I have steam coming out of a small vavle next to my radiator cap, and it is overheating

Weak cap comes to mind

Look for a stuck closed thermostat first. Then make sure there is enough water in the radiator. Next look at the exhaust pipe. Is it black or a shade of tan? Is there steam coming from it when the engine is running? Compression gases getting into the water can mean a bad head gasket or worse a crack in the head or block.

Lets do this,stop driving it,until properly
diagnosed and repaired

It may be the radiator cap itself, but is most likely a crack that has formed around of near the radiator, causing steam to exit from this area. It seems like it is a small leak, otherwise the coolant loss would not be so gradual. Radiator replacement will most likely solve this problem after the radiator is inspected and a crack is found. I do not recommend the use of Stop leak to correct leaking radiators, in the long run, they do more harm than good.

Your engine is either overheating or your light is malfunctioning. The coolant may not necessarily "steam" from the radiator because the engine is overheating. The purpose of the light is to warn you of an overheating condition before it gets bad enough to cause your coolant to blow out the radiator cap. Severe engine damage can result from overheating. I would recommend having this problem diagnosed by a qualified technician that has the proper equipment required to to test and verify that your cooling system is functioning properly.

Overheating is not always caused by a bad water pump or bad engine firing timing.

The most common causes are:

• faulty radiator cap: steam/water will be escaping from the caps when engine is hot or oveflow tank overflows or empty!
  
• crack cylinder head gasket: check when engine is cold thru radiator cap hole for milky oil in water radiator or large bubbles in radiator water after starting engine. Also check if water steam comes out of exhaust.
  
• cylinder head itself: same symtoms as for gasket above.

Hope it helps you find your problems.

its the cap id figure but you mite want to keep the engine running in stand in front of the car with the hood open in watch fur leaks in or steam if it is coming out the top of the rad where the cap is it mite jus be the the cap theres a rubber peice on it that mite be worn

The fans are actuated by coolant temp in the radiator. It is possible to have overheated coolant in the radiator, causing the steam, and your engine not overheating...the temp sensor for your engine is reflecting the engine temp, not the temp of the coolant in the radiator. You problem could be a bad temp sensor at the radiator...not allowing the fans to come on. Good Luck! I hope you find this to be very helpful!

From your description of symtoms it sounds like you have a bad water pump. If the coolant is not circulating properly you will have a heating problem. Sometimes even a new thermostat can stick and cause the engine to overheat. I have seen them fail in as little as a week after they were installed.

I had the same problem, whole new radiator, new hoses, new thermostat, and still overheating. What the problem was for me...bad radiator cap...all that money and a $20 fix...try it?