Okay... not sure where to start, but basically when the car idles, the Temp shoots up towards redline and heater starts blowing ice cold... put it neutral and rev it up to 1500-3000 and the temp drops down to 180 and the heater blows hot again... wtf is wrong? thermostat stuck closed? Been having overheating problems ever since I replaced the water pump and i've probably bled the system 3times now... bout ready to just replace the thermostat and radiator and flush the system... Please help... TIA

 

go the cheapest way first. Sounds like something is clogging the system. Try flushing out the heater core and the rest of the system while your at it. If that doesn't work go try the thermostat and so on up the money chain. A radiator is some big bucks.

 

I'm definately not the brightest guy when it comes to cars... is the Heatercore part of the cooling system?

 

http://shbox.com/1/heater_hoses.jpg Check this link out. Courtesy of shoebox. His site kicks Ars.

 

the heater core is located in your dash and yes its part of the cooling system.. at least coolant runs thru it. when you turn your heater on a fan blows air thru the heater core just like your cooling fans do with the radiator.. heater core is basically a very small radiator in your dash. so since you dont feel any hot air with the heater on then my guess is the coolant either stopped moving thru the system(clogged) or you have air in it. since the motor also gets hot, my guess is a clog b/c the coolant must be also be setting still in the heats at the same time.

another way to check would be to hook up a scanner to your car and monitor the engines coolant temp that way. since the PCM uses a sensor located on the waterpump and your dash guage is located on the head.. you could see if the readings are close. if they are not then that would also indicate a clogged system or air bubbles.

 

May be a stupid question, but if I had the EGR system removed, could that be throwing the computer off and making it think that it's overheating?

 

coolant sensor went bad... gotta replace that too

 

no... EGR has absolutely nothing to do with it.

 

im having the same problem with my new motor, the motor at idle gets into the red, but the heater blows cold, and the metal lines going to and from the heater are cold

 

So why does revving the engine up help cool it off?