Kubota V1505 low oil pressure.

welder90

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Lincoln Vantage 300
Nov 27, 2022
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46280
Hello, I'm having an issue with my welder that has the Kubota v1505. I was using the machine and one day it shut down and the oil pressure light came on. It cooled down and when I restarted it the oil pressure was at 75psi (good). As it runs its starts to creep down slowly until it shuts off. I haven't been using it regularly until recently so could it be old oil and a bad filter? It has about 5k hours. Any help would be appreciated, thanks!
 
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85Hokie

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What weight oil you using?

As the unit heats up, what psi does it drop to?
 

welder90

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Lincoln Vantage 300
Nov 27, 2022
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What weight oil you using?

As the unit heats up, what psi does it drop to?
I'm using 15w40. It startes at 75 cold and drops down below 20psi. I didn't let it run until it shut off a second time because I didn't want to damage the engine anymore if it isn't already. I verified the sensor and gauge is working by using a separate mechanical gauge as well.
 

North Idaho Wolfman

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I'm using 15w40. It startes at 75 cold and drops down below 20psi. I didn't let it run until it shut off a second time because I didn't want to damage the engine anymore if it isn't already. I verified the sensor and gauge is working by using a separate mechanical gauge as well.
Pull the oil and look for metal in it.
Sounds like you could have a main bearing issue.
 

North Idaho Wolfman

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I'll be doing that soon and cutting the filter open. If the oil and filter don't have metal shavings then what do you suggest?
Pull the injectors or the glow plugs and see how well the motor turns by hand.
If it feels smooth and easy then I would say you need to pull the pan and check the pickup screen.
After that you'll need to get fully into it.
 
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welder90

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Pull the injectors or the glow plugs and see how well the motor turns by hand.
If it feels smooth and easy then I would say you need to pull the pan and check the pickup screen.
After that you'll need to get fully into it.
OK, thanks! I'll report back with my findings when I get around to it.
 

lugbolt

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if it's got a low oil pressure shut down, that's good. If it doesn't, the engine seized and at that point, using the suggestions above would be wise. I have heard of this fairly often with tractors-and they don't have a low oil pressure cutoff, just an idiot light which almost nobody knows what it means. The ignorant light means the oil PRESSURE is low. Think of oil pressure the same as blood pressure. If it's "that" low, there's usually other problems.
 

welder90

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Lincoln Vantage 300
Nov 27, 2022
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if it's got a low oil pressure shut down, that's good. If it doesn't, the engine seized and at that point, using the suggestions above would be wise. I have heard of this fairly often with tractors-and they don't have a low oil pressure cutoff, just an idiot light which almost nobody knows what it means. The ignorant light means the oil PRESSURE is low. Think of oil pressure the same as blood pressure. If it's "that" low, there's usually other problems.
It does have a low oil shutdown and the engine isn't siezed. After it shut down the first time and the idiot light came on I let it sit for a while and then hooked up a different oil pressure gauge just to make sure the original gauge and sensor were both in working order before starting it again.
 

85Hokie

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Bedford - VA
It does have a low oil shutdown and the engine isn't siezed. After it shut down the first time and the idiot light came on I let it sit for a while and then hooked up a different oil pressure gauge just to make sure the original gauge and sensor were both in working order before starting it again.
WHAT was the OIL pressure looking at the gauge - WHEN you shut it down?

Many old tractors ( IE - ford 8N ) would warm up and the PSI at idle would be about 5 psi ..... that may seem very low, but those engines (GAS) would run forever! Your fuel delivery is typically 3-5 PSI.

If your sensor is cutting out at "20 psi" then - yes you have a pressure problem - but I doubt that you have hurt anything.
 
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#40Fan

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You might have an oil drain back issue where all of the oil is being pumped to the top of the head and the ports that allow it to flow back to the pan are blocked off. With the oil fill cap off, how far can you see down into the valve cover? If there isn't a metal baffle in the way, after running it for a while and seeing the pressure drop, shut it down and remove the cap. Take a peek inside.
 

welder90

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Lincoln Vantage 300
Nov 27, 2022
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46280
WHAT was the OIL pressure looking at the gauge - WHEN you shut it down?

