What is normal oil pressure range for Universal model 25XP?

A

Alan Clendinen

Member II
Hello group,

I have a 1987 E-35 MK-3 with a Universal model 25XP engine. While running the engine yesterday, the oil pressure gauge was at 30, but after dropping to idel about one hour into our journey, the oil pressure alarm suddenly came on, and the gauge read 10.

We boosted the throttle back to cruising speed, and the oil pressure went back up to 30.

The following day, we returned home. The oil pressure initially showed around 60 at initial start-up, and gradually tappered down to 30, but upon entering the marina and dropping to idle, the oil pressure came on and once again, the gauge read 10. Then we noticed that there was oil in the bilge. We couldn't find the source of the oil leak upon a cursory inspection. I should also mention that this is the first time we took the boat out after a recent oil change, so I'm wondering if the mechanic may have messed up something.

Looking in both the Ericson 35 owners manual and the Universal engine manual, I was unable to find any mention of what the acceptable oil pressure range should be. We had checked the oil dipstick each time before starting the engine, and it showed the proper level.

Alan
 
HughHarv

HughHarv

Hugh
Oil pressure

Two things stick out in my mind, the recent oil change and the fact that your dipstick is indicating you have correct oil level.

If you have oil in the bilge, and you have normal oil level indicated on the dip stick, maybe you don't have low oil pressure but have a loose connection at the oil pressure sender?

If you have oil in the bilge, and the dipstick begins to indicate that your oil level is decreasing, maybe your oil filter gasket is not seated correctly or the oil drain plug is loose or cross-threaded?

Get the mechanic to check their work. Or, if you want to know more before you call in the mechanic, I'd check the oil level, wipe up the oil in the bilge, maybe put some paper or cardboard under the motor to show drips. Start the engine, check pressure, then look at everything the mechanic might have touched, especially the oil filter and oil drain plug (might need a mirror). Also, wiggle the connections to the oil pressure sender to see if the alarm goes off.
 
HughHarv

HughHarv

Hugh
I forgot about the oil pressure range, oil pressure is controlled by a ball and spring which holds back oil flow to keep pressure up in the system. The oil pump is mechanical and as the engine rotates faster the pump speed and pressure increases. If your oil level is okay and your engines turning a couple thousand revolutions per minute when the pressure drops suddenly I'd think it was the oil pressure sender that is not functioning correctly (bad connection or wore out sender). Sounds like you motored long enough that you would have ruined the rod bearings and heard a lot of clanging if you had a bad oil pump or insufficient oil.
 
A

Alan Clendinen

Member II
Harvey,

It was only when I throttled back to idel speed that the oil pressure alarm sounded, and the gauge read only 10. While underway at cruising speed, the oil pressure gauge read 30.

The amount of oil in the bilge wasn't that much. I didn't look at the oil dipstick level after discovering oil in the bilge, but I'll certainly do that when I get back to the boat. When I checked the oil level before starting this short trip, it was normal, and when I checked it the next day before heading home, the oil level didn't look noticeably different.

Alan
 
HughHarv

HughHarv

Hugh
Universal Diesel posts manuals on their website, may also find them under Westerbeke, sister or parent company. They would give you a range, my guess is that 10psi is below the lower limit, hence the alarm. As this hasn't happened to you before, I think it warrants further investigation.

Course, someone else might want to chime in here as a light load on the engine at idle the pressure at 10psi may not be critically low as the bearings are still receiving oil.

I have heard of the gaskets on oil filters popping out of their groove on installation and causing leaks and oil pressure problems. A loose or stripped drain plug wouldn't change your oil pressure till you were really low on oil. You would have an obvious continuous drip or steady draining of oil, depending on how loose it got.

If you have a lot of hours on your engine, you could have a worn oil pump or weak spring pressure in the oil check valve inside the pump which regulates the oil pressure. First rule out everything else, like leaky filter, a used up oil pressure sensor or poor wire connection or short.
 
