Oil pressure problem
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Oil pressure problem
Good Morning All
I have a 1990 F250, with a 351 in it. It has been leaking some oil now for awhile from the oil pan above the starter motor.
I noticed that on the idiot light, the pressure would drop so I installed a mechanical gauge. I have 20W x 50 wt oil in the engine right now.
When I first start it, cold, the oil pressure is 50. As i let the engine run and it heats up, the engine idles at 20. When I take it out of park and in drive, sit there as if stopped at a light the pressure drops to 15, rev the engine to 2000RPM the pressure goes to about 20.
I am going to be replacing the oil gasket ... what else could be the cause of the low oil pressure .. oil pump? clogged screen ?
Thanks for the advice !
I have a 1990 F250, with a 351 in it. It has been leaking some oil now for awhile from the oil pan above the starter motor.
I noticed that on the idiot light, the pressure would drop so I installed a mechanical gauge. I have 20W x 50 wt oil in the engine right now.
When I first start it, cold, the oil pressure is 50. As i let the engine run and it heats up, the engine idles at 20. When I take it out of park and in drive, sit there as if stopped at a light the pressure drops to 15, rev the engine to 2000RPM the pressure goes to about 20.
I am going to be replacing the oil gasket ... what else could be the cause of the low oil pressure .. oil pump? clogged screen ?
Thanks for the advice !
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Joined: May 2004
Posts: 12,170
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From: The hills of No. Calif.
The gasket will only cause leakage, not oil pressure drop. Possible causes of low oil pressure are bad bearings, as you suggested a bad oil pump or gunked-up pickup screen, or even a restrictive el-cheapo oil filter. If you're already running 20W50 oil then you've done the first thing that most folks try.
When you have the pan off check everything mentioned above, including popping off a main cap and rod cap to check the bearings. If they're scored and copper is showing, that's most likely the cause of your problem. If that's the case you may be able to get away with putting in new bearings with the engine still in the truck. The mains aren't real easy to do, but it is possible. If the crank is badly out-of-round and/or deeply scored, I'm afraid new bearings won't help much, they'll just get eaten up rather quickly.
When you have the pan off check everything mentioned above, including popping off a main cap and rod cap to check the bearings. If they're scored and copper is showing, that's most likely the cause of your problem. If that's the case you may be able to get away with putting in new bearings with the engine still in the truck. The mains aren't real easy to do, but it is possible. If the crank is badly out-of-round and/or deeply scored, I'm afraid new bearings won't help much, they'll just get eaten up rather quickly.
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Originally Posted by Kemicalburns
what brand oil filter you using? buy some seafoam and run that thru the motor as well. how many miles on the motor, you might even do a compression test
As for the miles on the truck, the odometer says 15,100. Whether thats 115,100 or 215,100 .. who knows. I dont recall what the name of the oil filter was. I know its not FRAM. Its blue. When I bought it the guy at the parts store said it was a good quality oil filter.
What is seafoam ?
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Joined: Jan 2003
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From: Prairieville, Louisiana
Seafoam is a cleansing liquid that can be used in several ways. It can be put into your gas, oil, or through your vaccum systems. The instructions are on the bottle. Most auto parts stores carry it. It is definetly a good cleanser to use in a higher mileage motor.
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So am I correct in assuming that if you have good oil pressure when the engine starts, the oil pump is doing its job and the low pressure after the oil warms is due to some other problem (ie bearings) ?
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Joined: Jan 2004
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From: Troy,NY
Originally Posted by dm4432
So am I correct in assuming that if you have good oil pressure when the engine starts, the oil pump is doing its job and the low pressure after the oil warms is due to some other problem (ie bearings) ?
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From: Phoenix
i would run seafoam in there i did that in my 289 cause when i bought my mustang it sat for 3.5 yrs and it cleaned it mighty good then after i drained all the oil and let it sit for a few i got some rislone cause its basically detergent then after that my oild pressure went up quite a bit