Oil Pressure Problem 370/Help !!!!

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May 30, 2008 | 01:13 AM

Oldmics

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Oil Pressure Problem 370/Help !!!!

Gentlemen

Oil pressure problem that I need some advice on.

Vehicle is a 79 F 700,24 foot box truck with a rebuilt 370 engine.

I installed a rebuilt engine years ago but it has probably less than 30,000 miles on it.

Always kept the oil changed-good maintaince but it always carrys heavy loads.

Recently on startup the gauge (original) exhibits good normal oil pressure.

After warmup at idle it has really low oil pressure according to the gauge.

I have noticed that on hard turns such as a cloverleaf ramp on an interstate the gauge will go low and I can hear lifter/rocker noise so there is definatly low oil pressure.

I believe the gauge to still be accurate.

Pulled the pan off and its clean as a whistle.I"m gonna replace the oil pump while the pan is off but I dont see any problem.

What do you think is the problem?-Cam bearings worn causing low pressure?

Oldmics

May 30, 2008 | 11:23 PM

3Mike6

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From: Oakdale,Ca.

Suggest plugging in with a good mech gauge before you pull it apart.

May 31, 2008 | 12:54 AM

Bear 45/70

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From: Union, Washington

Could be a bad pressure relief valve. When cold the oil is dense enough to keep pressure up, but once warm, no. What weight oil you running? Straight weights don't do this temp crap and I why in my truck motors I run straight weights.

May 31, 2008 | 06:03 AM

werneil

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hi, bad oil pressure when hot might mean lots of things, but oil pressure drop when cornering means oil surge away from the pick-up for whatever reason, low oil, damaged
sump ???. oil pressure if no major faults are found maybe a higher weight oil is needed
in australia we can use up to 40w/70 on older style motors and i'am not talking about old
worn out motors

May 31, 2008 | 11:20 PM

Oldmics

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Bear

What is a "pressure relief valve"?

Is it in the oil pump?

As I said I am putting a pump on it anyways to see what happens.

I have always used 15-40 oil in the engine.

Werneil-I agree with your assesment of around corners its sucking air.

No damange to the pan,pickup tube and the screen was perfectly clear.

I did find gaskets on where the pump joins to the engine block and also on the pickup tube where it attachs to the pump.

According to Ford they should not have gaskets in these positions.

Perhaps that is the sucking air problem.

I"m putting it together tomorrow and we shall see.

Any additional thoughts welcomed and thanks to you gentlemen for the replys.

Oldmics

Jun 1, 2008 | 12:29 AM

Bear 45/70

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From: Union, Washington

Pressure relief valve is in the pump.

Jun 1, 2008 | 08:02 AM

werneil

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please use the gaskets in your oil pump/pickup instalation, they are there for a reason
just make sure they line up properly with holes etc. no gaskets used by FORD ????
are you sure