oil pressure, problem?
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Posting Guru
Joined: Nov 2003
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From: Concord, New Hampshire
oil pressure, problem?
Ok this is a new problem i have incountered with my 87 f-150, 4x4 351. i wqas crusing down the highway today 70-75 mph and got to the end of the highway, got off and at the stop sign, the oil pressure was jumping around a bit but slowly moving down twards none. but as soon as you give it a little gas it comes out of it, so i was thinking OIL CHANGE, so i did an oil change, only like 400 miles over, and the truck still does it, but if your driving back roads and come to a stop it dosent do this, any ideas, anyone ever had this problem, its gonna get a new oil pump in the spring, sence im in need of an oil pan gasket and pan, but im hoping this isnt serious. thanks, jeremy
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Joined: Feb 2004
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From: NORTHERN NH
MINES DOING IT ITS A 92 F150 302 AUTO 4X4, I REPLACED THE OIL PAN PUMP AND ROD BEARINGS A COUPLE OF MONTHS AGO BUT THE OTHER DAY THE OIL PRESURE GUAGE IS DOING THE SAME. I THINK THE OIL SENDING UNIT ON MY IS GOING, BUT I HAVEN'T HAD TIME TO DIAG IT YET.
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Joined: Dec 2003
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This may or may not help your oil pressure problem but it solved mine. I purchased a 91 F150 with a 302, 167,000 miles. Oil pressure gauge showed approximately 1/2 scale - Normal, when driving or idling, until I changed oil.
After changing oil I would drive it about 5 miles and when I stopped and idled the gauge would drop into the read - Low Pressure. If would increase the idle speed from 700 to 850 rpm the pressure would again jump back to normal.
I recalled that when I changed the filter the holes in the new Fram filter were much smaller than in the Wal-Mart filter that was on the truck. I did some research on line and found some articles about oil pressure problems in high mileage vehicles when using a filter, such as Fram with small output holes.
To make a long story short I replaced the oil filter with a MotoCraft having large slotted output holes and the problem totally went away.
After changing oil I would drive it about 5 miles and when I stopped and idled the gauge would drop into the read - Low Pressure. If would increase the idle speed from 700 to 850 rpm the pressure would again jump back to normal.
I recalled that when I changed the filter the holes in the new Fram filter were much smaller than in the Wal-Mart filter that was on the truck. I did some research on line and found some articles about oil pressure problems in high mileage vehicles when using a filter, such as Fram with small output holes.
To make a long story short I replaced the oil filter with a MotoCraft having large slotted output holes and the problem totally went away.
Post Fiend
Joined: Oct 2003
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From: New Jersey
There could be a lot of reasons for fluctuating oil gauges for mechanical reasons... the filter not flowing enough, the pressure spring in the oil pump housing being worn and less "springy", the pump itself being worn, bearings worn a bit, oil galley holes plugged, and the list goes on.
Add to that list the reality that Ford oil pressure gauges are just sad, well, it doesn't help.
For example, my 188K mile F350 crewcab has a 5.8L in it, and with that mileage I was worried that the oil pressure gauge sits between the left end of the scale and the "N" in Normal when cold, then drifts left a hair when the truck warms up.
Anyway, with a mechanical oil pressure gauge, I have 25lbs of pressure at warm idle, and 40-something at highway speeds even though the ford gauge displays essentially no pressure.
25 and 45 is way too low BTW, but then again, this 5.8L does have 188K of miles on it lugging around a 7,000lb crewcab, so its not a new motor at all.
Add to that list the reality that Ford oil pressure gauges are just sad, well, it doesn't help.
For example, my 188K mile F350 crewcab has a 5.8L in it, and with that mileage I was worried that the oil pressure gauge sits between the left end of the scale and the "N" in Normal when cold, then drifts left a hair when the truck warms up.
Anyway, with a mechanical oil pressure gauge, I have 25lbs of pressure at warm idle, and 40-something at highway speeds even though the ford gauge displays essentially no pressure.
25 and 45 is way too low BTW, but then again, this 5.8L does have 188K of miles on it lugging around a 7,000lb crewcab, so its not a new motor at all.
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Thread Starter
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Posting Guru
Joined: Nov 2003
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From: Concord, New Hampshire
Well for the oil filter thing, i run the best i run wix, for everything, now i know everyone is gonna comment on them but i personaly like wix the best, they seem to me to be better quality than fram and all of them and in my own opinion better than motorcraft, there bigger and that means more filetering surface area
And on the guage i was told that ford put some Resistor?? on the guage to keep them from jumping around and mine could be burnt out therefore giving me a more accurate reading? dose tthis sound right? thanks for the help everybody.
And on the guage i was told that ford put some Resistor?? on the guage to keep them from jumping around and mine could be burnt out therefore giving me a more accurate reading? dose tthis sound right? thanks for the help everybody.
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Joined: Jan 2004
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Just got done test driving it after I changed the sending unit. Crazy thing is still doing the same thing. Only have 30k on engine since it was rebuilt. I'm running out of things to, replace begining to think it time to replace the whole truck.