Has no heat and why is the fan on all the time

60

Asked by Sep 08, 2011 at 12:44 PM about the 1999 BMW 3 Series 323i

Question type: Maintenance & Repair

4 dr. "VIN#WBAAM3332XCD56099  No heat.  Just replaced a radiator hose and now wondering if the thermostat is needed.  The fan stays on all the time.  Wondering what to do.

9 Answers

2,805

Also install the T stat of course, and "burp" the system of any air when replenishing the cooling system. Run the heater on full heat or on defrost. That way coolant makes it way the heater core (it's like a mini radiator). Some system "burp" differently. Usually you can back out the temperature sender switch (near the water pump) and that will release trapped air.

2 out of 2 people think this is helpful.
60

That did work but the fan is staying on so do not know what else to do but put a togo switch to the fan for the motor. Not sure what else to do. She has alot of miles on this vehicle. Over 200,00. Thank you for your help.

1 out of 1 people think this is helpful.
1,475

which hose did you change, the bottom one has a temp sensor in it. also there is a temp sensor on the block that could be defective. also get your fault codes read because the fan staying on can be linked to other issues with the engine.

1 out of 1 people think this is helpful.
60

Larry changed the upper radiator hose. He also checked the codes and no codes available. The thermostat assembly has been replaced with a new one. The fan still will not shut off. He did check all other hoses and the bottom hose is still cool while the upper one is warm. He is really baffled. Need help.!

5 out of 5 people think this is helpful.
2,805

"fan still wont shut off"??? Is the A/C on. Could be a faultly temp sender switch. If the lower hose is still cool then the T stat is not opening, probably due to the fan still running and keeping it cool. Try driving it and see if the T stat opens. Even though you replace the T stat housing the T stat could be defective or sometimes people put it in backwards or there is still some packaging plastic stuck on the assemble to make it stick closed. Other things to check for fan operation is AC pressure sender/switch, HI and LO speed relays.

2,805

If your burped the system and still no heat to heater core to blow heat then it could be the water pump. I know many BMWs have had plastic impellers on the water pumps and people usually upgrade to metal or alloy ones. This is also a common problem in VWs/Audis. Plastic and heat aren't a good mix the the plastic slowly deteriorates with no signs or typical water pump failure such as leaking shafts or squealing noise from bearings.

1 out of 1 people think this is helpful.
30

Got bmw 325 i no heat i replaced water pump,heater core,tstat,heater valve still no heat

3 out of 3 people think this is helpful.
10

Check your fuse first it soynds like the blower resistor

1 out of 1 people think this is helpful.
10

got bmw 325i replaced a/c condenser fan assembly, sill no cool air

1 out of 1 people think this is helpful.

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