Oil Pressure problem
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Freshman User
Joined: Jan 2004
Posts: 43
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Oil Pressure problem
Hi all,
I was having pressure issues on my 302 BRONCO, so I installed a new sending unit, new oil pump, Motorcraft filter and 15W -40 oil. The pressure wtill was acting crazy so I installed a mechanical oil gauge. The way it is acting REALLY worries me. When I start it up it will hold at about 40-45 PSI. then after I have been driving it will stay at 7-9 psi @ 2500 RPM and all the way down to what must be 1 - .5 psi when idling. however I do not here any clacking at idle it sounds fine.
Last bit of information, if I am ont he highway or going around 40 and hit the brakes fairly hard the pressure will actually increase by about 5 psi for a econd or two and then come back down.
Lastly the motor came with the truck and is out of a mid 90's truck we believe at thsi point so I I do not knw how many miles are on it...serpentine belt 302...
Any ideas?
I was having pressure issues on my 302 BRONCO, so I installed a new sending unit, new oil pump, Motorcraft filter and 15W -40 oil. The pressure wtill was acting crazy so I installed a mechanical oil gauge. The way it is acting REALLY worries me. When I start it up it will hold at about 40-45 PSI. then after I have been driving it will stay at 7-9 psi @ 2500 RPM and all the way down to what must be 1 - .5 psi when idling. however I do not here any clacking at idle it sounds fine.
Last bit of information, if I am ont he highway or going around 40 and hit the brakes fairly hard the pressure will actually increase by about 5 psi for a econd or two and then come back down.
Lastly the motor came with the truck and is out of a mid 90's truck we believe at thsi point so I I do not knw how many miles are on it...serpentine belt 302...
Any ideas?
Post Fiend
Joined: Jan 2000
Posts: 5,860
Likes: 4
From: Metro Detroit (Redford)
Sounds like a small leak somewhere between the oil level in the pan and the oil pump. Here is my hypothesis: When cold the oil is thick, so the minor air leak in the pickup does not affect it much, but once the oil is hot and thinner that air leak becomes very significant. Presumably the oil pickup and pump are forward in the pan and when you brake hard the oil pool slops forward, covering the air leak, thereby bringing pressure back up for an instant.
Possibly could test by adding a quart or so too much oil (maybe 1 to 1.5 inches up stick) to see if you can cover the leak. Don't drive that way but if the pressure goes up, then it may verify my hypo.
Last and a wild shot. Maybe front main bearing bleeding oil and when stop pool covers that.
Possibly could test by adding a quart or so too much oil (maybe 1 to 1.5 inches up stick) to see if you can cover the leak. Don't drive that way but if the pressure goes up, then it may verify my hypo.
Last and a wild shot. Maybe front main bearing bleeding oil and when stop pool covers that.
