Leaks coolant were could it come from

1. If you need to jump start the car the battery is failing and you need to replace it. Other wise you may have an excessive power drain while the car is sitting which is running down the battery sufficiently so it will not run the starter motor.

2. If you have a low coolant warning light then you need to check the coolant level in the radiator when the engine has cooled and top it up using only the correct spec coolant for the car as specified by GM. Coolant level in the radiator needs to be checked very regularly in any event as does engine oil and power steering fluid level. If the coolant is low your engine will overheat and will likely cause very expensive engine damage many times what it will cost to fix the cause of the low coolant. You will have an external leak(such as a leaking radiator or leaking hose or failed radiator cap etc etc ) or an internal coolant leak that is causing the loss of coolant. Whatever the cause, and you need to have it investigated and repaired straight away if the cooling system continues to lose coolant.

Hi Ayaz
if there no leak detected that means the radiator cap is not holding the pressure, that cause the coolant to travel to the expansion tank and flood out, then when engine cool down, it will suck the coolant back to the radiator and leave the refill tank empty.
Replace the Radiator Cap

Good luck

What is your question? You should not operate a vehicle that overheats. You should not put just plain water in a cooling system for a car. You can see the leak? You should get it fixed before any more damage happens to the engine. Failure to keep the engine cool can cause a host of problems and none of them are cheap to fix.

The adding adding coolant means you have a leak somewhere, and low coolant level will cause this. How often do you check the fluid levels? Check for leaking hoses, weak radiator or expansion tank cap, leak at the water pump, and leaks around the radiator.

It is a leak in the fuel evap system. This can be caused by a loose gas cap. If the cap is not loose then there is a leak in the system. That model Impala is known for the return solenoid going bad. It is located by the gas filler. They run about $40. I have included a link from a forum that may help you if you are mechanically inclined.
http://www.impalaforums.com/chevy-impala-8th-gen-discussion/121840-2006-impala-3lt-p0455-large-evap-leak.html

You've already eliminated #3 and #6, so keep checking...

Priority Action Part Type Cause
1 Inspect Radiator Cooling System Clogged.
2 Inspect Radiator Radiator Fins Obstructed.
3 Inspect Radiator Cap Worn or Damaged Radiator Cap.
4 Inspect Radiator Fan Motor Faulty Fan Motor.
5 Inspect Belt Incorrectly Routed, Adjusted (Tensioned), Missing or Worn Drive Belt(s).
6 Inspect Thermostat Faulty Thermostat.
7 Inspect Water Pump Worn, Cracked or Leaking Water Pump.
8 Inspect Radiator Fan Relay Intermittent Failure

Thanks for choosing FixYa and welcome to the site. I see that you have changed a lot. Make sure you have no leaks. Make sure it is not leaking inside the engine. Inspect the vehicle engine while it is started to check for leaks. Since you have changed all the other parts, what about your coolant sensor? Also, if your check engine light is on, you should take it to Autozone to be scanned for codes. They do it for free.

try to replace a new rad. cap-if still leaking & original radiator-then the tanks are wearing down,try putting some stop leak in it momentary-radiator may need to be replaced-not that big of job,you can do yourself-shops will charge $$$$$ hope that helps-good luck!

There is no sensor for a loose gas cap. What is happening is that the evaporative emission system is sensing a "Large Leak". Usually code p0455. The computer sees this as the most probable cause is a loose gas cap depending on several factors it looks at. You would need to clear the code(s) and see if that was the problem. If the light comes back on, then you have a problem in the system that will not let it seal. Possible solenoid problem, leaking hose / line, etc.

the best thing to get is the Haynes manual for your car at advanced auto or autozone or somewhere like that and the book will tell you how to take everything apart and put it back. i think the manual is about $16.00