How hot does a car have to get till it causes major engine damage my car recently over heated big time the colant was boiling out of the tank and my car let out a blanket of steam

 

This is a difficult question to answer but I'll take a crack at it. It largely depends on the engine and how it is constructed: iron or aluminum, inline or V, type of headgasket on it. There are some rules of thumb. Running a engine hot without significant loss of coolant (meaning the recovery tank only gets full to the top) will not result in engine damage. So there is a difference between "run hot" and "overheated". It is only when the internal engine parts are uncovered (ie: in contact with steam instead if liquid) that damage can occur. If you look at the V8 engine as it begins to empty out, the displaced coolant that fills the recovery tank is the coolant at the top of the engine. When the recovery tank is full the parts of the cylinder head that face the combustion chamber are still covered with liquid. The parts that are under the valve springs will be the first to be "uncovered".
When the coolant continues to be pushed out of the engine and the tank overflows it becomes a measure of: how much coolant was lost and if the engine was allowed to cool before cold coolant was poured back into the engine. It is almost always the case that the cold coolant being poured into the overheated engine is what cracks cylinder heads. You can hear it. It sounds like someone hit the block with a small hammer. Clank!
(in the real world, overheated engines are never allowed to cool before cold water is poured in them) It is instinctive that a person wants to get the engine "cooled down" quickly because they have places to go.
If the engine is run with excessive coolant loss hot enough to damage the heads and allowed to cool, the heads will be cracked in multiple places. I have magnifluxed an iron head from a severe overheat and when we turned the magnet on, it looked like a spider web was draped over it.
About headgaskets: The most common damage in a "minor" overheat is warped cylinder head and damaged head gaskets.
If an engine has overheated and damaged the headgaskets (heads not cracked) the heads will need to be resurfaced. Too often the heads are not checked and just the gaskets replaced and the engine consumes coolant causing it to overheat again even worse because the coolant loss cannot be seen.
Checking an engine after an overheat: Find out why it overheated and correct it. With the engine cold, fill the cooling system completely to the top. Pressurize & maintain the system to 2 psi above the cap pressure for an hour. (now is a good time for prayers) Then de-pressure the system and check the level. If there is any drop in the level then the heads must be pulled.
Other topics if you think this post isn't long enough:
"head cracked, did I crack the block? what about the pistons?"

 

how long was it overheating for?

 

It depends on how hot and for how long. Remember that the temp guage is water temp, the engine is much hotter than the water.

The first thing you want to do with an engine that overheats is a compression check. This will tell you the condition of engine; Rings, valves, head gaskets, warped or cracked heads.

 

Hmm...? What were you doing that caused it to get so hot? Seems kinda odd for a car to over heat in the winter time. Does it have enough and coolant and water in it? give us more information on what happend and how it was running before this happend.

 

i left it running and forgot about it when i remembered and came back outside it had been. bout 20 minutes and the temp gauge was sky high.found out that the fans had stopped working somehow when it was running

 

.

 

It happens all the time when coolant freezes.

 

That was smart