Oil Pressure vs Oil Level

[beermak]

hi to everyone, ive seen something really strange for the last 3 weeks. The oil gauge seems to be between 35 and 40 but when the oil it topped to FULL the pressure drops to 15/20 then over 4 or 5 hours of use will go again to 35/40.

i have the dipstick and im thinking aint showing the right amounts... Full is over the "real full" and its getting more oil than what it should and thats y the pressure drops. am i right?

the gauge is working (not sure how well) because it went from 40 to 15 and then back to 40.

any ideas?

 

[Don S]

Re: Oil Pressure vs Oil Level

If it's overfilled and the crankshaft is aerating the oil, it should also be making the lifters noisy. Does that happen?
Drain all the oil and refill with 1 quart less than book and see what the dipstick says.

What engine we talking about?

 

[boat1010]

Re: Oil Pressure vs Oil Level

The only reason the the level of the oil should effect the pressure is when it gets so low it will not pump then it will go to "0". Sounds like to me you have a problem with the sending unit.. Unless like Don says and it is "over full"

 

[matt167]

Re: Oil Pressure vs Oil Level

Oil level really has nothing to do with oil pressure, unless you'v got it over full and it's causing cavitation with the oil splashing by the crankshaft rotation. Cavitation will cause foam, and that's not going to pump great.. Don't rely on the stick because I'v seen the tubes pull out slightly, and that changes where the oil will rest at 'full'. If you fill it to the full mark, and the tube is pulled out a little, than you will overfill the crankcase.. Drop the oil, and put in the spec'd amount of oil, start and run it 60 seconds or so. and then check the dipstick to see if it's right.. Also make sure the dipstick tube is seated.

Edit. Don replied before I hit the submit button

 

[Bill3434]

Re: Oil Pressure vs Oil Level

Your oil pressure will go up as the oil and engine block gets hot but I wouldn't think there would be that much of a difference. My next question is why kind of engine are we talking about. Diesal or gas, industrial or consumer. When I was an equipment operator in the army decades ago we didn't care how much oil was in the block the only thing we cared about was oil pressure and it had better be up to the proper cold pressure within about 45 seconds of start up or we shut it down in a hurry. The threat was if we didn't, we would be paying about several hundred thousand for it, that is for commercial diesals.

 

[Fishermark]

Re: Oil Pressure vs Oil Level

i have the dipstick and im thinking aint showing the right amounts... Full is over the "real full" and its getting more oil than what it should

How are you checking the oil? The best and most accurate way is to check it when the boat is on the water. If it is on the trailer it could be an an angle that is giving you a false reading on the dipstick.

 

[glenn property of pam]

Re: Oil Pressure vs Oil Level

hi to everyone, ive seen something really strange for the last 3 weeks. The oil gauge seems to be between 35 and 40 but when the oil it topped to FULL the pressure drops to 15/20 then over 4 or 5 hours of use will go again to 35/40.

i have the dipstick and im thinking aint showing the right amounts... Full is over the "real full" and its getting more oil than what it should and thats y the pressure drops. am i right?

the gauge is working (not sure how well) because it went from 40 to 15 and then back to 40.

any ideas?

what im reading is that you fill to the full mark then 4-5hrs later the level is back to where you started and the oil pressure is back to normal. depending on the type of motor theres the basics to check like the oil breather system when blocked this will cause internal pressure that will lead to all sorts of problems as the oil can not drain as designed. make sure the engine is level when you fill with oil so if this is a boat on the trailer make sure the engine is level.

 

[boat1010]

Re: Oil Pressure vs Oil Level

Your oil pressure will go up as the oil and engine block gets hot but I wouldn't think there would be that much of a difference. .

As the motor heats up, usually the viscosity decreases and the oil pressure goes down.

 

[Bill3434]

Re: Oil Pressure vs Oil Level

True but it is also easier for the oil pump to pump more oil thas is why I said there shouldn't be that much of difference. Thought about this last night, when it comes to army diesels you only check the oil as an after operations checks. Oil pressure is more inportant.

As the motor heats up, usually the viscosity decreases and the oil pressure goes down.

 

[beermak]

Re: Oil Pressure vs Oil Level

im always checking in the water the oil level. I see a decrease of less than 5 between hot and cold, so thats not making that big gap between having the oill filled to MAX and running several times and eating some oil in the process.

How do i check the "breather system" thats the hoses that run from the heads to the carb?

Im considering the real full mark will be between the MIN - MAX as from now considering the oil pressure which seems adecuate during its run time.

thanks to everyone!