oil pressure drops after warm up

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alan l

New Member

Jul 1, 2010

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md

Aug 13, 2010

#1

• Aug 13, 2010

• #1

My 351C oil pressure reads 45psi at idle on start ups, but after about 5 minutes drops to 20psi or lower. I have documentation of new piston from a past owner. Do I need to up grade to high flow oil pump or/and crank bearing? Also car has been sitting for years and must pour gas into barb for 1st start.

 

horseballz

10 Year Member

Sep 30, 2009

824

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49

Las Vegas, NV

Aug 13, 2010

#2

• Aug 13, 2010

• #2

alan,
Have you changed the oil? Flushed the fuel system? If you started it after sitting "for years" without first filling cylinders with lube, priming the oil system and several other "must do" items, I really hope that you will be lucky to not have pooched the rings, cylinder walls, bearings, etc!
Good Luck,
Gene

 

2

2+2GT

10 Year Member

Apr 25, 2009

3,333

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79

Southeastern Pennsylvania

Aug 13, 2010

#3

• Aug 13, 2010

• #3

alan l said:

My 351C oil pressure reads 45psi at idle on start ups, but after about 5 minutes drops to 20psi or lower.

Click to expand...

And?

Hot pressure at 2000 rpm should be 35-55 psi. Try this and get back to us.

 

P

Pony66

New Member

Jul 23, 2010

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Aug 14, 2010

#4

• Aug 14, 2010

• #4

Im no expert, but it sounds like you need main bearings. I have heard horror stories about high flow oil pumps. Hopefullly we will get some posts from others with more experience.

 

2

2+2GT

10 Year Member

Apr 25, 2009

3,333

10

79

Southeastern Pennsylvania

Aug 14, 2010

#5

• Aug 14, 2010

• #5

Pony66 said:

Im no expert, but it sounds like you need main bearings. I have heard horror stories about high flow oil pumps. Hopefullly we will get some posts from others with more experience.

Click to expand...

Well, my question about the proper psi check was highly valid, since 20psi at hot idle is actually not a problem. I have heard the stories about high volume pumps too, but my personal experience is I have put over 200,000 miles on one with no side effects.

 

95Vert383AOD

15 Year Member

Jun 10, 2008

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New Bedford, MA

Aug 14, 2010

#6

• Aug 14, 2010

• #6

What filter are you using? I had the same issue on my 351w until i stopped using Fram.