120 lehman loss of oil pressure

[Randomwake]

Putting along after 2.5 hours post oil change. Engine dies. No oil pressure at all!!! Dipstick level bang on. Pulled oil filter no contaminants. Engine died before low oil buzzer??? So didn’t spend anytime running without oil….. any idea? Thanks!!

 

[BruceK]

On that information I`d guess the oil pressure dropped because the engine stopped. Not vice versa. The recent oil change may imply a nexus, but I suggest checking other things, like fuel. And,did you change/drain/refill the injector pump oil too?

 

[TowLou]

Drop the pan check your sump and pump.

In all reality the low oil pressure may be a result of the motor cutting out. Check your fuel system.

 

[psneeld]

Did you notice engine temp prior to engine shuttling down?

If the engine died and then you checked the pressure, as posted by BruceK, perfectly normal.

If still worried about oil issue.....can you still manually turn the engine with a bar? (would be nice to feel with injectors out).

 

[Old Sea Dog]

I am inclined to think it is a fuel issue as well.

 

[jleonard]

I also would look for a fuel issue. Did it sputter and die? Or just stop dead ?

 

[OldDan1943]

No one mentioned changing the pressure sensor.
Just a thought.

 

[High Wire]

The loss of oil pressure could have been a loss of power to engine harness or gauge. The rule of thumb is “ believe your instruments until proven wrong “.
You can hook up a temporary mechanical oil pressure gauge to prove oil pressure. If you don’t get pressure on a mechanical gauge, stop immediately and get help.
A quick test of the gauge circuit is to power up engine harness with the engine not running, gauge(s) should read zero psi. Then short the pressure sender’s two leads with a jumper lead. The gauge will either stay at zero or peg high. Then remove the jumper and one lead off the sender, it should then peg the opposite direction.
On the unexpected shutdown, does your engine have an electric fuel pump?

 

[rgano]

Does the engine still turn over with the starter. Have you cracked open the bleed screw on the injector pump and pumped the lever on the lift pump to see if you get solid fuel and no bubbles coming out?

 

[Lepke]

Before taking things apart, get a manual gauge and screw it into the sender port. Crank the engine with the throttle off. You should see pressure. To crank w/o the key, jump a small wire between the starter battery terminal and small contact on the solenoid. See image.

No pressure is very unusual and not likely. You'd have to have an oil pump failure or a plugged suction strainer. Even with an oil port open, you'd see some pressure.

 

[twistedtree]

Putting along after 2.5 hours post oil change. Engine dies. No oil pressure at all!!! Dipstick level bang on. Pulled oil filter no contaminants. Engine died before low oil buzzer??? So didn’t spend anytime running without oil….. any idea? Thanks!!

Did the engine die, then you noticed no oil pressure? Or did you notice no oil pressure, or perhaps get a low oil pressure alarm, followed by a shut down? The order matters.


Does anyone know if Lehmans are typically equipped with a low oil pressure automatic shutdown?

 

[Comodave]

I don’t think they are equipped with an automatic shutdown.

 

[psneeld]

never know what POs rigged.....

 

[Patclem]

Did you take the plastic off the oil filter? Just kidding, sort of.

 

[PM]

I would have no worries about attempting a re-start. A diesel engine will start with no oil pressure. It happens every day with every diesel.

Sounds like a fuel issue.

pete

 

[grumpyfnq]

Bt confused as to actual sequence of events and agree with others could be fuel issue.
not fuel issue, find location of oil pressure relief valve. Had an engine drop from 60 psi to 10-15 psi and convinced something drastic, think about how to get out of boat or strip down in place, neither attractive. Saw comment in a thread to check oil pressure relief valve which in this case was part of filter spigot and sure enough it was jammed open for no apparent reason. freed up and 60psi again. Easiest rebuild ever. Broken spring rather than jammed half open would give very low pressure if any.
Just a random thought. Good luck.