "dry" engine. The first time I start the engine in the spring, I add the missing half quart and wait a minute or two for the new oil to seep through the engine. Then when I start it, there's some new oil already on the moving parts. Now, this might all just be wishful thinking and maybe not worth the trouble, but I figure it does no harm and may do some good.

 

[Gordon Torresen]

Response to Jim Russel

Changing the oil without running the engine doesn't make much sense to me either. However, I will never try to dissuade anyone from changing oil. We generally change oil in the fall, if it needs it or not. A running time meter would probably be a better indicator. It could tell you to change the oil twice in one season or every other season. Some owners don't put 20 hours on in a year while others are fortunate enough to put on several hundred.