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Hello all and I apologize if this issue I am having has been answered before. I can’t find my particular issue discussed on google :( Oil is full and is Motorcraft 5w-20 with a Motorcraft oil filter. Wiring to the autometer gauge is

I have a 97 GT and hooked up a autometer oil pressure gauge to know where I am at. The motor is a 4.6 2v and has PI heads, blower cams and was rebuilt 2k miles ago. Oil pressure is 70-80psi on cold start and I never lose it or see it drastically change. When nice and hot, I am idling with 20-25 psi. Once i bump the throttle it shoots to 50 psi. When I accelerate hard from a stop I see a nice gradual climb with pressure all the way to 60-70 psi. When I am driving on the highway is when I notice a slight fluctuation. When I am going 70-75mph in 5th gear at about 2200 rpm I noticed the meter was at 50 psi. I give it throttle and the needle will drop slightly down to about 45 psi and once I let off the throttle it will jump back to 50 psi. When I am at the same speeds and drop it into 3rd and accelerate the pressure goes to 55 and doesn’t climb as quick as it does when I am messing around in town. This is my first time having a aftermarket oil pressure gauge so I may be just a little paranoid. Just wanted to hear yalls opinions and/or experiences. Am I crazy or what? Thanks in advance!


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US Air Force (retired)
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The general rule of thumb is a minimum 10 psi per 1000 rpm. From what you are reporting I don't see anything wrong. Oil is a lot thicker cold that is why a cold start has higher pressure. The oil isn't flowing yet. When the motor gets warmed up and the oil is flowing then the oil pressure goes down. There is nothing wrong with a hot idle of 20-25 psi. I don't think I've ever had a car that hit 70 psi but there nothing wrong with that either.
 

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Discussion Starter #3
The general rule of thumb is a minimum 10 psi per 1000 rpm. From what you are reporting I don't see anything wrong. Oil is a lot thicker cold that is why a cold start has higher pressure. The oil isn't flowing yet. When the motor gets warmed up and the oil is flowing then the oil pressure goes down. There is nothing wrong with a hot idle of 20-25 psi. I don't think I've ever had a car that hit 70 psi but there nothing wrong with that either.


Ya I was just curious on the fluctuation I see when I am at operating temp on the highway.


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Rent Asunder!
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I wouldn't stress it. A slight fluctuation isn't a concern. My old Bronco did that and it lived to see 297k miles.
 

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Discussion Starter #6
No issues there imo.
I see probably 80 PSI hot at high RPM, but this is on a forged 4.2 liter v6 stroker that is recommended to run 15w40.


Ya I figured I am just being paranoid. This is my first time watching an accurate oil pressure reading.


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Discussion Starter #7
Meh, this morning’s commute was crap. I was in traffic for 35 min bumper to bumper. I noticed that my oil pressure was telling me 12.5 at idle at times. When I finally got up to speed while in 5th gear i was at 40psi. I know that these readings are still in spec, but I hate how they keep getting lower :( I am going to change the oil after work today.


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