Yeah i had the clamp on real tight on that video and somehow it started to spew out coolant, the cap was a little big so I had to replace it... and this time I made sure that clamp was tight.

To be honest with you I have no idea how the overflow is doing...
when I flushed it I disconnected the clamp that was connected to the radiator cap and started to drain all the water from there. Then I filled the overflow until it was full to the top. But when I checked it this morning the overflow didn't seem to be full?( I am not sure if the coolant in the overflow is supposed to stay at full or it's supposed to be a bit depleted so I did not add any more coolant to the overflow)
As far as I can tell there is one hose connected from the overflow tank to just under the radiator cap.

I also replaced that cap as well.

 

overflow should be about half full, radiator needs to be filled to the rim. the lowwer rim. coolant will drain into the overflow once you get over the first one.

 

as the coolant gets hot it expands and the extra coolant needs to go somewhere, it goes into the overflow, as it cools it contracts and it sucks the coolant back into the radiator if the overflow is not at the right level it can either suck air into the radiator if to low or overflow from the overflow if too full.

 

Hi!
z28 have a cooling passage under the passage on the neck of radiator that comes to reservior tank and over the passage of the transmission fluid.
You have nothing in the transmission passage so I think you have the manual transmission.
That hole i think is the level sensor for the cooling that is only on the 5700.
Change the rubber cap and the clip as Craby said and check if the pvc of radiator have cracks or damaged!

 

I'll give my advice one last time.

Get rid of that cap. You are only putting a band-aid on the problem. Get some hose that fits over the neck and tie into one of the heater hoses. You may have to adapt up or down to make it work but now you eliminated the potential for a big leak

Get a big funnel that fits nicely into the neck of the radiator. Run the car at idle with the cap off and the funnel in. The funnel will allow the coolant to expand and come out without making a mess. Do it till there are no bubbles in the coolant. If you can lift the front end slightly, it will help or do it on an incline with nose up. I again suggest the Lisle funnel as before because it has a neat feature that lets you plug the funnel so the extra coolant stays in the funnel when you lift it out, again, avoiding a mess.

I would do this before going any further.

 

I did change the rubber crab but I couldn't find any clips at autozone, its not leaking so far but it justs overfills :/

Thank you!

 

Ahhh Im sorry but I just wanted to leave the rubber cap for now because I bought 2 variety packs and I didn't want it to go to waste. You do have a point about the funnel, I do have one but its a bit a dirty I just need to clean it up and ill do it as you say And you are 100% right it just hasn't occurred to me at that moment... I should really use that funnel because every time I massage the coolant lines it's spilling like 2 cups of expensive coolant aghhh

About the lisle funnel I will consider it but I'm just trying to spend as little as possible. Ill get it if my funnel doesn't turn out to work..

 

Craby I love it when you teach me new things! Thank you!!

 

quick update today (4/3/17)



I haven't thought about using a funnel at the time.. I will be doing it next update

 

put the cap on and run it for a while. watch your temp and see how it goes. let it cool and check level. once it pressures up, temp goes up and coolant expands, with the cap on you dont want to open it. not a good idea to open the radiator when the car is hot or at operating temp. can get some nasty burns from hot coolant spraying out.