Low Oil Pressure Reading for Kubota

[marinepics]

Hi folks...i'm new to this site, but here goes...
I'm getting the low oil pressure alarm after about 15-20 mins of running my KU28...a Kubota 4 cyl diesel, marinised by Diecon (Australia).
It's quite a new engine..only about 400hrs.
The initial pressure of approx 200kpa drops to about 100kpa after a short while, whereupon the alarm sounds.
Naturally this is somewhat disturbing...it has been suggested to me to change the oil for a thicker type?
would this be sensible advice, or do I need to search for a different solution? any advice will be gratefully recieved...Peter

[Reefmagnet]

Before you do anything, get the oil pressure tested independent of the gauge as it's not unknown for the gauges to read incorrectly. I'm no mechanic, but a drop in oil pressure once warm, if the gauge proves accurate, usually indicates a problem with the big end bearings.

[boris]

Has it got the correct grade of oil ?

[GordMay]

Greetings and welcome aboard the CF, marinepics.

[DeepFrz]

What grade and viscosity of oil did you use on your last oil change? When was your filter last changed?

[gjordan]

See if your oil has been thinned down from diesel getting into the sump from faulty injectors or (more likely) a leak in the lift pump. Feel the oil on the dipstick when cold and feel a little fresh oil to see if there is an obvious difference. Also smell the dipstick since diesel will give it a noticeable smell. If you are in doubt have an oil analysis done and it will tell you if there is fuel contamination or if you have lots of little bits of metal (big problem) flying around inside your engine. Good luck with it.____Grant.

[gjordan]

Another quick thought , Do you have an oil cooler in your system? If so, make sure the oil actually goes thru it. You can also buy oil temp gauges at any good auto parts store. Check with the engine dealer to find the proper place to install it._____Grant.

[S/V Antares]

ok, A gauge is a gauge and does not normally acttuate an alarm. Look for a switch or combo switch sender and see if it has the "Make point" stated on it. (The alarm point). It might be real low. say 4 -5 PSI

[MarkSF]

Originally Posted by marinepics

Hi folks...i'm new to this site, but here goes...
I'm getting the low oil pressure alarm after about 15-20 mins of running my KU28...a Kubota 4 cyl diesel, marinised by Diecon (Australia).
It's quite a new engine..only about 400hrs.
The initial pressure of approx 200kpa drops to about 100kpa after a short while, whereupon the alarm sounds.
Naturally this is somewhat disturbing...it has been suggested to me to change the oil for a thicker type?
would this be sensible advice, or do I need to search for a different solution? any advice will be gratefully recieved...Peter

100kpa is about 15 psi. That sounds very low. The oil pressure warning is probably a separate switch. So your oil pressure switch is consistent with the gauge. So it sounds like you really do have low oil pressure. Best plan is to confirm the oil pressure with a trusted stand-alone gauge.

Better stop running the engine until the cause is rectified, or a moderate bill for whatever is wrong will become an enormous bill for a new engine.

I recently sold a Jaguar V12. The mechanical part of the engine is massively overengineered, almost indestructible, but the cooling system, ignition, and fueling are temperamental so they regularly get destroyed by owners who keep driving it with chronic overheating. Favourite failure : One bank ignition fails, fueling goes into catalysts which catch fire. Number one rule for all engines : don't drive it broken.

[marinepics]

Thanks everyone..I appreciate the response...I have only owned the vessel for a short period. The oil appears clean and transparent, but, since I don't know how long it's been in use, the first thing I'll do is change the oil and filter to ensure that aspect is taken care of...and I'll purchase an oil of higher viscosity.
If the issue still remains, I'll investigate the other suggestions that have been offered.
Many thanks all...I'm not really a mechanic's "bootlace", but, at least now I have some direction.

[shakey doug]

G' day,
You may have a sticking lube oil bypass valve i have this found is problem with a couple of kubota engines displaying exactly the same symptoms.

Solution. Remove oil filter then undo the large nut /stem 19mm from memory, then after placing a rag underneath to catch ball valve and spring withdraw the valve holder. Thoroughly wash the holder and galleries out with diesel checking for any pieces of crud or rough casting, manually check the valve for smooth--- non sticking operation.

Hope this helps, Shakey.

[mikefossl]

Found this: Low Oil Pressure - TractorByNet.com

[marinepics]

Thanks for your suggestions/help everyone..it's much appreciated...I have since discovered from another Kubota owner that the same alarm sounds for the water temp...I am told that Kubotas are "rather prone" to over-heating problems...he has removed the thermostat, and has no more problems, and suggests I try doing the same?? I am wondering what sort of temp should I expect the engine to run at under normal cruising revs?

[MarkSF]

Originally Posted by marinepics

Thanks for your suggestions/help everyone..it's much appreciated...I have since discovered from another Kubota owner that the same alarm sounds for the water temp...I am told that Kubotas are "rather prone" to over-heating problems...he has removed the thermostat, and has no more problems, and suggests I try doing the same?? I am wondering what sort of temp should I expect the engine to run at under normal cruising revs?

For my 3 cyl Kubota the spec is 175 to 185F running temp. Do you have an operators manual? It should say in the specs.

[shakey doug]

G,day
Kubotas, like any engine will run hot when there is an issue some where in the cooling circuit they are no more likely to overheat than any other engine in the same circumstances ,find the issue rather than removing the thermostat. The lube oil pressure circuit and the coolant temp circuit use seperate sensors not related to each other they do share the same siren to alert the operator. Assuming the motor is fresh water the running temp should be around 82c / 180f.