N

newgringo

Member III
Had same problem on M25

Alan,
We had identical problem on ours. Problem was 2 fold. First, yes the oil pressure does drop in a hot engine at idle speed. 10 psi is OK as long as everything else is ok and the pressure comes up with higher engine rpm. Now to the solution. First- my oil pressure sensor switch was old and tripping at about 15 psi. Of course the light comes on. Replaced the sensor with one from Kubota ($16.41 incl S&H). It tripped at a lower pressure, 5 psi so the light did not come on. Second was to replace the Oil Pressure Relief Valve Assy from Kubota ($29.50 incl S&H). It cracked at a higher pressure than the old one at 14 psi vs 10 psi. So, as you can see we are dealing with some low pressures. I also added an engine box exhaust fan to draw out hot air from the top if the engine box. Helps to keep the engine oil cooler (maybe a little anyhow). All in all these things solved my problem. I did disassemble the Relief Valve and found the spring worn which I think contributed to the lower cracking pressure (2800 hrs on engine). If you do decide to change the Relief Valve it is pretty easy. I drilled a large enuf hole in the front motor mount bracket to access the Relief Valve. It is aluminum and a standard wood cutting hols saw buzzed right thru it. :p. So there is hope. If you want parts numbers I have them or Ronnie at www.tractorsmart.com can help. You will need to know if you have a D850 or D950 engine. It is printed on the injector pump somewhere.
 
A

Alan Clendinen

Member II
Jerry,

Jerry,

I have the Universal engine manual, but it says nothing about acceptable oil pressure range. The other issue is the oil I found in the bilge, and I think it likely that this has something to do with the low oil pressure, but I have not yet figured out where the oil is leaking from. The mechanic who did the oil change didn't drain the oil via the drain plug, since it is not very accessible. He drained it via the dipstick tube. I couldn't find any evidence that the oil filter was leaking, so that mystery continues. Thanks for the suggestions on replacing those other parts.

Alan
 
N

newgringo

Member III
Official Oil Pressure M25

Alan,
In Universal Manual No. 1-89 the Specifications state the oil pressures are:
At Idle Speed 10 psi (I assume this is minimum psi?)
At Rated Speed 28 to 64 psi
As for leaks ??? Don't like them myself. If big, must fix. If little, tolerate:mad:
Jerry
 
B

Brian K

Member III
Alan, check the drain "plug" and make sure it's tight. It's a 3/4" wrench size and extremely difficult to reach. I was bringing my E-32-200 (with the Universal M25XP engine) from E. Greenwich RI to Fair Haven on Lake Ontario. At the start of the 8th day (last day of the trip) I found a lot of oil in the engine sump (which was spotless prior to this mishap). It turns out the oil drain plug on this engine, which is not your typical oil drain plug, had worked it's way loose a little bit and leaked probably a quart of oil into the sump. What a mess, and it took a while to figure out where the oil had leaked from. It's probably a good thing to check on at least an annual basis.
 
A

Alan Clendinen

Member II
Brian,

The mechanic who did the oil-change didn't drain the oil via that drain-plug, due to its lousy access. Nevertheless, I'll make sure to check it; that oil is leaking from somewhere. Thanks for the suggestion.

Alan
 
B

Brian K

Member III
I don't believe mine was ever changed via the oil pan drain plug - who would, who could? The remote drain tube attached to the oil pan plug appears to be factory installed. The plug in my oil pan just came loose over time from the engine vibration I assume.
 
Loren Beach

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Brian K said:
I don't believe mine was ever changed via the oil pan drain plug - who would, who could? The remote drain tube attached to the oil pan plug appears to be factory installed. The plug in my oil pan just came loose over time from the engine vibration I assume.
Click to expand...

Note that the "remote drain" hose is attached to a barb fitting on the side of the banjo fitting that replaces the drain plug. That banjo fitting has a gasket just like any plug would have.

After over 15 years, I removed that fitting from our M25XP sump to put a new hose on it and also had to replace the gasket. It is difficult to work under the engine on our model but I can at least barely see the fitting and can get a wrench on it...

