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Changing oil-Is this guy playing with fire"

N

nightstalker

Regular Contributor
Talking to a guy at my marina a couple of days ago who told me that he was "thinking" of changing his oil this year (twin 1992, FWC, 454 Crusaders). I said thinking? He said that he puts less than 10 hours a year on his engines and figures that the oil can't get very dirty in that time. He told me that he changes it every three years or so. He said that it looks clean. Now, far be it from me to tell anyone what to do with their Crusaders based on my very limited knowledge, but I think this is asking for trouble. I figure that you can't really tell how clean your oil is just by looking at it without having a sample of it tested. Also, an oil change with filters, etc. is a pretty simple, inexpensive part of regular maintanence right? Doesn't oil with limited hours on it still build up that toxic stuff that shouldn't be left in the block during winter storage?
Nightstalker
 
Doesn't oil have a shelf life? If you poke around, some folks say that unopened oil is good for at least two years, some say you should shake old oil, some have witnessed "slugs" developing in 10 year old oil UNOPENED at the bottom of the bottle. In the oil pan, exposed to temperature extremes, and with lots of surface area exposed to absorbing moisture, and evaporating volatiles, bad things would happen faster. And, is this synthetic or mineral based oil? I'm not as worried about the 10 hours of use as the instability of the oil itself.
 
Rule of thumb. If the guy at your marina is not a Working or retired Marine Mechanic, you can listen to his advice and ask a professional first.

The reason you change your oil after 50 hours is dirt and viscosity breakdown.

You change it at the end of the season no matter how few hours you used the boat, because used engine oil is caustic.

Caustic: Capable of burning, corroding, dissolving, or eating away by chemical action.
 
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Engine oil with only 10 hours on it may not pose an issue. I suppose that it could be tested if he's up to the task and expense of it.
But I'm with you..... why not just change it????

Oil becomes contaminated with not only the metallic wear residue, but with alkalinity and acidity from combustion biproducts as well.
Our oil filtration should take care of the wear particles, but according to the experts, the issue is with alkalinity and acidity when leaving it installed for the lay up duration.

I've left 5 to 10 hour oil in for the winter before, but I doubt that I'd leave 20 or 30 hour oil.
 
It's the acid component that wreaks the havoc. and what does 10 hours mean....if 9 1/2 of them were idling...enough said. No reason Not to change it.
 
I would change the oil even if it only had 5 hours on it. I believe that oil begins to lose it's "V" after sitting for a year or so. Also, any acid that builds up, no matter how little can't be good. Plus, the cost of changing oil, filters, etc. equates to an eighth of a tank of fuel in my vessel, and I can burn that much fuel in two hours of running.
Nightstalker
 
I seem to remember the Crusader manual stated 100 hours for a oil change. Which works out to a season for me.
 
That guy is a moron! Check this out:

Since I maintain a fleet of street vehicles, and I didn't want to bother with recording mileage on all of them, I came up with an alternate plan years ago: I change the oil in all of my cars Spring and Fall. Period. On the wife's car that's at least 10,000 miles; on mine, 500 tops; and on my kit cars, maybe 500 YARDS. (That's right, yards.) Guess which oil is the dirtiest?

Jeff

Answer: All of them are the same.
 
Right! Going THREE years without an oil change--in ANY vehicle--is a really dumb move; and in a marine enironment, it's just plain stupid!

Jeff
 
You can't fix stupid! For the price of oil and filters, I would change my oil every season even if I only put 1 hour on the engines.
 
This reminds me of the old days in the 1950's when I saw my Uncle's garage. Back in those days very few had money so he had old car oil in glass jars. He would let them sit and the contaminates would sink to the bottom then he would skim off the oil and reuse it in his car. He did that for 20 years and never had an engine problem.
Just thought I would tell this story.
 
I've seen that done, and it works just fine. In fact, you used to be able to buy "recycled" engine oil (for oil-burning cars). It was much cheaper than new stuff and worked just fine. They put new additives in it.

That crud at the bottom of those glass jars is WHY you need an oil change!

Jeff
 
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