I have a 2000 2.7 that is over heating

 

what do you expect for an answer with this poor information ???

 

i have a 2000 audi quattaro a6 2.7

I'm having problems with it overheating. Could this problem be the thermostat? When we start the motorup and ran the heater on hot, it blows hot air out the heater for a short time. Then turns cold could this be a thermostat stuck open?
We bled the air out of the coolant system.

 

any fault codes?
could be numerous things. thermostat, water pump, cooling fan, temp sensor or a clogged radiator. is the coolant hot or cold in the coolant reservoir? upper and lower hoses on the radiator, hot or cold? is the fan kicking in?

 

we changed all the coolant hoses and o-ring in the whole coolant system last year also replaced the water pump last year. the fan kicks in after running a few minutes.

 

the water in the coolant resevoir seems to be getting hot real fast. what would cause this? the car has 136,000 miles.

 

If the thermostat is stuck closed, then the heater will blow really hot air. If the water pump is not circulating, then you will not get any hot water into the heater core, hence no heat. the reservoir is the highest point, convection will transfer the heat to it.

Does the radiator get hot too?

Unlikely, but possible... something clogging up the rad and heater core (radiator stop leak)?

 

It could be your water pump leaking or some other leak. When you lose pressure the car gets cold inside. Check if the you have high pressure in the system all the time.