Loren
 
E

Emerald

Moderator
Prior folks have hit many probable causes - oil filter seal/leaks/spills/etc. However, if you could answer one key question, the mystery would be greatly clarified. You have a gauge and noted the values now the alarm has sounded. What was the normal idle pressure and normal running pressure? If these values are the same, then you may have nothing more than a faulty sending unit (or wiring fault) on the alarm. I had this happen last spring on Emerald. Suddenly the overheat alarm is sounding. I go through all the basics, and when it was all said and done, the sending unit for the alarm had failed. She did not have an actual temperature gauge, and now she does. This way I know what temperature she really is running at, and can see changes as they happen instead of waiting for failure. Also they (alarm and gauge) act as a cross check. :cool:
 
A

Alan Clendinen

Member II
David,

That's a good question. Unfortunately, we are new owners, and must admit that until now, we hadn't paid much attention to the oil pressure gauge, since its alarm only sounded at initial startup, which is normal. So we really don't know what the oil pressure gauge read at idle before this problem began.

I can only tell you that at cruising speed, the oil pressure reads between 30 and 60, which according to the engine manual are within the normal range.

Alan
 
A

Alan Clendinen

Member II
Loren,

i'm not sure if our engine has a"banjo fitting" but after looking at it yesterday, my wife described a larger diameter hose attached to the drain, which then had a smaller diameter hose inserted into it and wrapped with tape. The tape was loose, and I suspect this may be the source of the oil leak. I don't know if this kludgy oil-drain hose attachment is causing the low oil pressure alarm to go on when we drop to idle, but we'll certainly change this to a more secure fitting.

Alan
Loren Beach said:
Note that the "remote drain" hose is attached to a barb fitting on the side of the banjo fitting that replaces the drain plug. That banjo fitting has a gasket just like any plug would have.

After over 15 years, I removed that fitting from our M25XP sump to put a new hose on it and also had to replace the gasket. It is difficult to work under the engine on our model but I can at least barely see the fitting and can get a wrench on it...

Loren
Click to expand...
 
Loren Beach

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Alan Clendinen said:
Loren,

i'm not sure if our engine has a"banjo fitting" but after looking at it yesterday, my wife described a larger diameter hose attached to the drain, which then had a smaller diameter hose inserted into it and wrapped with tape. The tape was loose, and I suspect this may be the source of the oil leak. I don't know if this kludgy oil-drain hose attachment is causing the low oil pressure alarm to go on when we drop to idle, but we'll certainly change this to a more secure fitting.
Alan
Click to expand...

Well, what do ya know.... Our '88 came with a similar sounding hose within a hose going there. FWIW there was a Universal diesel option for that banjo fitting and attached hose that became standard equipment a few years later.
I used that hose for my oil drains, with a vacuum "slurping tank" for years before noting that the hose was oily and soft (it was actually a clear vinyl hose with the red thread spiral wrapping in it like the hose used for the hot water side of pressure water systems.)
:rolleyes:
Anyhow, once I got the old fitting off, it could be properly re-installed with new high temp/pressure black hose and re-gasketed. Works fine with no seepage now.

I will later try to get some pics, but close up photos in tight quarters are not my forte.

Sidebar: IMHO this is a "tidiness" issue, and should have no bearing on your engine oil pressure when running.....

Edit: Now adding some photos showing the hose connection and the home-brew way I secure the top of the hose. At the top note the little red plastic tie that goes thru a hole in the dowel.

Loren
 

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A

Alan Clendinen

Member II
Jerry,
I have two versions of the Universal engine manual, but neither of them have any of the data you cite concerning acceptable oil pressure ranges for the M-25XP. If you found this manual online, could you please give me the link so I can download it? Thanks!
Alan
newgringo said:
Alan,
In Universal Manual No. 1-89 the Specifications state the oil pressures are:
At Idle Speed 10 psi (I assume this is minimum psi?)
At Rated Speed 28 to 64 psi
As for leaks ??? Don't like them myself. If big, must fix. If little, tolerate:mad:
Jerry
Click to expand...
 
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