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| Low Oil Pressure? (Page 1/1) |
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Kitopher
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JUN 01, 03:14 AM
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1986 2.8L v6, 140k miles
Major leak coming out of old sending unit diaphragm.
Replaced with oem part from O'Reillys.
New unit reads <40psi at cold start and 20psi at idle and while driving, regardless of throttle input.
I've checked the electrical side of things by grounding the connector and all seems well there.
Harbor freight mechanical pressure gauge reads 50psi at cold start, then warm idle at 18-20psi. 40psi when revved to 2k rpm.
I figure the new sending unit is junk out of the box, will be returning it.
My question is do my oil pressure numbers seem right?
Most info I've found on here says 30-45psi is normal range for warm and 60psi for cold start, but some posters have said their car idles at 10-15psi with no issues.
I just want to know if I need to look at my pump or bearings or if 18psi warm idle is acceptable.
Thanks in advance.
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olejoedad
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JUN 01, 06:53 AM
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For an engine with 140K miles, your oil pressure is fine.
What type, brand and weight oil are you using?
Next oil change, use a quart of LUCAS oil stabilizer....
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Vintage-Nut
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JUN 01, 09:49 AM
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| quote | olejoedad:
Next oil change, use a quart of LUCAS oil stabilizer.... |
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I know that some members use oil additives, however in my opinion, any good quality oil does not need their formula "doctored".
See theogre link from a lube scientist:
------------------
Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles[This message has been edited by Vintage-Nut (edited 06-01-2024).]
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Kitopher
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JUN 01, 10:08 AM
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| quote | Originally posted by olejoedad:
For an engine with 140K miles, your oil pressure is fine.
What type, brand and weight oil are you using?
Next oil change, use a quart of LUCAS oil stabilizer.... |
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I did an oil change a couple weeks ago and car hasn't been run much since then.
It's got Penzoil High Mileage 5w-30 synthetic blend in it.
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olejoedad
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JUN 01, 10:29 AM
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| quote | Originally posted by Vintage-Nut:
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Opinions vary.
Most people change their oil before the additives start working anyway.
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Kitopher
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JUN 01, 05:58 PM
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Not sure if it's relevant info, but the car does also need to be timed... so the 18psi warm idle I referenced is at abt 1k rpm, not the standard 750 of a properly timed 2.8L
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theogre
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JUN 01, 06:19 PM
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"Harbor freight mechanical pressure gauge reads 50psi at cold start, then warm idle at 18-20psi. 40psi when revved to 2k rpm."
V6, VIN-9, 30-45 PSIG at all RPM
see https://web.archive.org/web...t/~fierocave/oil.htm
"50psi at cold start" is a bit high but not a huge problem.
But "warm idle at 18-20psi" is a problem & only get worse. Could be Pump Wear but "Fiero" V6 are known for low pressure because crank & cam bearing wear out cause low oil pressure. Same V6 was use by other FWD cars had same problem or just "blow an engine" because drivers ignore low pressure.
Low Oil Pressure will Not help by using any additives & drain your wallet. High oil pressure can by cause by additives or oil pump & other problems.
many put "high volume" etc pump on engine w/ bearing problems can cause OP High when cold & still get Low pressure when engine is hot.
Or Stock pumps can has same problem because regulation on then are "bad."
Gauge reading off...
Test new sender w/ Ω meter should see 0-90Ω from 1 pin to block.
see https://www.fiero.nl/forum/Forum2/HTML/146784.html Fuel, Engine Temp or Oil Pressure gauges have problems?
Do Not buy "Fat" sender that leak oil because new one does same often in 1 to 3 years. 88 sender can fail electrically but doesn't leak oil like "Fat" senders.
see https://web.archive.org/web...rocave/oilsender.htm------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
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