The other morning it was around 7-8 degrees. I cranked her up and everything sounded normal. After cleaning windshield, I climb in and check gauges light is on, and to my dismay I see the oil pressure is at nothing! Needless to say, I figuratively poo my pants and shut her off. I call my bro, as he is more experienced mechanically, and he suggests to restart and baby it until it gets up to operating temp. I reluctantly agree and putt down the road about 3 miles to a parking lot. It was warm, sounded normal, but still no pressure. So I shut it off again, wait a few seconds, restart, and the gauge pops up to the middle like normal. Motor sounds and feels fine, so I keep on as usual. This happened I think twice again in the very low temps, but then never has again.
So, wondering what is the culprit? Initially, I thought that maybe some oil passage (or whatever) leading to the sensor (or whatever it is) was clogged from the oil being cold and thick, taking a while to get flowing. But now that it isn't doing it in similar awful friggin temps, I'm not so sure. Thanks for any insight.

 

Oh, sorry, I'm referring to an 03 Hemi, by the way

 

if it sounds good it probably has oil pressure. It's not a real gauge anyway just a switch. It has two positions, off and middle. Probably just the cold weather and an old switch acting up.

 

If your oil pressure truly dropped to zero, your engine would be making a racket. Replace your oil pressure sender. Stick with the OE sender, not aftermarket. I just replaced mine for the second time (4.7L engine). Mine failed with 20 minutes of me performing a motor flush, so you can imagine all the thoughts that went through my head.... nope, it was the sender.

https://dodgeforum.com/forum/2nd-gen...sure-drop.html

 

how often do you change oil

 

With the 4.7, I went every 3k-5k miles to be on the safe side.

 

I've only had the truck for around 1500 miles. But, from what I've seen, the previous owner, who had it most of its life, didn't seem to keep it up well. It spent its last few years as a beater hunting truck and then finally sat for a couple years. So I immediately changed the oil, with a quart of Marvel mystery oil, and ran it around 500 miles, and changed it again.

 

Not sure who you're asking. I change mine every 7.5K.

 

I had an '03 I got from one of the guards at work. It lost oil pressure and it was LOUD! Trust me, if you really lost oil pressure, you'd hear it. He only put gas in it and drove it. I dropped the oil pan to find it and the oil pickup completely blocked with sludge.




I've never seen a modern engine this badly sludged. After cleaning, I got lucky and the engine ran smooth with little apparent damage. If you have a 2wd, the pan isn't too bad, at least on the 4.7, to drop. I didn't have to raise the engine.

I don't think this is your problem. I'll bet it's your sending unit. The Marvel then change may have cleaned some sludge out if you had it.

 

Poor thing. This was my 4.7 before it blew a head gasket and I got a 5.7