[juldazy]

Hi, I recently had problems with the cooling system on my m43b19. I changed one hose and drained the coolant. I did my best to bleed the system. Once the car started it would get to optimal temperature when idling, but when I was riding the temperature was getting lower, sometimes averaging around the first line. What could be the issue?

 

[yjsaabman]

Running exceptionally low temperature is usually an indicator of a thermostat that is stuck open.

 

[Bali]

Running exceptionally low temperature is usually an indicator of a thermostat that is stuck open.

^This. A soft failing thermostat.

Forget the temperature gauge as it is buffered and lies.
Use an OBD app or the cluster special test to view the actual coolant temperature.

 

[LL i am]

Once the car started it would get to optimal temperature when idling,

Running exceptionally low temperature is usually an indicator of a thermostat that is stuck open.

^This. A soft failing thermostat.

yisaabman & Bali, so how u get optimal temp when idling with stuck open thermostat? i had failed open thermostat, and it did not go past the first tick mark on the gauge, idling or 100 mile trip.

 

[shadetreemech]

My experience with this was if it was stop and go driving at slow speeds the engine would warm up - slowly. The 30 minute drive to work could get chilly though.

 

[Sapote]

Once the car started it would get to optimal temperature when idling,

Use the hidden menu display to show the actual coolant temp, as we don't know your optimal temp.

 

[yjsaabman]

yisaabman & Bali, so how u get optimal temp when idling with stuck open thermostat? i had failed open thermostat, and it did not go past the first tick mark on the gauge, idling or 100 mile trip.

No or minimal airflow through the radiator when stopped doesn't provide the same level of cooling as when moving with airflow through the radiator. Soft failing meaning it's not fully working, but not fully stuck open. Slow warmup is another indicator. And with the buffering, as Bali mentioned, the gauge will read normal even when the actual temperature is low.

 

[markusmarkus]

OP, google “BMW E46 hidden obc functions” to learn how to access the hidden menus and tests.

 

[TobyB]

... and then this board to find 'temperature gauge buffer removal' because it's really easy to do with BMWScanner 1.4,

and then your temp gauge will work like it should.

t

 

[juldazy]

Hey everyone, thanks for the answers. I can't go to hidden menu bcs my cluster button is broken. I saw someone mention software and that got me into one question. I had one tube from behind the engine on buckle that was suppose to be on the "click connector"(the hose i changed). Is it possible that the ecu is not yet fully synced with like the pressure or something? I can also look at temps in inpa so I will update soon

 

[Sapote]

I had one tube from behind the engine on buckle that was suppose to be on the "click connector"(the hose i changed). Is it possible that the ecu is not yet fully synced with like the pressure or something? I can also look at temps in inpa so I will update soon

I don't under stand the "tube" -- tubes are used on MacIntosh MC275.
Post pic of the "tube"

 

[juldazy]

I don't under stand the "tube" -- tubes are used on MacIntosh MC275.
Post pic of the "tube"

Sorry, English isn't my mature language. I meant hose that leads from changer(water valve) to the back of the engine(cylindrical head). The number of the hose i replaced is 3.