After running my engine for about an hour on a trip this week to Put in Bay the oil pressure alarm came on indicating a pressure on 20 #. I shut off the engine looked for leaks and checked the dip stick and the water temperature. All was ok. So I restarted the engine and the pressure was at 60#s. I continued to run for another 2 hours without incident. Also ran about 3 more hours since then without a problem. My engine is a Universal M-40. Any thoughts? Is it a sensor problem or possibly a oil pump problem? I hope not the later.
Oil pressure problem?
- Thread starter spencer
- Start date
-
- Tags
- oil alarm oil pressure
Sam Vickery
Member III
Spencer,
I have a Universal M25. I was out last Friday, spotted two BLUE WHALES about four miles offshore (not on topic, but amazing) the wind died and I started the engine. Motored into the harbor, throttled back to idle and the alarm sounded. I throttled up and the alarm stopped. ?????? Oil Pressure? It has not happened in the last two outings. I plan on speaking to the mechanic and will let you know what he thinks.
Sam
32-3
I have a Universal M25. I was out last Friday, spotted two BLUE WHALES about four miles offshore (not on topic, but amazing) the wind died and I started the engine. Motored into the harbor, throttled back to idle and the alarm sounded. I throttled up and the alarm stopped. ?????? Oil Pressure? It has not happened in the last two outings. I plan on speaking to the mechanic and will let you know what he thinks.
Sam
32-3
Greg Ross
Not the newest member
On my YanMar panel
On my YANMAR there's no distinction when it goes to alarm between low oil pressure or an "overheat" condition.
Idiot lights only for me, no analog gages yet. Sender could be faulty.
Sam,
What kind of shape is you impeller in? condition of your raw water filter if you have one, pull the intake line off the seacock, flowing freely/ is it by any chance plugged up with critters?
Just one other possibility.
On my YANMAR there's no distinction when it goes to alarm between low oil pressure or an "overheat" condition.
Idiot lights only for me, no analog gages yet. Sender could be faulty.
Sam,
What kind of shape is you impeller in? condition of your raw water filter if you have one, pull the intake line off the seacock, flowing freely/ is it by any chance plugged up with critters?
Just one other possibility.
Last edited:
Sam Vickery
Member III
Greg,
Thanks for the suggestions. I recently replaced my water pump, along with a new impeller of course. I do have a raw water filter, I will check it when I am back at the boat tomorrow. I am lucky to have gauges and the engine temp read right at 180 when the alarm went off. The manual reports 180 is about where it should, be so..... these are some of the things that make boat ownership interesting.
Sam
32-3
Thanks for the suggestions. I recently replaced my water pump, along with a new impeller of course. I do have a raw water filter, I will check it when I am back at the boat tomorrow. I am lucky to have gauges and the engine temp read right at 180 when the alarm went off. The manual reports 180 is about where it should, be so..... these are some of the things that make boat ownership interesting.
Sam
32-3
exoduse35
Sustaining Member
Words on oil...
