Should oil leak out of oil pressure sender hole, when sender is removed?

[AndyZee]

Hi!

I am new to motor mechanics. So maybe I am asking a silly question.
As the oil pressure lamp of my Hinomoto E2804 starts to burn after the motor gets warm, I removed the oil pressure sender to check it with air pressure while measuring the electrical resistance.
My question here is, should there be oil coming out of the hole of the oil sender when the sender is removed? I expected the sender to be placed under the motor oil level, but as I got the sender out there was no oil coming out. Yet the oil level according to the oil level measurement stick is correct.
Will get some mechanical oil pressure gauge to check the real pressure, however my attempt at checking the oil sender did at least show a large resistance when air pressure was applied, so I am afraid it will not be a defective sender.

Have a nice day!
Andy

 

[geneP]

You might see a few drops of oil drain from the hole, but the oil pressure sender is not installed below the oil level. It only sees oil that has been picked up and pressurized by the oil pump.

 

[Coyote machine]

Both level on the dipstick and pressure at the gauge are important. First is level, which should be checked when the engine is cold. Remove stick, wipe clean, reinsert, remove and read level. It should be above bottom mark and at or below the top mark. Pressure should be what the engine is specked to run at, maybe 30#/sq. in. or similar. Oil pressure is going to be present at the gauge sender only when the engine is running.

 

[AndyZee]

@geneP Thank you very much for the answer, so its ok that no oil came out.

@Coyote machine Thank you very much, I hoped that oil should come out and that I simply could add more oil to solve my problem, but now I know it is not the case.

So I will get the mechanical oil pressure gauge and will continue to look for the cause.

 

[AndyZee]

One more question though. Should the oil level really be checked when the engine is cold and has rested for some time? Till now I have always tried to check it after I have run the engine for a minute, then waited for half a minute to check the level.

 

[Coyote machine]

Cold is when the oil is at it's highest level in the crankcase, which is where the dipstick measures the level. By running the engine you have used oil to coat all the internal engine parts, which makes the dipstick reading inaccurate. It takes time to drain all the oil back into the pan. The exception to this is after an oil and filter change, briefly run the engine, (for the oil filter to be filled), then shut it off, and measure the level after a few minutes, then an accurate reading will be rendered.

 

[skyhook]

Hi!


My question here is, should there be oil coming out of the hole of the oil sender when the sender is removed?
Andy

When the machine is running, yes. Think of it this way....
You have a garden hose as an "oil passage way" and your sending unit is "tapped" into it in the middle.
When your engine is running, the hose receives pressure from the oil pump and your sender reads this pressure. With the engine off, there is no more pressure, you may have a little oil come out with it off but nothing major compared to when it would be running.

 

[AndyZee]

@Coyote machine, ok thank you for this explanation. In fact I thought the oil level should be in range of the dipstick when the engine is coated in oil, thus after a short engine run. But now I will change the way I measure the oil level.

@skyhook Thanks, now I understand.

I have not yet had time to get a mechanical oil pressure gauge, so I have not got any further with the diagnosis of the problem.