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Topic: no oil pressure at high rpms (Read 2226 times) previous topic - next topic

no oil pressure at high rpms

My friend has an F-250 with a 5.0. with 250,000 miles. He looses oil pressure after the motor warms up at high rpms.( like when he passes someone on the highway). He had the pump, pick up tube and pan replaced new a year and a half ago. It did it back then before the replacement parts also. any ideas? bad pump? sludge? something else?

Jerry
[SIGPIC][/SIGPIC]
***** Project "EVOLUTION" 1987 Cougar LS  & 1985 Cougar Convertible *****
[/COLOR]
5.0 HO 306 roller block, machined GT-40P heads, Wiseco dished forged pistons, Eagle forged floating I-beam connecting rods, Lunati pushrods, ARP bolts, Scorpion aluminum 1.6 rockers, Comp Cams Magnum 266HR, Explorer intake, 65mm TB, MAF Conversion, 19# injectors, Ford Racing stainless P-headers, 2-1/2" cat-less exhaust w/ Flowtech Afterburner lers , SC AOD with 2800 BDR torque converter, 3.73 T-Lok rear, CHE rear control arms, full 2-1/2" frame w/1" jacking rails & seat supports, Rear disk brakes, Turbine wheels, All original interior w/ floor shift upgrade .......
Pretty much every panel on my 87 is new, rebuilt, or re constructed. :D
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no oil pressure at high rpms

Reply #1 –
sounds like somethings blocking the sending unit. that motor wouldn't last long with no oil pressure at 3500 rpms.
1979 Ford Fairmont
[/B]
5.0L/4R70W/8.8"/5-lug/3" Exhuast

no oil pressure at high rpms

Reply #2 –
Time to hook up a true mechanical gauge and go for a drive......
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

no oil pressure at high rpms

Reply #3 –
The gauge is working properly. He has to shut it down because the engine isn't circulating oil and starts to tic.
[SIGPIC][/SIGPIC]
***** Project "EVOLUTION" 1987 Cougar LS  & 1985 Cougar Convertible *****
[/COLOR]
5.0 HO 306 roller block, machined GT-40P heads, Wiseco dished forged pistons, Eagle forged floating I-beam connecting rods, Lunati pushrods, ARP bolts, Scorpion aluminum 1.6 rockers, Comp Cams Magnum 266HR, Explorer intake, 65mm TB, MAF Conversion, 19# injectors, Ford Racing stainless P-headers, 2-1/2" cat-less exhaust w/ Flowtech Afterburner lers , SC AOD with 2800 BDR torque converter, 3.73 T-Lok rear, CHE rear control arms, full 2-1/2" frame w/1" jacking rails & seat supports, Rear disk brakes, Turbine wheels, All original interior w/ floor shift upgrade .......
Pretty much every panel on my 87 is new, rebuilt, or re constructed. :D
Join us on Facebook
http://www.facebook.com/home.php?sk=group_137541156293768&ap=1

no oil pressure at high rpms

Reply #4 –
The last of the 318's they put in Dodge trucks would do something similar.  The lifters were usually the culprit.  Those held good pressure though when warm though......

If the cold pressure is within specs, this is sign of worn bearings......what weight oil is on it now?
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

no oil pressure at high rpms

Reply #5 –
pull the sending unit off. then pull the distibutor and re-prime the pump. if you don't see any oil coming out where the sending unit was then you have a bad pump. if it does come out you have a bad sender.
1979 Ford Fairmont
[/B]
5.0L/4R70W/8.8"/5-lug/3" Exhuast

no oil pressure at high rpms

Reply #6 –
BTW, my old dodge had an oil pressure issue, but was the reverse of your friends. I woul lose oil pressure at a warm idle. that was due to sludge. I did everything I could do to remove it, but the only remedy would be to have the block vatted.
1979 Ford Fairmont
[/B]
5.0L/4R70W/8.8"/5-lug/3" Exhuast

no oil pressure at high rpms

Reply #7 –
He's probably running 10w-30
[SIGPIC][/SIGPIC]
***** Project "EVOLUTION" 1987 Cougar LS  & 1985 Cougar Convertible *****
[/COLOR]
5.0 HO 306 roller block, machined GT-40P heads, Wiseco dished forged pistons, Eagle forged floating I-beam connecting rods, Lunati pushrods, ARP bolts, Scorpion aluminum 1.6 rockers, Comp Cams Magnum 266HR, Explorer intake, 65mm TB, MAF Conversion, 19# injectors, Ford Racing stainless P-headers, 2-1/2" cat-less exhaust w/ Flowtech Afterburner lers , SC AOD with 2800 BDR torque converter, 3.73 T-Lok rear, CHE rear control arms, full 2-1/2" frame w/1" jacking rails & seat supports, Rear disk brakes, Turbine wheels, All original interior w/ floor shift upgrade .......
Pretty much every panel on my 87 is new, rebuilt, or re constructed. :D
Join us on Facebook
http://www.facebook.com/home.php?sk=group_137541156293768&ap=1

