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Heater problem

Discussion in 'E39 (1997-2003)' started by deancook, Dec 14, 2010.

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    I replaced my radiator, expansion tank, water pum and hoses. I have attempted to bleed the system by elevating fron end but the heat will not get above 72-74 degrees. There are no visual coolant leaks but have not had pressure tested. Any suggestions? 2002 E39 525i
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    Thermostat stuck.... ?
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    These things are a huge pain. There are 2 bleed screws IIRC. Make use of both of them. They are plastic, so don't overtighten them.

    I often remove the upper hose from the radiator and pour coolant down the hose to fill the motor. Works much better that way, though it is messier.
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    Thanks. I have continued to elevate front end so air comes to front and bleed the system. It improves each time. I just did this again today and it appears fixed. Thanks for your help. The thermostat was not stuck. If it proves not to be fixed I will try the direct pouring into upper hose.
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    Here's a few tips:

    Elevate the front of the car so the bleed screw in the upper radiator hose to the thermostat is the highest point in the system.

    Both bleed screws should be closed.

    Turn on the heater to it's hottest setting and the fan to the highest speed.

    I started by turning the ignition key to the ON position and using the recirculating pump at the bottom of the radiator to slowly move coolant into the system, via the expansion tank, until the radiator was filled.

    Once the radiator is filled, start the car. Top off the expansion tank as more coolant is pulled into the system. Once full, put the cap back on the tank.

    Intermittently, open the bleed screw on the expansion tank to bleed air, then close it. Open the bleed screw on the thermostat hose to bleed air, then close it. Do this maybe two or three more times until all you get is coolant and no air.

    I never had to bleed the system after this procedure.

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