2000 maxima se heat problems

[bk00maxse]

i have a 2000 maxima se and i been having problems with my heat.the heat works only when i am driving and its not that hot its luke warm when i am at top speeed it still feels like the heat is on and the reserve tank gets so full sometimes the antifreeze starts to leak i dont know if i have to get the system bled out or if i have to change the thermostat this is getting really annoying cause its freezin in ny and i need heat

[Beancooker]

Wow, I'm not sure. Usually when the reserve tank gets overfilled, it's because you're overheating. When you're overheating, the heater blows REALLY hot air. Unless the heater core is out, in which case, you'ld most likely have a puddle under the car. If the thermostat sticks shut, you over heat, if it sticks open, you never get hot enough...

When you have luke warm heat, and the overflow tank is bubbling over, what does your temp gauge read?

[bk00maxse]

my temp gauge is normal all the time the car is not overheating i just dont get enuff heat i dont know if the thermostat is not opening or if the radiator is clogged the

[Beancooker]

Is your overflow tank overfilled?How long ago was the last time you flushed the coolant system?

I'm thinking thermostat, but the overflow tank has me stumped. Hopefully someone else has some advice also.

*EDIT--This is only a hypothesis....One other thought is that it could be the water pump. If the pump is not circulating the water, then it will only circulate from the pressure that is generated from the water boiling in the block. If this were the case thewater may never get to the heater core properly, and could cause the thermostat to open, and boil _backwards_ into the radiator, causing the overflow tank to overfill.

What is the temp of the water in the overflow tank, when it bubbles over?Cool?Warm?Hot?Boiling?

[WDRacing]

Mixer valve that allows water to enter the heater core could be faulty. Maybe only opening part way. Water doesn't always go through the core, the valve has to open.

If the thermostat was bad, you'd have one of those indications above. The car will get up to operating temp, but it will take forever if its stuck open. However, most thermostats stick closed. In which case you'd over heat.

I dunno why the overflow tank would "overfill". Usually this does not happen until you're about to overheat. Are you sure you're operating in the correct range?

WD

[bk00maxse]

when i rev the car it sounds like water in my dash and its kinda strange in order for me to get heat when i get to a red light i have to put the car in park then pump the gas to about 5000 rpm then back into drive this is really crazy and with all that i only get heat for 2 to 3 minutes after that it blows luke warm

[WDRacing]

You need to drain and purge the system. Make sure its bled well upon filling.

[bk00maxse]

is there a special machine used to purge or drain the system is that the same as a flush?how much should it cost to get the system purged this dude told me 75 is that a good price to get it done?

[WDRacing]

Sorry, I'm ex-military, so I use the old military lingo. A flush is in order and good system bleed.

[bk00maxse]

got the system bleeded and still i only get heat when i am driving 40 to 50 miles per hour its the thermostat the dealer told me they changed it but they never did i am going there tommorow to start some serious problems

[WDRacing]

Well let us know what happens, gotta love dealerships

[bk00maxse]

got the heat bleeded and had the thermostat changed still no difference and i also had the intake taken apart and the heater core was blown i dont know what the problem is and i also notice the radiator reserve tank bubbles what could be this problem i am ready to sell this car if i cant find a solution to this heating problem