low oil pressure
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Joined: Jun 2003
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From: bristol, tn
low oil pressure
i just put a high volume oil pump in my 302 because the old one i got 5 psi at idle when up to temp and i still have that same pressure at idle but now when you give it gas the oil will react more than it did before. is this something that i should worry about or try to get fixed in a hurry! its a rebuilt motor and only has 17240 miles on it.
Senior User
Joined: May 2002
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From: Denver
low oil pressure
Sounds like a sender unit problem, but don't buy one untill you know you need one.
You need to do a pressure test with a known good guage, this is done by teeing at the oil pressure sender. If you don't have one then now would be a great time to invest in a good on. I bought a set on the tool truck for about $65, but it included a tranny pressure guage. You could get a cheep one for $15-$20 at an auto parts store, or you could buy a new sender unit for less?
Robert
72 F100 Ranger XLT W/86 5.0L EFI W/ AOD
www.geocities.com/krazdndenver
You need to do a pressure test with a known good guage, this is done by teeing at the oil pressure sender. If you don't have one then now would be a great time to invest in a good on. I bought a set on the tool truck for about $65, but it included a tranny pressure guage. You could get a cheep one for $15-$20 at an auto parts store, or you could buy a new sender unit for less?
Robert
72 F100 Ranger XLT W/86 5.0L EFI W/ AOD
www.geocities.com/krazdndenver
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Joined: Jul 2003
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From: Bothell, WA
low oil pressure
I realize this may smell of snake oil, but my hot idle oil pressure jumped about 10 PSI just by switching from a Fram to a NAPA oil filter. This was on a remanufactured motor with about 50 miles on it.
You don't mention what weight of oil you are running?
Kevin
You don't mention what weight of oil you are running?
Kevin
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Joined: Jan 2002
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From: Tucson
low oil pressure
Like jds said, the low oil pressure is a bearing issue. My 352, when hot, idles at about 7. The highest reading (cold engine acclerating) is about 40. I wouldn't worry about it.
jor
jor
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From: bristol, tn
low oil pressure
i'm am running castrol full synthetic 10w30 motor oil. also my gauges are mechanical so i don't really have a sender. you can hear a bassy kind of thud sound or something. also when i drive for a few hours the oil pressure when in gear will get bellow 5 psi. i've asked around about it and found out that they seem to think that my main bearings might have too much tollerance.
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Joined: Feb 2000
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From: Brea CA
low oil pressure
My 5.0 sounded like that, it was main bearings. You could really hear it thump right after a oil change before it built up pressure.
Barry
Barry
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From: nevada
low oil pressure
If you go to a 10-40, your pressure rise a little. I live in the desert where the temps are presently over 110 degrees. The Valvoline tech line guy told me to run 20-50 in the summer here. My cold pressure is around 55 and 15-20 at idle. In the winter I use 10-40, where temps usually never go below freezing. Currently 5000m on last yrs rebuild.
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Joined: May 2003
Posts: 520
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From: california
low oil pressure
High volume and high pressure are two different types of oil pumps. A high volume oil pump will not increase oil pressure. At idle, my oil guage reads 20PSI and 40PSI at higher rpms. I installed a manual oil guage (vs. electric). My machinists says that as long as FE's have oil pressure, don't worry. But I'd be concerned with only 17240 miles on the motor.
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Joined: Jul 2003
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From: Bend, OR.
low oil pressure
I have been running SBF's for years and would never continue to run it with that low of OP. It sounds like you definately have bad main bearings, and possibly the crank is bad now. Bad main bearings will give you both the low OP and the knock sound. When it was rebuilt did they grind the crank?
The good news is that if the motor only has 17K on it then the rest is likely fine. I'd pull it and have the crank ground to the next undersize, and replace the main bearings to suit.
The good news is that if the motor only has 17K on it then the rest is likely fine. I'd pull it and have the crank ground to the next undersize, and replace the main bearings to suit.
Last edited by whisperer; Jul 12, 2003 at 12:33 AM.
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From: bristol, tn
low oil pressure
could the motor that was reved too high cause the low oil pressure, high enough to float the valves and pull the studs out of the heads. i just put 2 and 2 together and remembered that a car delership ran my truck to 50 in first gear during a speedometer test cause they tought they had it in 3rd gear but they had it in 1st but i didn't think it did any thing else to the motor besides the heads. but now i think this is the cause of my low oil pressure. they might have some how lossened my main bearings by doing this. could this be a problem w/ the people that built the motor or has this happened before? thanks for all the help so far.