Oil Pressure Varies, WTF?

xj220

Founding Member

Sep 15, 2000

696

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Dec 22, 2004

#1

• Dec 22, 2004

• #1

I noticed that when I idle for a bit or am at lower revs the oil pressure drops a bit (the needle points at the O in Oil on a 66 Gauge). When the revs go up though and I'm moving, the oil pressure goes back up again (to the L in Oil). Is this normal or is it the sign of something to come. We just got some engine work done (new heads) so it'd be nice to avoid more shop work, but I know oil systems are nothing to mess with. Any ideas?

 

R

Ronstang

New Member

Apr 4, 2004

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Houston Texas

Dec 22, 2004

#2

• Dec 22, 2004

• #2

It always did that on my old coupe and I put 120,000 miles on it that way so I assume it can't be that big of a deal.

 

krash kendall

Active Member

Nov 19, 2004

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Aldergrove, B.C. Canada

Dec 22, 2004

#3

• Dec 22, 2004

• #3

Is this a new problem that started after the work was done or did it always do this? Your awareness may have increased after the work so that you are noticing things you didn't before.

Does the pressure drop when you cut sharp corners (sloshing oil) as well? Do you ever hear the valve train tapping? Do you know the actual PSI?

A shop can hook up a master guage to get the pressure and give you a definite answer.

 

S

snowball

New Member

Dec 10, 2004

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Melbourne, Australia

Dec 22, 2004

#4

• Dec 22, 2004

• #4

Oil pressure should drop a bit when the engine is at idle or at low revs. Under load or at higher revs pressure should return to normal higher readings on the guage. If it drops more than you have noticed before, it could be the type of oil you are using. A thinner oil can cause pressure to drop more than usual.

 

xj220

Founding Member

Sep 15, 2000

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Dec 22, 2004

#5

• Dec 22, 2004

• #5

I'm home on break right now so it could be something that's normally happening and I'm just not used to it. The engine sounds find at all times. One reason we got new heads was because the old ones were so damaged they were unrepairable. I'm wondering if some metal shavings would've gotten into the pan and clogged up the filter a bit. I was more just wondering if this sort of thing was common or if I should keep a heads up. Thanks.

 

D

darkhorse70

Founding Member

Dec 7, 2000

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Austin, TX

Dec 23, 2004

#6

• Dec 23, 2004

• #6

A drop in oil pressure over time generally indicates bearing wear. As the clearance between the bearing and crank journal increases, less back pressure is produced since the oil squirts through more easily. This is most noticeable at low revs. At higher revs the oil pump pumps more oil volume, which brings the pressure back up.

 

F

ForceFed70

That's why they call it "dope"

Founding Member

Dec 6, 1999

4,818

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69

BC Canada

Dec 23, 2004

#7

• Dec 23, 2004

• #7

That's somewhat normal. You'll also find that the pressure is higher when the engine is cold and the oil is thicker.

Just so long as it doesn't drop tooooo low.