1986 Ford F150 oil pressure loss

1986 FORD F-150
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SHERIFF310
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Engine Mechanical problem
1986 Ford F150 6 cyl Four Wheel Drive Manual 255 K miles
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Good evening. Last week I experienced an oil pressure loss. My 4.9L oil pressure used to run 50 PSI at 2300 RPM's and 22 PSI at idle while operating at normal operating temperature. Now, my pressure is fine when cold, its around 56 PSI when cold and after engine warms up, it drops to 34 PSI at 2300 RPM and 12 PSI at idle. Oil level is normal and the only other issue that occured at the same time the oil pressure dropped was the front main seal in the timing cover blew out. I had all gaskets replaced last year due to old age and leaks. The front seal was also changed at the same time. Could this be the problem why my pressure all of a sudden dropped?
Feb 25, 2008 at 7:11 PM
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RASMATAZ
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Do an actual oil pressure check with a mechanical gauge if its normal and no weird knocking noises replace the oil pressure switch-might want to do an engine flush.
Feb 25, 2008 at 7:27 PM
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SHERIFF310
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[quote:378e07ec5c="rasmataz"]Do an actual oil pressure check with a mechanical gauge if its normal and no weird knocking noises replace the oil pressure switch-might want to do an engine flush.[/quote:378e07ec5c]


I forgot to add I use AutoMeter Sport Comp mechanical gauges. I am the original owner of vehicle. Oil has been changed every 3000 miles like clock work. I even went thru the effort to replace gauge thinking it may be bad. Still reads the same.
Feb 25, 2008 at 7:42 PM
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RASMATAZ
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For me your oil pressure is okay
Feb 25, 2008 at 8:15 PM
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SHERIFF310
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[quote:d4a7567b51="rasmataz"]For me your oil pressure is okay[/quote:d4a7567b51]

Thanks for your replies. Do you have any ideas why my pressure dropped so much in such a short time? I know things don't last forever but in your opinion main bearings starting to go?
Feb 25, 2008 at 8:24 PM
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RASMATAZ
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Could be a sloppy oil pump/cam/rod/main bearings-
Feb 25, 2008 at 9:29 PM
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SHERIFF310
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[quote:23cb591a03="rasmataz"]Could be a sloppy oil pump/cam/rod/main bearings-[/quote:23cb591a03]


I am going to fix the front main seal and switch from 10w40 to either 20w50 or straight sae 30 and see how long she will go.
Feb 26, 2008 at 11:10 AM