Help with cooling system

My wifes 05 equinox started doing some weird stuff with the heat lately, when you first start the car and let it idle it wont blow hot air, it can idle for 20min and no heat, as soon as you start driving the temp needle (not really a guage) will go up a bit then the heat will work, then it goes back down again and the heat goes away, if you have heat then stop and let the car idle the heat goes away, rev it up an dit comes back. at first i was thinking thermostat so i figured its cheap and easy to replace so i did, no difference, still does the same, now im thinking water pump, its a extternal belt driven one, im thinking it really has to be turning good to pump the coolant around. Any suggestions besides move somewhere warm?? if it matters it has 105k on it

Did you ever have the cooling system serviced? Grab the hoses going to the heater core are they hot?


Eric

no the system has never been flushed (that i know of), i think thats what ill do next before i replace the water pump.

BeerMonley wrote:now im thinking water pump, its a extternal belt driven one, im thinking it really has to be turning good to pump the coolant around. Any suggestions besides move somewhere warm??

If the water pump was bad it would overheat. Either it's low on water or the vacuum valve on the heater hose is failing. Look under the hood for the two heater hoses. One of them will have a valve on it. There is a small lever on that. Have someone turn the heat on and watch the valve lever. You know which way it opens now, hold it open and see if the hose going from it to the firewall gets hot. If you must, tie/tape/whatever it open. A lot of miles and the vacuum hoses dry up, crack and then leak or the valve starts to fail. Tie it open and you have heat.

coaledsweat wrote:

BeerMonley wrote:now im thinking water pump, its a extternal belt driven one, im thinking it really has to be turning good to pump the coolant around. Any suggestions besides move somewhere warm??

If the water pump was bad it would overheat.

Not always, I have seen more than one pump that the impellers were almost gone and temp was perfect, but they could not develop enough flow to move the water to the core. I am not saying this is the problem, but just cause there is no overheat does not mean there is no water pump problem.


Don't waste time to flush the whole system yet, pull the hoses off the core and spray a garden hose in the one and see how much comes out the other end. If that seems ok have someone start the car with out the hoses on the core and see how much coolant pushes out the hoses when car is running. Remember always catch any spilled coolant . It just sounds like a flow issue cause you said if sped up you get heat.


Eric

ive been told to try the taking the hoses off the heater core on another forum to. i was also told to run the hose through the core opposite of the way the coolant goes thru it to see if any junk comes out.