Oil Pressure

TexasViper35

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I’m seeing something new that is bothering me. The oil pressure at start up flies to 100psi and wants to stay around that. After the temp is warmed up it falls to 75-80psi at idle, but as soon as I start driving it goes back to 100psi. the oil and filter were changed about 1500-2000 miles ago, Viper filter and Mobile One; that was only 2-3 months ago. It’s done this yesterday and today, I’m wondering if I should be worried enough to change the oil and filter again, or just drive it a bit more. Thoughts (that won’t scare the **** out of me)?
 

Steve-Indy

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Document the oil pressure with a mechanical gauge. Sensors go bad...change as necessary. Whether or not you change sensor...you could easily change oil and filter. If the filter you used was not the Viper specific filter for your car (presuming it is a Gen III...part number. 05037836AB...NEVER use the first version 05037836OAA) I would definitely change the filter. Our 03 pegs at 80 (top of the 03 gauge) on startup, then settles down to around 45-50 psi when fully warm, on a warm day, using Mobil 1's 0W-40.
 

cothrelo

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My 05 with a paxton starts off in the 80-90 range and once warmed up goes down to the 50ish range. Driving it will go back to the 70-80's. The sensor is not hard to get to. I was looking at mine because the temps were all over the place and at one point looked to be over heating. Come to find out the plug on the sensor had worked its way out on the plug and basically had a loose connection. reseated the plug and has been fine ever since. I do have a spare sensor just in case. The sensor OEM was about $80 if I remember correctly
 

MoparMap

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I've had my sensor go bad once in a really easy to spot way. When it failed it would show 25 psi with the key on and the engine not even running and carried that offset all the time, which gave me numbers very similar to what you are seeing. Yours might not be that extreme, but you could see if it shows anything noticeably more than 0 with the key on and engine off.
 
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TexasViper35

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I've had my sensor go bad once in a really easy to spot way. When it failed it would show 25 psi with the key on and the engine not even running and carried that offset all the time, which gave me numbers very similar to what you are seeing. Yours might not be that extreme, but you could see if it shows anything noticeably more than 0 with the key on and engine off.
Key on engine off it jumps to 50psi. Where is the sensor located?
 
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MoparMap

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Yeah, behind the bottom of the alternator. Not the easiest thing to get to, but shouldn't have to take anything apart. You will need a big socket for it though. I don't believe it was the typical rounded corner oil pressure socket style, but you will still need a deep set one to clear the connector body. I'd be careful when you remove the connector as well. On mine the locking block that holds the terminals in got stuck in the sensor. Easy enough to pop out with some pliers, but just good practice to check everything before putting the new one in.
 
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