So I just replaced my Radiator with a Loyyo brand that I got from a local place here in los angeles, Thermalstat with new gasket & both top & bottom hoses for rad I got at the dealer cause it's a couple blocks from my work & didn't have time to wait for shipping cause my old had blown.

I spent yesterday flushing car because I had the toyota red coolant & wanted to make sure it was all out because I'm switching back to nissan green. I did my last flush this morning & water was clear, I also blew into the top block intake so that all the water would come out & pour new coolant into it so that it would have some when I start the car.

I started car and waited till it warmed up and checked for any leakage & did not see any, I then drove car keeping an eye on gauge temp & it stayed at 3rd line (normal) & after 6 blocks into it I notice temp started rising rapidly so I pulled over & let cooled, I also checked for leakage & did not see any.
After I let car cooled for half hour I drove back to my house and saw temp stayed at normal & when I got home I got out to check for leakage and saw none & I notice that the fan was on so everything looked fine until I went to shut off car I saw temp climbing back up.
This has me puzzle because I make sure I put everything back that way it was & I could feel both hoses hot so I know coolant is circulating, so what can it be? bad thermalstat? any ideas?

 

You've probably still got air in the system.

 

Stupid of me I forgot to check the rad for fluid levels, will check tomorrow morning, I just started freekin out. Thanks for quick response.

 

bleed more

 

Your car is showing the exact same symptons I had with mine. I also replaced radiator and thermostat along with flushing my cooling system a couple of times (the old coolant was red, not because of the color of the coolant but because of corrosion sediment). In addition to that, I bled the system twice, revving the car for as long as 30 minutes as it was parked on an incline and with the front jacked up as high as I could, so that the radiator opening is above the heater core level. In the end I ended up replacing the water pump which was the source of the problem to begin with; the fins were completely gone.
I sure hope you issue is just the need for purging the air out of the system.

 

Hey Scottwax you were right, added about 1/4 of gallon this morning and that's all it was. I still heard the bubbly noises as I drove it for the first two miles on my way to work and notice that the reservoir had gone down a bit when I got to work, also the temp gauge remained steady at regular line/temp. Will check for leaks again after work & refill reservoir before I take off.

One last question, since I put the nissan coolant and it's already 50/50 and I know block had some water in there (I estimate about a quart) cause I didn't unbolt the block screws is it wise to drain radiator once or twice and refill with coolant so it can become close to 50/50?

 

You can check the coolant's specific gravity to see what the freezing and boiling points are, and make that decision then. I prefer non-pre-mixed coolants for this reason. Ethylene glycol is the same the world over, and as long as the additives get along with aluminum parts (and already-present additives) you're good to go.

In the "I am new but have questions" thread a few pages back I posted this on clearing out the air in the cooling system/filling it with minimal hassle. Works on most vehicles this way, except for Dodge Darts, K-cars with US engines, and, well, anything else with an asinine cooling system with high spots in there that block things.