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Low oil pressure

I just replaced my head gaskets, studs, injectors, glow plugs, egr delete, and oil cooler. When i wentto start the engine the first couple times it cranked forever before starting. This went away as soon as i drove it for a few miles. The other day i went to start the truck and it died imediatly, retried and it started and ran fine. Now it starts hard and once it is running oil pressure is normal, until it gets to below 700 rpm the the gage drops to noting. As soon as i get the rpm's above 700 it returns to normal???????? any help?
 

blacksnapon

Moderator
Staff member
That will probably be the sending unit. If the 6.0 loses oil pressure, it wont run.
 
When i come to a stop, the pressure gauge drops all the way down and the check gauge light comes on. I can sit through a light and when i get the rpm's up the gauge goes up to normal. It only starts hard.
 

d-kuzmen

Master Ford Tech
2,109
79
Connecticut
I agree I would replace the oil sender seen bunch of them go bad. Again if the 6.0 were to loose oil psi it would shut off. As for your hard start you may have a high pressure oil leak someplace. Recomend air testing through the ICP sensor port, you will also have to turn the ipr on and then listen for a air leak either under the valve covers or at the rear of the engine where the high psi pump is.
 
I replaced the oil sending unit and still have the same issue. When i went to start the engine it cranked over for 55 seconds before it started, once it starts it stays running. When the engine rpm gets below 1200 rpm the oil pressure gauge drops to zero, once i get the rpm's above 1250 rpm it goes back to normal. I feel it is either a low oil pressure pump, or a air leak in the high pressure side.
 

blacksnapon

Moderator
Staff member
what kind of oil filter do you use? The ones with the cap built on to the filter can cause a low oil pressure issue.
 

d-kuzmen

Master Ford Tech
2,109
79
Connecticut
I replaced the oil sending unit and still have the same issue. When i went to start the engine it cranked over for 55 seconds before it started, once it starts it stays running. When the engine rpm gets below 1200 rpm the oil pressure gauge drops to zero, once i get the rpm's above 1250 rpm it goes back to normal. I feel it is either a low oil pressure pump, or a air leak in the high pressure side.

Did you find the problem yet?
 

Beachbumcook

Kansas Chapter member
make sure you have an OEM oil filter cap and an OEM oil filter. Will-fit caps and filters will allow the drain valve to remain open and the oil that is to stay in the oil filter housing drains out... so your motor is starved for oil until the oil filter housing fills back up.
 

d-kuzmen

Master Ford Tech
2,109
79
Connecticut
make sure you have an OEM oil filter cap and an OEM oil filter. Will-fit caps and filters will allow the drain valve to remain open and the oil that is to stay in the oil filter housing drains out... so your motor is starved for oil until the oil filter housing fills back up.

And think how much oil accually gets filtered with that valve open. I have changed some filters that have been installed for 5000 miles but looks like they have 10 miles on them.
 
i replaced the oil filter and cap with OEM parts and i still have the same issues. What is the oil pressure on the low side suppose to be? How do i test for a high pressure leak?
 

d-kuzmen

Master Ford Tech
2,109
79
Connecticut
Between 40 and 100 psi is good depending on engine temp and rpms. To air test you must remove the ICP sensor from the right side valve cover and apply around 60 to 80 psi of air pressure at the same time you need to turn the ipr solinoid on. then you listen for air leaks under the valve covers and at the rear of the engine.
 
well i was reading about issues others were having and while i was driving my truck sputtered then the check gauge light came on . the truck would not restart after that. i had it towed . i replaced the oil pressure sensor and the oil temp. sensor is fine. any suggestions????
 
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