What did I break (frozen radiator)
 

So my brother borrows my civic, which had been sitting for a while. Evidently it was short on coolant, as it started to overheat on him. He fills it up with water and of course we get a 15 degree low over the weekend. Where should I be looking for problems?

Re: What did I break (frozen radiator)
 

well for starters, warm the car up for about 15-20 minutes. than take the rad out since it will still be frozen. pop the drain plug off the block and let it drain. then reinstall the plug. after that you want to take the rad inside overnight or just start running hot water through it in the tub or a basement sink. when you go to put the rad back in your going to want to fill the rad then pour some of the coolant/water mix through the heads water port to fill the block up again with coolant. more than likely if you dont do that your block will get fudged because the thermostat hasnt opened yet.

Re: What did I break (frozen radiator)
 

We'll get up above freezing during the day, so I can run antifreeze through it then. I'm just curious where I should look for leaks since it was likely a block of ice overnight.

Re: What did I break (frozen radiator)
 

leaks will be the least of your worries. i just did this though as i had left the water from summer in my motor/rad and didn't change it because i didn't plan on driving the car at all this winter. mine was frozen just like yours and i did what i told you to do and i haven't had any issues yet. once you get it all changed out and let the car get up to operating temp you should be good. you may need to add a little more rad fluid though after a decent drive. maker sure your heater core is open all the way and on full blast to get the ice in it thawed lol.

Re: What did I break (frozen radiator)
 

I did the same years ago on my civic.

It warped the head so bad you could see light under it when the head was sitting on a precision flat table.

it took most of the day to warm it to get all the ice out. After we looked at it we pretty much said motor swap.

Re: What did I break (frozen radiator)
 

do you have a heated garage you can park it in for a few hours? just let it warm up...?

Re: What did I break (frozen radiator)
 

do you know for sure its frozen inside?

if there was still old coolant in there, it would have mixed with the new water and still may have been fine.

but yeah, not good to leave water in the cold weather.

Re: What did I break (frozen radiator)
 

ha! reading this just reminded me that i have water in mine too... i better get out there adn change that. even though this winter weather feels like fall weather over here in tn.

Re: What did I break (frozen radiator)
 

Get the car into a heated garage and let it sit for a few hours/over night and once the coolant/water is no longer frozen, drain and fill with a 50/50 mix. Run the car and check for any obvious leaks or issues.

Re: What did I break (frozen radiator)
 

drained mine at 36*F outside! thanks guys I have the typical intake tab leak on the top of my radiator, I have been putting water in it all summer, just read this and changed it before it froze, if the radiator is frozen since the tanks are plastic look at all 90* bends and brackets, those are the weak points in the plastic, also check the tubes, and lastly the waterneck, if you want to see if its frozen take the cap off and start the car, check to see if you have any circulation in the top of the rad... oh, and check for leaks at the alum./plastic joints between the tanks and the core...

Re: What did I break (frozen radiator)
 

If the radiator froze, I'll imagine the engine froze too. Crack the block. Needs new engine block.

Re: What did I break (frozen radiator)
 

That's not necessarily true, I'm pretty sure the frost plugs are intended to pop out before the block cracks.

Re: What did I break (frozen radiator)
 

bump

Re: What did I break (frozen radiator)
 

your block can crack even if you don't start the car, it's the expanding of the frozen water when it thaws that will crack it.
Remove all the coolant hoses, radiator, caps, drain plugs etc., so the coolant has somewhere to expand into. That's really your only option