Many old tractors ( IE - ford 8N ) would warm up and the PSI at idle would be about 5 psi ..... that may seem very low, but those engines (GAS) would run forever! Your fuel delivery is typically 3-5 PSI.

If your sensor is cutting out at "20 psi" then - yes you have a pressure problem - but I doubt that you have hurt anything.
I shut it down when it reached about 18-20psi. It wasn't holding steady on just one number. The gauge was fluctuating +/- 2 or 3psi I'd say. To me it seemed much too low for a diesel engine and I didn't want to continue running it until I got some suggestions or answers on where to start.
 

welder90

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Lincoln Vantage 300
Nov 27, 2022
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46280
You might have an oil drain back issue where all of the oil is being pumped to the top of the head and the ports that allow it to flow back to the pan are blocked off. With the oil fill cap off, how far can you see down into the valve cover? If there isn't a metal baffle in the way, after running it for a while and seeing the pressure drop, shut it down and remove the cap. Take a peek inside.
Will that still be useful since my oil fill is on the side of the block?
 

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85Hokie

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BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
Jul 13, 2013
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2,164
113
Bedford - VA
I shut it down when it reached about 18-20psi. It wasn't holding steady on just one number. The gauge was fluctuating +/- 2 or 3psi I'd say. To me it seemed much too low for a diesel engine and I didn't want to continue running it until I got some suggestions or answers on where to start.
On my B7100 (30 years old) - when I cut grass and work that machine hard in the summer - temps run 215-218 F on my temperature gauge (added aftermarket) and my oil starts off hitting 55-60 psi (aftermarket gauge) - after an hour of cutting when I pull the throttle back it will be sitting at 15 at a low idle, if I bump it up a small amount it climbs to 20+. I'm glad I have no such kill switch!:D
 

lmichael

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Kubota G2160
Apr 23, 2021
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Rockford IL area
Have you confirmed the sensor circuitry is operating correctly? Possibly a wonky sensor. I've seen more than one oil pressure or temp sensor go bad in my day. And sometimes believing. Maybe try bypassing it and put a strictly mechanical gauge in place. Run the engine up to temp and wach carefully
 

welder90

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Lincoln Vantage 300
Nov 27, 2022
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46280
Have you confirmed the sensor circuitry is operating correctly? Possibly a wonky sensor. I've seen more than one oil pressure or temp sensor go bad in my day. And sometimes believing. Maybe try bypassing it and put a strictly mechanical gauge in place. Run the engine up to temp and wach carefully
I put a brass T in the sensors place then a mechanical gauge and then sensor on the very end. Both gauges, the mechanical and machine, were reading the same PSI. I didn't know how to bypass the sensor. Would having the sensor still connected give a false reading to the mechanical gauge even if the mechanical gauge received oil before the sensor does?
 

lmichael

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Kubota G2160
Apr 23, 2021
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I put a brass T in the sensors place then a mechanical gauge and then sensor on the very end. Both gauges, the mechanical and machine, were reading the same PSI. I didn't know how to bypass the sensor. Would having the sensor still connected give a false reading to the mechanical gauge even if the mechanical gauge received oil before the sensor does?
I doubt it. Sorry I missed that. but, if the sender is leaking perhaps but then you would have lost oil
 
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#40Fan

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Will that still be useful since my oil fill is on the side of the block?
Peek through this one.




ETA: You could also pull the dipstick and see how much oil is on there, immediately after shutting off. Keep checking every minute or so and time how long it takes to get back to the full mark.

2nd ETA: Can you pull the fill cap that you use now and look inside? Does it look like it is clean or gummed up with sludge?
 
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welder90

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Lincoln Vantage 300
Nov 27, 2022
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Well everyone I appreciate all your help. Come to find out there are metal shavings in the oil filter. Looks like a rebuild on my hands but considering it was a rental machine before I bought it I don't think it's worth the investment. Thanks everyone!
 
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