Oil pressure drops
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Oil pressure drops
I have an '87 econoline van 4.9L. since I bought it about 5 years back the oil pressure reading was always above the N on normal. Lately it always starts out normal but after about 20-30 miles it suddenly drops completely down. At the point it drops it still runs good for several more miles before it seems to start running a little rough. If you then cut it off and let it sit for about 15 minutes it returns to normal and you can drive it several more miles before it drops. Any help would be appreciated.
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Pull your oil pressure sender and:
--replace with a real gauge & check oil pressure
--replace sender for existing gauge
--do both: plumb in a 'tee' and screw the sender into one side, a real gauge into the other. See if there is a real drop in OP that leads to poor running.
I'm not sure if you have a oil pressure kill switch for the fuel pump.
You can run the line for the gauge through the seal on your dog house temporarily. Just leave it loose enough so you don't crush the line.
BUT first, do you have lifter clacking with this 'rough running'?
--replace with a real gauge & check oil pressure
--replace sender for existing gauge
--do both: plumb in a 'tee' and screw the sender into one side, a real gauge into the other. See if there is a real drop in OP that leads to poor running.
I'm not sure if you have a oil pressure kill switch for the fuel pump.
You can run the line for the gauge through the seal on your dog house temporarily. Just leave it loose enough so you don't crush the line.
BUT first, do you have lifter clacking with this 'rough running'?
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Joined: Dec 2008
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Oil Pressure
Sounds like the bearings are worn and the pump can't maintain oil pressure as the oil warms up and gets thinner. It is an 87 and probably has some miles on it. Since you were not the original owner, you can't know how well (or not) it was maintained over the years. Frequent oil changes,
with filters prolong engine life.
with filters prolong engine life.
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Joined: Dec 2005
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Ya, what Badge1 said. The factory guage is nothing more then a dummy light, it reads pressure above a certain pressure (never have gotten a concise answer what pressure that is) and once it is below that pressure, the guage reads no/very little pressure. On my 88 Bronco 302 it did what you are describing and I didn't know what I know now. I drove it that way for a few months before I was 200 miles from home and broke my crankshaft from low oil pressure. I'm not saying that's definately what you have, but you need to get an actual, functional guage on it to determine exactly what it is doing and then go from there.
MoMo
MoMo
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