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Discussion Starter #1
So I am currently using Valvoline Conventional 5w-20 oil in my 96 4.6L Thunderbird's engine. Ford, the owner's manual, and different owners I have spoken to all say use either 5w-20 or 5w-30 weight oil. I decided to use the 20 weight to maybe free up some horsepower but now my oil pressure is low. Not dangerously low as to cause problems, but just below the "n" on "norm" on the reading in the gauge cluster. Is this from the oil or from another issue? Thank you.
 

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My Chiltons says 10w30 or 5w30. The stock gauge isn't very accurate and varies car to car. I'm sure someone who knows oil better can give you some tips though.
 

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So I am currently using Valvoline Conventional 5w-20 oil in my 96 4.6L Thunderbird's engine. Ford, the owner's manual, and different owners I have spoken to all say use either 5w-20 or 5w-30 weight oil. I decided to use the 20 weight to maybe free up some horsepower but now my oil pressure is low. Not dangerously low as to cause problems, but just below the "n" on "norm" on the reading in the gauge cluster. Is this from the oil or from another issue? Thank you.
Unless you've modded the oil pressure system, it's irrevelent - it's a switch and a resistor, and the gauge will vary depending on several factors (including how many bean burritos you had for lunch, it seems ... )

The big secret is to put an accurate oil pressure gauge on it, and see if it's dropping too low at idle when warm.

RwP
 

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Yup if you're noticing the gauge reading differently it's either placebo effect from knowing you went to a different oil and are now paying closer attention, or you or whoever changed the oil bumped or soaked the connector on the sender with oil. Any varation between the center(between O and R) and nothing is circuit/connection related, the sender is nothing more than a pressure driven on/off switch.
 

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Discussion Starter #5
Thanks for the answers. I do tend to spill the oil out of the filter everytime I change it but if you've ever changed it on this car you know what I mean. Lol
 

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Sometimes my fake OP gauge will read a little low if I have a lot of electrical accessories running. So that might get someone thinking it's reading different.
 

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If you want to free up a few HP, just switch to a quality full synthetic and stick with what's required, 5W30. Change the oil weight at your own risk.
 

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Discussion Starter #8
Well we ran a cycle of synthetic 5w-30 through it and that's when I first noticed it dropped. I thought that might be it so i went back to conventional but it still runs a little low (or so it says). Sometimes it will jump up to the middle of "NORM" and then even run a little high. Then it will drop back to right on the "N." Go figure. It runs fine and isn't overheating or doing anything weird so I guess it's just a misreading.
 

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Well we ran a cycle of synthetic 5w-30 through it and that's when I first noticed it dropped. I thought that might be it so i went back to conventional but it still runs a little low (or so it says). Sometimes it will jump up to the middle of "NORM" and then even run a little high. Then it will drop back to right on the "N." Go figure. It runs fine and isn't overheating or doing anything weird so I guess it's just a misreading.
Search for the tech article showing how to convert it.
 
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