Lost Oil Preasure
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Freshman User
Joined: Feb 2004
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From: eldon mo
Lost Oil Preasure
I have an 87 ford f150 4x4 with a EFI 302 v8. The truck has 123,000 miles on it. After running 5 - 10 min., it loses oil preasure. The preasure starts out in the middle of the gauge at idle and gradualy drops off to no preasure at all. I can rave the engine and the preasure will rise accordingly then it drops off again. I installed a new oil pump and still have the exact same problem as when i started. The pickup tube had been cleaned out and the pan completly cleaned inside and out. I also left the pan off of the truck for two days so that i could get all of the old oil out. I also replaced the filter and put the original type motorcraft 10w-30 oil back in it. Any help that you can give me would be greatly appreciated.
Fleet Mechanic
Joined: Nov 2003
Posts: 1,372
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From: West Cornwall, CT
Factory pressure gages are not particularly accurate. I'd recommend that you confirm that you have an oil pressure problem before doing anything else. Hook up a mechanical gage and find the real story. The problem might be just the oil pressure sender.
If your pressure gage is accurace and oil pressure is low, it may be caused by worn bearings. I'd expect a 302 to go more than 123K before the bearings were worn that much.
Lou Braun
If your pressure gage is accurace and oil pressure is low, it may be caused by worn bearings. I'd expect a 302 to go more than 123K before the bearings were worn that much.
Lou Braun
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From: eldon mo
I tried a mechanical gauge, it starts out at 25 psi and drops to 5 psi after running five min. at idle. I think its time for a new motor or different truck. What do you guys think?
Elder User
Joined: Jan 2003
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If you want to go cheap, get a crank kit from Advance auto for about $215. .010 under w/ matched bearings (rod and mains). Have the engine pulled and install the new crank and bearings, it will be worth every dime. I have a 351W in my 88 4x4 that the same problem, 12,000 miles later no problems, 65 cold @idle, 30psi @ hot idle in park, 20-25 in gear, 45-55 running down the road and 65 flogging it hard. total price, $702.45 cheaper than a new motor and definitly cheaper than a new truck!
Good luck, does sound like the bearings are shot, though.
Good luck, does sound like the bearings are shot, though.
Junior User
Joined: Sep 2003
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From: Texas
You can usually buy a decent old truck for what it costs to rebuild the motor. On the other hand, if you rebuild it you know what you have. Five pounds of pressure is too low to keep driving it in my book.
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From: eldon mo
I talked to the dealer I bought the truck from, he agreed to run the truck through a car auction for me and locate me a different truck since i have only had this one three weeks. I guess it helps to work for the guy you are buying your ride from......lol 
I hate to give her up, but i can't see putting any more cash in it. I'll find a better one than I had at least. Thanks for all of your help.....
I hate to give her up, but i can't see putting any more cash in it. I'll find a better one than I had at least. Thanks for all of your help.....
