Oil puddle and/or leak

2 questions.
1) Is the oil actually low on the dipstick?
If it is, you might have an oil leak, so you would need to look underneath and see. Also look for puddles when you park.
The most common reason for such consumption would be a burst oil pressure switch, or a leaking valve cover gasket.
Either of these will leak lots of oil.
The last possible reasons, which are really rare, would be engine parts defective,( like oil rings), or a leak in the brake booster which would suck oil from the crankcase into the brake booster.
2) If the oil is not leaking out, and the dipstick shows full, you will be needing a new oil pressure switch, or to have the electronics repaired.
God bless your efforts.

what was entailed in the rebuild?
cylinders bored and hone , new pistons , rings
crank grind and new bearings
or was it just a ring refresh and sand paper on the cylinders
I'm thinking the latter ( cheap and nasty)
The oil will be coming past the rings and being burnt in the exhaust ( cat converter if you still have one )
That oil passing the rings comes from , glazed bores , rings being installed upside down, ring gaps not being set 120 degrees apart but almost lining up
worn ring lands in the pistons
Sump oil either leaks out -- Gaskets , seals filters or is passed by the rings and burnt in the combustion process

Value guides are bad

The pressure relief valve is built into the oil pump. What you must do is have the area around the leak cleaned of all oil and dirt, then get under the car and try to see when the oil leaks where it seems to come from, I think the sending unit is around there for the oil pressure, it may be the problem, but do the cleaning 1st.

It is a possibility that the leak may come from bad seals from the water pump or a bad water pump. If you also observe bubble in the coolant inside the radiator when the car is running or water coming out of the exhaust you may have a bad head gasket. The coolant comes out of the bad part of the head gasket near the outside which lets water outside the engine as well.

change the hoses , you don't want this going out on your trip ,, if its just a small puddle did you miss when filling it up ? start the car and see if while turning it, it blows out a lot faster, if so thats the high pressure hose,, if it leaks a little thats the return line

On the 8 cylinder motors, the gaskets between the waterpump and block fail quite often. if you find it's the problem, get the new up-dated gaskets from a GM dealer- they are the only one's that have a decent replacement- costs less then aftermarket too!

I would say you have a leak, either the oil pan plug or the valve seals or the rings, the rocker cover gaskets could be leaking, they usually leak out the rear and soak the header pipe, does it smoke under the hood when you start it? Does it leave a puddle on the ground? How about blue smoke when it is stepped on? A compression check will tell you about the rings. If you park in the dirt or someplace where you can't see a puddle, put a piece of cardboard under there.Check it out.

You need to find the source of the leak. it hasn't overheated yet because you keep catching it and re-filling. From your description, it sounds a lot like a bad water pump seal (part of pump) but without physically looking you can't be sure of that. when the pump seal begins to fail, internal pressure while running often will drive the seal tighter against the shaft stopping the leak. as pressure drops as the engine cools, the seal relaxes and permits seepage.
With time, that will change and it will leak all the time.

- 20mm wrench $12
- new power steering pressure line found only at dealership $80
- experience priceless