Checking the Oil Level

[sailorboy1]

I bet the oil change interval changes depending of the distance one travels each year. I did lots of research before deciding it was fine to go to the 300 hours, way more than crowd source internet forums.

I think changing the oil is up there with replacing your seawater impeller every year. Some just like that feeling of "doing something".

[Lepke]

Synthetic oil get just as dirty, just as fast as petroleum oil. It's the debris held within the oil that causes engine parts to wear. If you want to extend oil changes you need to explore better oil filtering systems or except that your engine will wear out early. Testing your oil will tell not only the debris load, but what parts are wearing too fast. I test my oil once a year and centrifuge the oil.

[Cadence]

Originally Posted by Lepke

Synthetic oil get just as dirty, just as fast as petroleum oil. It's the debris held within the oil that causes engine parts to wear. If you want to extend oil changes you need to explore better oil filtering systems or except that your engine will wear out early. Testing your oil will tell not only the debris load, but what parts are wearing too fast. I test my oil once a year and centrifuge the oil.

I doubt many actually run the oil till it breaks down but it loads up with carbon an metal fragments. So extending changes may not be smart no matter what you pay for it per gal..

[a64pilot]

Pretty sure particles smaller than 2microns cause very little wear.
I think a normal oil filter filters down to about 20 microns, however a high bypass filter can go down to 2.
In theory if you filter the oil fine enough then you don’t need to change it until the total acid number and total base number cross, meaning the oil can’t neutralize all of the acid anymore, although you ought to be able to boost the TBN with an additive I guess.
Just little motors like ours the payback isn’t there, cheaper to just change the oil, but if your oil capacity is measured in gallons instead of qts, then it starts making sense.
That is why I believe that high bypass filtration never caught on.

About the same time as high bypass filtration, pre-lubing also became popular, the theory at the time was if you pre-lubed before start, your engine would last nearly forever.

[sailorboy1]

Filter seems a waste of time in a way. Right in my engine manual it's change oil every 150 hours, but change oil filter every 300 hours.

[a64pilot]

The stock filters are more rock catchers than anything. They do catch a lot of carbon that comes off of the bottom of the Pistons etc, so they do do something. At 150 hours, its not full of rocks, it’s likely not full even at 300, but best to change before it bypasses.
Most of us change filters at each change to not leave that bit of dirty oil in there.
Just for comparison an aircraft with an oil filter change interval is 50 hours. No filter, just a screen, 25 hours.
Neither is due to oil breaking down, it’s mostly due to accumulated lead and sludge, oil gets dirty, You change it.

[SV Bacchus]

Originally Posted by sailorboy1

Filter seems a waste of time in a way. Right in my engine manual it's change oil every 150 hours, but change oil filter every 300 hours.

My Diesel genset gets run a lot more frequently, daily in fact, than my Yammie boat motors. One time I decided to skip the filter change, I thought about going to every other time. Almost immediately, probably within a day, I had "oil filter" remorse. I said to myself "You cheap bast$$rd, how much money did you save and was it really worth it?"

One thing I admired about you SB1 is that you live and let live. You don't care what other people do, you do your own thing and you don't give a rat's butt about what they think about what you are doing! Good on ya!

[sailorboy1]

[QUOTE=SV Bacchus;2688743 You don't care what other people do, you do your own thing and you don't give a rat's butt about what they think about what you are doing! Good on ya![/QUOTE]

not quite true, I'm willing to give rat butt to most anyone

[ninethlife]

Soda straw principal. In my boat delivery business, while not often, I do occasionally encounter this misleading phenomena. It's a heart stopper to suddenly find you might have been running the previous day with insufficient oil in a client's mega-dollar toy. And a welcome 'whew' when after unchoking the dipstick, normalcy returns. I've had where one engine did such and the other one didn't. Removing the filler cap has no effect.

[jasonquick]

Fantastic thread.

...and while I do most of my forum reading while on the toilet, this has to be the most enlightening read to date.

...truly.

I purchased a classic wooden yacht a couple of years ago, with a Yanmar 4JHTE...and I observed THE EXACT SAME THING.

sure, I understand a reasonable amount t about vehicle engines, it still have much to learn about marine diesels.

I find myself cracking all seals (on the boat that is), checking and rechecking levels before feeling confident.

Great thread

[GrowleyMonster]

Its the dipstick gnomes. Just ignore them and stick it three times, accept the two that most closely agree. Usually by the second poke the gnomes get out of the way.

[capt jgw]

Also note that when the engine is running, a lot of the oil is up in the bearings and galleries. If you checked the oil with it running, you would get a very low reading. Shut down and let the oil drain a while and the normal level comes back. That's one reason you don't check the oil level on a running engine or immediately after shutdown. The rubber plug on the stick prevents the oil from flowing back up the tube after shutdown. My Universal 5411 is the first engine I've had that did this, and it's the first with a separate sealed dip tube. Everything else the stick just went into the crankcase, and I could just pull it out and look. If the engine had been off a few hours the first reading would be correct.