When to Add Oil/Water

Would like some input. When checking engine oil, should oil be topped up when the level drops below the "full" mark or when it drops near the "low" mark? And, should batteries be topped up to the slot on the fill neck or just be sure the plates are always covered? Thanks, Howard

I think it depends on engine and the angle of the installation. My DD 8V71 stays just above the low level mark. Add more and it burns off (leaks) back to that level, then stays there.

I think the oil dipsticks were calibrated to reflect the proper high/low levels as they are engraved onto the sticks and differ from the original factory marks. My question; is it OK not to add oil if the level is between the marks and the oil pressure is normal?

Yes it absolutely ok to wait till the oil level gets down to the "add" mark. That's the reason for the 2 marks. Anyplace between the 2 marks is good.

Ken

That's what I thought. Thanks.

Some batteries such as Rolls are designed to be filled as much as a quarter inch below the vent well tube/neck, ; Trojan says 1/8" below. Check with the manufacturer.

We'll add a quart of oil when the engine is down a quart.

For batteries, we use one of those battery autofill bottles that has a push-to-fill nozzle that stops the flow of water when the level is correct in the cell. I believe it stops just short of the top of the cell.

Greetings,
Mr. hm. Like Mr. Marin, we use one of these and it works great for those back batteries that are harder to reach or observe. Takes the guesswork out.
Amazon.com: Plews 75-030 Auto Shut Off 2 Quart Capacity Plastic Battery Filler: Automotive

I add oil depending on a number of variables.

In the summer I keep them full especially an engine I'm going to work hard. Don't want to be climbing a mountain pass trying to keep up w traffic a quart low. Or even 1/2 a quart low. In a boat where I'm going to run fairly hard ... same thing. The idea being that the oil temperature will be higher and viscosity down.

Under lighter loads and cooler temps running a quart low is fine IMO. If I was going to go up to town (10 min on level roads) w my 455 Buick .. also fine. Low temps ... low loads.

But I never run lower than the "low" mark on the dip stick.

dimer2 said:

I think it depends on engine and the angle of the installation. My DD 8V71 stays just above the low level mark. Add more and it burns off (leaks) back to that level, then stays there.

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A lot of engine are like that.

To the OP, let yours work it's way toward the low mark and you may find it finds its happy place before reaching the low mark and stay there for quite a while.

Capt.Bill11 said:

A lot of engine are like that.

To the OP, let yours work it's way toward the low mark and you may find it finds its happy place before reaching the low mark and stay there for quite a while.

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We had a Perkins for 10 years and it took us 5 years to determine the oil low mark was where she stopped losing oil. To keep it at the low mark, we would add ~1 quart per 100 hrs. vs ~1 quart per 20 hours to keep the level at the full mark.

I had one of those auto fillers, but unfortunately it over filled both the Rolls(especially) and Trojans.

The operation manual for our Yanmar 4JH2 says to check the oil 3 minutes after shutting down. Was scratching my head for a while (and getting variable readings) before I found that tidbit of information.

Capt.Bill11 said:

...
To the OP, let yours work it's way toward the low mark and you may find it finds its happy place before reaching the low mark and stay there for quite a while.

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My truck engine is very much likes to run at the low end of add range of the dipstick. If I add oil it will quickly get consumed towards the low end of the range.

My Yanmar engine in my JD tractor does not use oil so it never needs make up oil.

When to add oil depends on the engine.

Later,
Dan

>The operation manual for our Yanmar 4JH2 says to check the oil 3 minutes after shutting down<

This is very common for many engines.

Our preference cruising is a Post Operation , after shutdown check.

Not an AM before use check.

This means should we need to do a hasty departure ,or midnight anchor reset no problem , every thing is 100%.

On the DDs I have had ,keeping the oil level at the high end of the stick, will look as if the engine is overfilled if later checked after hours of sitting.

Staying on the low side cold, will show at least a gallon under the low mark if checked at 3 min after warm shutdown.

Its the running oil level that counts , not the oil level cold.

Oil does far more than just lubricate , and is far easier to install than engine parts.

FF said:

Staying on the low side cold, will show at least a gallon under the low mark if checked at 3 min after warm shutdown.

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I read related posts to this issue on BoatDiesel and most Yanmar manuals seem to recommend checking 10 minutes after shutting down. Why 3 minutes for the 4JH2, I have no idea, but is good evidence why picking up the operation and service manuals occasionally for some light scimming is a good idea...especially those new to the game, like me.

Engines are installed at various angles. That's why dipsticks are calibrated at installation. Were they calibrated correctly is often the question.

My engines hold 5 gallons but stop using oil when the level gets down by 1/2 gallon. IMO someone marked the stick at 5 gallons despite the angle causing oil to be too high. 1/2 gallon down shows up on the stick as midway between add and full. That's where I run it.

After reading these opinions, I have decided to run the engines until the oil level approaches the low mark to see if in fact it does find a comfortable level. I won't let it get too near the low mark since as stated previously, who knows if the stick is correctly calibrated. Thanks to all, Howard

hmason said:

After reading these opinions, I have decided to run the engines until the oil level approaches the low mark to see if in fact it does find a comfortable level. I won't let it get too near the low mark since as stated previously, who knows if the stick is correctly calibrated. Thanks to all, Howard

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As long as the usage is reasonable and you can guess about how much usage there is...don't be scared about getting down near the low mark...while not recommended to run it that way forever...I have run engines well below the mark...even off the stick and still had oil pressure and no damage to the engine.

It wasn't by choice..more commercial ops and getting the job done.

dimer2 said:

I think it depends on engine and the angle of the installation. My DD 8V71 stays just above the low level mark. Add more and it burns off (leaks) back to that level, then stays there.

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Excellent advice. Cummins here and they do the same thing. One of the reasons is that most marine diesels were once used in an application other than marine where they had the luxury of being mounted in level position and remaining that way during operation. Marine diesels do not have that luxury. And to aggravate things, some installations do not allow for oil pan clearance so the "marinizer" installs a shallower oil pan causing oil to puddle in the rear of the oil pan and potentially leak out of breathers and such. That is what Cummins did. And they are the rare case where they are the engine manufacturer AND the marinizer.

This is a small article from the Cummins guru Tony Athens. It may or may not be applicable but you might find a nugget of info in it.
Taking the MYSTERY out of oil pan capacities

This information is most interesting. I will report back on what happens when I allow the oil level to drop.

In 1973 I built a boat, installing a NEW engine, a Cummins V-504M.
Set-up by Da Book.

1: Pull the dipstick out
2: Add (X) amount of oil
3: Wait 5 minutes, insert and pullout the dipstick
4: Mark the dipstick (low level)
5: Add 1 gallon of oil
6: Repeat steps 3 & 4 to mark high level.


In operation oil level checks were to be made 5 minutes after shutdown.

My present engine, a Caterpillar, the oil level is checked with the
engine running.

Ted