no oil pressure at high rpms

Reply #8 –
he may be pumping all the oil up on the heads, and the oil return holes are clogged with sludge and letting the oil pan run dry.... pop the VC off and se the oil returns clear ...
1985 TC (yet another one) Fully loaded
has 225k mile  still with the factory head gasket






84  Turbo ranger  Daily driver  ($800.00 Ebay deal)
          volvo FMIC and more getto rigging than the law should allow

no oil pressure at high rpms

Reply #9 –
Quote from: BogusSVO;308833
he may be pumping all the oil up on the heads, and the oil return holes are clogged with sludge and letting the oil pan run dry.... pop the VC off and se the oil returns clear ...


He's going to check that first.
[SIGPIC][/SIGPIC]
***** Project "EVOLUTION" 1987 Cougar LS  & 1985 Cougar Convertible *****
[/COLOR]
5.0 HO 306 roller block, machined GT-40P heads, Wiseco dished forged pistons, Eagle forged floating I-beam connecting rods, Lunati pushrods, ARP bolts, Scorpion aluminum 1.6 rockers, Comp Cams Magnum 266HR, Explorer intake, 65mm TB, MAF Conversion, 19# injectors, Ford Racing stainless P-headers, 2-1/2" cat-less exhaust w/ Flowtech Afterburner lers , SC AOD with 2800 BDR torque converter, 3.73 T-Lok rear, CHE rear control arms, full 2-1/2" frame w/1" jacking rails & seat supports, Rear disk brakes, Turbine wheels, All original interior w/ floor shift upgrade .......
Pretty much every panel on my 87 is new, rebuilt, or re constructed. :D
Join us on Facebook
http://www.facebook.com/home.php?sk=group_137541156293768&ap=1

no oil pressure at high rpms

Reply #10 –
Can the oil pick-up move in a 5.0?  I had a small block chevy doing this once and the oil pick-up was pressed in and moved up highter (I think this happened when the pan was put on).  So it was not down as low it it should have been and staving for oil when the oil moved back under higher RPM.

I can of feel bad not knowing about 5.0 engines and being on this forum.

TED

no oil pressure at high rpms

Reply #11 –
5.0/302 has a bolt on pick up, yes the bolts could shake loose, also there are gaskets between the the pick up and pump, and the pump and the block.

if the pick up was loose, or the gaskets failing, he would not have oil pressure at any time, for it is easier for it to pump air than oil.
1985 TC (yet another one) Fully loaded
has 225k mile  still with the factory head gasket






84  Turbo ranger  Daily driver  ($800.00 Ebay deal)
          volvo FMIC and more getto rigging than the law should allow

no oil pressure at high rpms

Reply #12 –
High volume pump + stock size oil pan = potential for oil starvation.  Make sure it's FULL. 

I have an 8 quart pan & pickup awaiting install with Chucks mounts and some other goodies......
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

no oil pressure at high rpms

Reply #13 –
He does have a high volume pump that was put in last year.
[SIGPIC][/SIGPIC]
***** Project "EVOLUTION" 1987 Cougar LS  & 1985 Cougar Convertible *****
[/COLOR]
5.0 HO 306 roller block, machined GT-40P heads, Wiseco dished forged pistons, Eagle forged floating I-beam connecting rods, Lunati pushrods, ARP bolts, Scorpion aluminum 1.6 rockers, Comp Cams Magnum 266HR, Explorer intake, 65mm TB, MAF Conversion, 19# injectors, Ford Racing stainless P-headers, 2-1/2" cat-less exhaust w/ Flowtech Afterburner lers , SC AOD with 2800 BDR torque converter, 3.73 T-Lok rear, CHE rear control arms, full 2-1/2" frame w/1" jacking rails & seat supports, Rear disk brakes, Turbine wheels, All original interior w/ floor shift upgrade .......
Pretty much every panel on my 87 is new, rebuilt, or re constructed. :D
Join us on Facebook
http://www.facebook.com/home.php?sk=group_137541156293768&ap=1

no oil pressure at high rpms

Reply #14 –
then that's why he's losing pressure.
1979 Ford Fairmont
[/B]
5.0L/4R70W/8.8"/5-lug/3" Exhuast