2004 325CI - No fluid flow (everything replaced, but engine)

[curlyp]

Greetings all!


I am reaching out to the forum for some advice about my parents car.


My parents own a 2004 325CI with 70,000 miles. The other day my father went to use the heater to remove the steam from the front window and there was no heat (air condition works). My father took the car to the shop that specializes in BMWs and the tech said no fluid is flowing through. He had the thermostat housing, radiator expansion tank, expansion tank retainer, heater control value, and radiator tank replaced. That did not fix the issue. He took it to his local BMW shop and they replaced the water pump. The technician said the radiator only reaches 130 degrees when it should get to 180 degrees. The gage in the car stays in the middle and the car has never over heated. At this point, everything has been replaced expect the engine.


The car is in the shop and the technician is resuming diagnostic today. Before the weekend, the technician relayed that this one has him stumped. Does anyone have any idea what could be wrong and why fluid is not flowing at all?

Thanks!

[randy72877]

It sounds like the people at the shop have no idea how a cooling system is supposed to work. The radiator should not be at engine temperature. If the radiator gets that hot, it would indicate a problem. Upper hose should be hot and lower hose should not. The thermostat regulates the engine temperature by opening and closing as needed allowing hot coolant to flow into the radiator. This seems to be working. Coolant does not flow continuously through the radiator. If there was no flow in the cooling system, the car would not have heat and overheat quickly. Assuming the heat is working good, it seems like everything is working as it should. This is basic automotive principles that all cars operate on, not bmw or e46 specific. These people really don't know what they are doing.

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[curlyp]

It sounds like the people at the shop have no idea how a cooling system is supposed to work. The radiator should not be at engine temperature. If the radiator gets that hot, it would indicate a problem. Upper hose should be hot and lower hose should not. The thermostat regulates the engine temperature by opening and closing as needed allowing hot coolant to flow into the radiator. This seems to be working. Coolant does not flow continuously through the radiator. If there was no flow in the cooling system, the car would not have heat and overheat quickly. Assuming the heat is working good, it seems like everything is working as it should. This is basic automotive principles that all cars operate on, not bmw or e46 specific. These people really don't know what they are doing.

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Thanks for the information randy. Unfortunately, the heater does not work at all, only the air-condition. My father told me when they remove the hose there is no fluid coming out. However, when they hook a machine up to the water pump (I think) and apply pressure, they are able to make the fluid flow through everything correctly.

[randy72877]

They probably have not bled the air out of the cooling system properly. If stop leak was used in the cooling system, the heater core could be plugged. These cars have been on the road for 20 years now. Any shop that claims to specialize in bmw should be able to fix or at least diagnose this easily.

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[Slitherbeast]

Thanks for the information randy. Unfortunately, the heater does not work at all, only the air-condition. My father told me when they remove the hose there is no fluid coming out. However, when they hook a machine up to the water pump (I think) and apply pressure, they are able to make the fluid flow through everything correctly.

The water pump creates the flow.... They may have changed the water pump....... If they inspected the water pump they may have notice that the impellor looses pieces that get lodged either in the Heater Valve or the inlet to the heater core. You should remove and inspect the heater valve for debris clogging it and do a REVERSE flush of the heater core. I like to get a 3/8" hose and syphon the coolant from the expansion tank. ( takes abit of time but is easy) Then disconnect the top hose from the heater valve and add a small length of hose to route the flush to a pail/containment. Disconnect the heater core return hose from the bottom of the expansion tank and put a funnel into the hose. fill the funnel with water and see if it drains. If it doesn't it is plugged. Use some compressed air ( it will be messy) or hookup a garden hose to this hose and carefully push out the pluggage. Re assemble and replace the coolant. after it is properly bled there should be heat... Hope this helps.....