Long story short water pump went out and then took it to my guy which ended badly for me and im left still working on my truck after spending 700 to get it fixed. left dudes shop only for it to almost over heat in traffic.
i have only the top half of my fan shroud left over but i have changed the radiator water pump thermostat fan clutch and some hoses. ive done an entire days worth of flushing as well as a blue devil cleanse.
i got new coolant in and was at proper temps but there was a spike in temp and now there is oil in my radiator.
my mechanic also stated there was low compression in cylinder 2
any and all insight on this would be greatly appreciated

 

Sorry to hear about that...Id think the shop would have tested the vehicle...

The cooling system is pressurized by engine heat. Thermal expansion of the water. The pump just makes flow and mostly bypasses when the thermostat is closed.

So in theory, leakage in the engine shouldnt put oil in the water unless theres a major failure in a cylinder head or block. Oil pressure is higher than water pressure so it is possible theres a leak in a head gasket forcing oil from an oil passage to the valves into the coolant.

+ drain the oil, check for water in the pan
+ compression test. Look for rust and water droplets on the spark plugs.
+ check for bubbles in the radiator from a leaking head gasket while the engine is running. A good shop can test the air in the radiator for exhaust gasses that prove a head gasket leak. They use an exhaust gas analyzer. A bad leak might blow up a plastic bag held over the radiator cap opening.

 

well he finally did the pressure test and come up with some low compression
there is no traces of water in oil but its also fresh oil as well i just got it from a half *** dealership and thats where i got screwed from the start.
im pretty sure its a bad head gasket but that leads me to my next issue as i cant just forget about the thing as im already invested this far and its the truck ive been wanting so...... is it better to swap gaskets at a trusted shop or should i look into swapping the motor myself?

 

IF (and only if..) the gasket ONLY is bad, its not rocket science to change one. The trick is getting the surfaces clean.

IF (and only if) there is damage to the head, block or cylinder sleeve then the head or deck have to be machined. At that point its "put a hole thru it and get a reman engine"

Next step, get a head gasket for that engine and look for the oil passage holes - are they near the water jackets? Thats a cheap easy thing to do to get an idea of whether its a blown gasket.
If it happens to be a 4.3 Vortec and you dont have a gasket, I have some of them and could look at it and try to make a guess or send a picture to you.

As far as the cylinder pressure goes, it can be

1. leaky valve
2 bad rings
3 bad head gasket
4 some or all of the above

The standard test, to isolate the piston rings, is to dump a couple tablespoons of motor oil down the spark plug hole, rotate the engine around to soak the compression rings in oil, then recheck the cylinder pressure.
The oil wont seal up a leaky valve or head gasket.

Valves can be checked by pouring gasoline down the stems and see if it leaks into the cylinder. A leaky valve probably cant put "oil in the water" but could be a source of low cylinder pressure not related to the "oil in water" problem (a different diagnosis)

Its a tough diagnosis from outside...

 

I had the oil in the water issue that I resolved by changing the lower intake gasket.

The low pressure on cylinder 2 can be further diagnosed with a leak down test if you hear air going into the intake check the intake valve if the exhaust is noisy then it's that valve.

Define low pressure for us please