Universal M-25 dipstick mysteries

[Dean Abramson]

Our engine has always been this way. When you first pull out the dip stick, when the engine has not been running recently, the dipstick reads empty. The first dip it will show oil, sometimes what I finally deem to be “correct;” but often if I do 2-3 dips, each one will show slightly more. When I get two in a two identical readings in a row, I call it Correct, and act accordingly. This pattern has been remarkably consistent all these years.

Once I attended a day-long diesel class at Hansen Marine, a big Universal dealer. The guy said my scenario is totally normal and explained why. Of course I now forget why.

For years our boat has used a bit of oil. Let’s say six hours of motoring might mean 2-3 ounces to top back up the next day. This pattern also has been stable. Most times I check, it’s down about 1/4 inch on the dipstick, and I add a very small glug.

Recently we had a valve job done, and we also had a remote oil filter installed. The first few trips, everything was as usual. So each day I was adding a few ounces. After I put a tad in, I don’t dip again; I just go. Sometimes one needs to have a little faith.

Okay, so I take recent trip; situation normal. Last morning of that trip, I added a tiny glug.

Now this trip. Arrive at boat, check oil ... and find it 1/4” OVERfilled. So I conclude the last glug was too generous. But now we’ve been underway for three days, maybe 8 hours of motoring total ... and the level is exactly as overfilled as it was. Suddenly the engine seems to burn no oil.

???

Have at it, ladies and gentlemen!

[Steve Laume]

I don't know the answers but I have the same issues with the dip stick.

How can a stick in some oil not work?

I have an M20.

[Dean Abramson]

How can a stick in some oil not work?

Funny!

Really, right? Crazy.

[bottomscraper]

So when they did the valve job they may have also replaced or reamed the valve guides and replaced seals. (I have no idea what would be standard procedure for an M-25). Leaky valve guides or seals may have been the reason for the oil being lost before the valve job.

That still doesn't explain the dipstick. I can tell you that the dipstick for the transmission on my Kubota tractor behaves the same way. Pull it out and it looks dry, stick it in an check again looks fine.

"I think I'll just let the mystery be" Iris DeMent

[jbenagh]

Is it possible that when running the engine, the level drops and then can't fill up again until you release the seal at the top of the dipstick? If it had been sitting a while, maybe even overnight, oil could have flowed off the stick.
Jeff

[Dean Abramson]

So when they did the valve job they may have also replaced or reamed the valve guides and replaced seals. (I have no idea what would be standard procedure for an M-25). Leaky valve guides or seals may have been the reason for the oil being lost before the valve job.

That still doesn't explain the dipstick. I can tell you that the dipstick for the transmission on my Kubota tractor behaves the same way. Pull it out and it looks dry, stick it in an check again looks fine.

"I think I'll just let the mystery be" Iris DeMent

Love the Iris Dement quote! I know that song. Yep, might have to accept that I simply have not been chosen to understand this.

[Dean Abramson]

Is it possible that when running the engine, the level drops and then can't fill up again until you release the seal at the top of the dipstick? If it had been sitting a while, maybe even overnight, oil could have flowed off the stick.
Jeff

Maybe, Jeff. But that does not make sense to me. Which is not to say that’s not the answer. I don’t know enough, obviously. I don’t really know exactly how/where the dipstick tube interfaces with the oil, to be honest.

Anyway, sounds like I’m in good company, and I’ll stick with the multiple dips.

Thanks for responding.

[Paul D.]

This breaks my paradigm of Kubota diesels not having bizarre idiosyncrasies. This should be a Volvo or Perkins or something. (Mind you, our 5424 never gets up to stated temperature.) I don't know how I feel about it and I certainly cannot think of anything that would cause that except some sort of air pressure broken by opening the dipstick. Now I won't sleep for a few nights I guess.

[Dean Abramson]

Rich, I think you nailed it re the oil consumption. We did get new valve seals. I was focused on thinking about piston rings, and never thought about oil getting burned by coming in that way.

[Steve Laume]

I tried all sorts of things to try to get the dip stick to read consistently. Removing the filler cap or breaking the seal on the dip stick and letting it rest had no effect. One trip, I tried using the first, low, reading and added oil accordingly. That resulted in burning up a bunch of oil and a sooty transom. You can't really count on measuring the amount of oil you add during an oil change because I doubt that you can ever remove all the old oil with the engine sitting at an angle. I will try the law of averages trick this year if I ever get Raven back in the water. I am close and she is going to be awesome when we splash in the next week or so, Steve.