So my brother took me for a ride in his 03 GMC Sierra with the 5.3 the other day, and when he floored it, it would peg the oil pressure gauge (at about 5500 rpm)
My oil pressure gauge moves very little if any... it hits half when i start it, and stays there till i shut it off.
So is this how your Hemis are?
Anyone know why my bro's truck pegs the gauge?

 

Bad GM ground, which is pretty common. It could also be a bad sending unit. On the Obama Motors truck.
Yours may be a dummy gauge that reads about 1/2 as long as you have over 7psi of pressure.
My 08 goes up to almost 3/4 when cold and at higher rpm and at a hot idle about 3/8. It works as a real gauge.

 

so the problem is with his truck, not mine? i thought that 5.3 was gunna start spraying oil with all that pressure. lol.
maybe mine is a dummy gauge... anyway to check?

 

Yours is an 03 like mine. Dodge use a dummy type gauge in our trucks.
If it's got oil pressure, it'll read a lil' past halfway.
Mine has always been like this.
Al.

 

Just outta curiousity, what psi was it showing when it was pegged?

 

I know the GM's usually hold about 40psi Hot. Up to 62psi cold.
We used to have a Chevy Astro van years ago. It always read 80psi until I put a new sending unit in it, then it stayed between 25 and 40 like it should.

 

Dodge's oil pressure gauges are Dummy gauges. They sit in the middle and look pretty.

 

Mine doesn't!!