Severe cooling issues

[railgun]

Ok, let me give you the quick run down...or at least as quick as I can make it.

So I had pulled the motor over the winter to fix a pan leak. No other changes to the setup other than wrapping exhaust components, etc and re-added the ISC.

Put everything back in, refilled the coolant with some distilled water, burped it a few times from the lower rad. hose and fired it up. Naturally more needed to be added, which I did as needed. While I was working on resetting the idle I looked at the temp gauge and WTF!? it's at almost 260! No, no coolant buzzer. Yes it worked as it went off a couple times while filling.

So the top rad. hose was hot, the lower cold. I mean as if no coolant was flowing through the radiator at all kind of cold.

I'm going to be pulling the rad this weekend and try to get some coolant to flow through the motor. I'm 99.999% sure it's not the pump as revving adjusted the water level as I would expect it would as the pump spins up/down, etc.

So, any initial thoughs on what it could be? I blew out the radiator before hand....and now I'm thinking something I don't want to think about.......

I hope to hell that some f'n mouse didn't crawl up there over the winter.