Oil generally behaves like honey. That is to say at a low temp it can become almost solid and as it heats up it will become like water. The range that this happens is determined by it's weight the higher the wt # the thicker @ ambient temperature and the higher temperature it is designed to run at as it remains thicker than a lighter oil proportionately at all temperatures. Some oil is mixed with an emulsifier that extends it's temperature range. This results in an oil that is thinner at ambient but thicker at operating temperatures. This oil has 2 numbers. the first is it's equivalent @ ambient and the second is the oils equivalent at higher temps. Thus a 10- 40 oil is equal to a 10 weight oil at room temp and a 40 weight oil at about 150*. Oil must be picked up by the pump and passed through the oil passages to where the parts that are moving against each other are being lubricated. The moving parts create friction which creates wear and heat. The oil reduces friction and absorbs heat. If the oil temperature is too low, the pump creates a lot of pressure because the oil is thick and hard to move, but being thick relatively little volume is able to reach where it needs to to work. If the oil is too hot it becomes too easy to move and being thin will pass easily through the smallest spaces making the volume of oil actually in contact with the moving parts to be reduced. The trick is then to get an oil that will pass at a rate that provides maximum lubrication and remains between the parts long enough to absorb the heat. As winter comes a lower weight may be needed to work in a cold engine. As an engine becomes worn it may require a heavier weight oil to compensate for the looser tolerances between worn parts. As the pump turns faster it moves more oil and creates more pressure. At start up excessive revs can create enough pressure to blow out seals, and even at idle will have higher pressure than at speed when warm. It is not unusual to be at or below the alarm set point at idle when it is warm, and it go out just off idle. If the alarm goes off at speed, assuming the sender is good, either the oil has gotten too hot and thinned out or it has been obstructed on the inlet side. A small weight difference in the oil can make a big difference in oil temperature because as the oil thins it stops lubricating causing friction and heat further thinning the oil making the problem compound itself. Everyone is familiar with the water cooling system, however it's function is to cool the combustion chambers where heat is generated mostly by the exploding fuel, however it has very little influence on the oil temp and should be thought of as a separate (mostly) system. An exception to this is if an engine has an oil/water heat exchanger cooler, Even still oil temperatures are in the 120 to 230 range and water temps should stay at 160 to 180. A cooler will bring the two temps closer together. More than anyone cares to know and no direct answer here but understanding how the stuff works gives you the place to start to figure it out. Hope this helps someone, Edd
Oil generally behaves like honey. That is to say at a low temp it can become almost solid and as it heats up it will become like water. The range that this happens is determined by it's weight the higher the wt # the thicker @ ambient temperature and the higher temperature it is designed to run at as it remains thicker than a lighter oil proportionately at all temperatures. Some oil is mixed with an emulsifier that extends it's temperature range. This results in an oil that is thinner at ambient but thicker at operating temperatures. This oil has 2 numbers. the first is it's equivalent @ ambient and the second is the oils equivalent at higher temps. Thus a 10- 40 oil is equal to a 10 weight oil at room temp and a 40 weight oil at about 150*. Oil must be picked up by the pump and passed through the oil passages to where the parts that are moving against each other are being lubricated. The moving parts create friction which creates wear and heat. The oil reduces friction and absorbs heat. If the oil temperature is too low, the pump creates a lot of pressure because the oil is thick and hard to move, but being thick relatively little volume is able to reach where it needs to to work. If the oil is too hot it becomes too easy to move and being thin will pass easily through the smallest spaces making the volume of oil actually in contact with the moving parts to be reduced. The trick is then to get an oil that will pass at a rate that provides maximum lubrication and remains between the parts long enough to absorb the heat. As winter comes a lower weight may be needed to work in a cold engine. As an engine becomes worn it may require a heavier weight oil to compensate for the looser tolerances between worn parts. As the pump turns faster it moves more oil and creates more pressure. At start up excessive revs can create enough pressure to blow out seals, and even at idle will have higher pressure than at speed when warm. It is not unusual to be at or below the alarm set point at idle when it is warm, and it go out just off idle. If the alarm goes off at speed, assuming the sender is good, either the oil has gotten too hot and thinned out or it has been obstructed on the inlet side. A small weight difference in the oil can make a big difference in oil temperature because as the oil thins it stops lubricating causing friction and heat further thinning the oil making the problem compound itself. Everyone is familiar with the water cooling system, however it's function is to cool the combustion chambers where heat is generated mostly by the exploding fuel, however it has very little influence on the oil temp and should be thought of as a separate (mostly) system. An exception to this is if an engine has an oil/water heat exchanger cooler, Even still oil temperatures are in the 120 to 230 range and water temps should stay at 160 to 180. A cooler will bring the two temps closer together. More than anyone cares to know and no direct answer here but understanding how the stuff works gives you the place to start to figure it out. Hope this helps someone, Edd
I hate idiot lights and have no use for alarms, etc. There I said it! What I do like is GAUGES! Luckily my boat came with gauges for water temp, oil pressure, etc. Not that gauges are absolutes, they can be miss-calibrated as my most recent tach experience has shown. What gauges offer is the ability to establish a "norm", as in, the needle "usually" shows x, y, or z. When it does not, that is the time to start paying attention. Since most marine diesels are industrial based I've always been skeptical of worries about oil pumps breaking, etc. These engines are very robust and last for 1000's of hours. If they are running they tend to keep doing so. A pressure gauge would go a long way in diagnosing your problem. That said, I'm guessing the engine was hot, the oil is halfway used or due for a change, and the pressure dropped low enough to trigger the alarm. The alarm may not do this again until the engine good and hot and the oil broken down from use. Was the oil level in the normal range on the stick or a bit low but still okay? Sometimes just a 1/2qt can make a difference. If the engine has some hours on it, this could simply be a case of clearances being a bit worn. Not a big deal at all if the engine runs well, but below the alarm threshold sometimes. I'm guessing you are running a 15w-40 HD diesel rated oil? You probably should be. If you are you could also switch to a straight 40wt HD diesel oil if you are in a temperate to warm climate. The straight 40wt will be more stable at running temp. RT
Thanksguys for all your info and help.
I am using a 30 wt Rotella t diesel oil as per the manufacturers requirements. I do have a oil pressure gauge and water temp guage. When the alarm went off the pressure was at 20 #s where it normally runs at 58 or so. At the time of the incident the water temp was at 180 where it normally runs about 160. When i turned the engine back on the pressure when back to 58 but the water stayed at 180. A couple of days later I when out. This time the oil pressure was good but the water temp went back to 160. Ran everything for about 3 hours. The oil on the dip stick thru it all was just a hair below full. Since my last oil change which I do every 50 hours I had put on 16 hours . The quantity of oil in the pan is rated at 10 qts. When I change it I usually get about 8 to 8-1/2 out so maybe I am not getting it all out. Been doing this for over 10 years though.
I am using a 30 wt Rotella t diesel oil as per the manufacturers requirements. I do have a oil pressure gauge and water temp guage. When the alarm went off the pressure was at 20 #s where it normally runs at 58 or so. At the time of the incident the water temp was at 180 where it normally runs about 160. When i turned the engine back on the pressure when back to 58 but the water stayed at 180. A couple of days later I when out. This time the oil pressure was good but the water temp went back to 160. Ran everything for about 3 hours. The oil on the dip stick thru it all was just a hair below full. Since my last oil change which I do every 50 hours I had put on 16 hours . The quantity of oil in the pan is rated at 10 qts. When I change it I usually get about 8 to 8-1/2 out so maybe I am not getting it all out. Been doing this for over 10 years though.
Sam Vickery
Member III
Greg,Edd & Rob,
Thanks for the insight. Being mechanically challenged, it is always good to have insight into the workings of the "beast" from folks who really know. Your descriptions and advise are greatly appreciated.
Going down to the boat today and will see what happens when I fire her up.
Sam
32-3
Thanks for the insight. Being mechanically challenged, it is always good to have insight into the workings of the "beast" from folks who really know. Your descriptions and advise are greatly appreciated.
Going down to the boat today and will see what happens when I fire her up.
Sam
32-3
On our M25 with 2500 some hours I had the same problem. Turned out the root cause was a worn spring inside the Oil Pressure Relief Valve. I replaced the Relief Valve with one from Kubota as well as a new Oil Pressure Switch and the problem is now gone. OBTW I also plumbed in an old fashioned Oil Pressure Gauge to verify the actual pressures. This was some 4 years ago now. All is still well with over 3000 hrs on engine. All in all pretty easy fix.
Look in the Torrensen Web site, Or at this web page. It might be easy to change.
http://www.marinedieseldirect.com/catalogs/catalog_group.php?owner=mdd&catalog=200142&model=M-25 / M-25XP / M-25XPA&page_ident=200142-9&manufacturer=Universal&title=Gear Case Group&size=800
http://www.marinedieseldirect.com/catalogs/catalog_group.php?owner=mdd&catalog=200142&model=M-25 / M-25XP / M-25XPA&page_ident=200142-9&manufacturer=Universal&title=Gear Case Group&size=800