Electric fan is not working.

 

I have a mechanical fan and it seems to run fine. Do you mean the secondary (inf front of the car, air conditioning) fan? if this so, should I change the radiator outlet temperature sensor (attached to the lower radiator hose).

 

If the car is overheating or getting too warm, the fan should be LOCKED UP.
Is it?
If not two things are happening.
A: Fan clutch is no good.
B: System not properly bled and radiator is cool.

Very much likely "A".

 

How do I check the clutch? Really appreciate your help...

 

Why did you do all that work? Was it simply preventative maintenance? Or was there a specific reason you replaced all this?

 

The heater pipe busted, and it overheated the car. Then the radiator cracked by the drain screw. The rest of the items were replaced as preventative since I have everything open.

 

I missed this post earlier. OP may have a blown head gasket. Let’s see what his shop says.

 

Roll up a newspaper, car fully hot (not overheating) the fan should try to shred the newspaper. If you can easily stop it and/or spin it backwards it's toast.

Prerequisite is that the thermostat has opened and hot coolant is now in the radiator. The hot air activates the fan clutch.

 

On the E46, the electric fan is the primary cooling fan and absolutely must be working properly. Overheating at idle is typically because the electric fan has failed.

Your automatic transmission E46 has a "pusher" electric fan in front of the radiator. All but the earliest manual transmission E46s have a "puller" electric fan behind the radiator and no mechanical fan.

Check that your electric fan is running when the engine temperature rises above normal.

Read BMW-North's Electric Fan Guide for all the details.
https://drive.google.com/file/d/1BMHsmEwoEuSPkOuTpuLRnETy1XTielvZ/view?usp=drivesdk

 

Thanks for the help, I will check the fan clutch using the news paper.

As for the front electric fan, it does not work when the engine gets hot. It does run when I turn on the A/C, but stops soon as I turned it off.

 

Thanks for the help, I will check the fan clutch using the news paper.

As for the front electric fan, it does not work when the engine gets hot. It does run when I turn on the A/C, but stops soon as I turned it off.

There's your answer, whether you have a functioning fan clutch or not.

 

Thanks for your help....

 

I did the newspaper test, and it failed. I have ordered a new clutch.... Thanks again.

 

Don't buy the Meyle fan clutch...makes too much noise because it grabs too early and too often...

Sachs or Behr for fan clutches....

 

Ok, I am at a loss.... Changed the fan clutch, and problem still exist. The only thing left to do is to change the WP and Thermostat.... Should I go ahead and do that, or there is something else I am missing....

Please help, I am a bit frustrated!

 

So it overheats at idle, but goes back to normal once moving? Did you review bleeding process?

 

What happens if you turn on AC at idle?

 

It goes down when I turn the heat on at full blast. When I turn the A/C on still overheat. I followed the bleeding procedures in this forum as well....

 

Did you drain the entire system when you added the new parts? What happens if you turn on the ac

 

I only drained the radiator portion, did not drain the engine block...

 

The same 'clutch' is used whether the A/C triggers the fan or the coolant temperature does -- if the A/C triggered the fan before, and the fan ran, the clutch was working. It would seem to me you've narrowed it down to a relay failure, or a temperature sensor one. If it's the same relay that starts the fan with the A/C (I'm not sure) than the problem is clearly with the temperature sensor. I believe the sensor to trigger the fan is not the same one sending a signal to the gauge, but I'm not sure,

My answers a touch vague as my BMW has never had any overheating issues, but the logic is similar in my LT1 Trans Am. Look at the trigger, not the fan/clutch, as it works when the A/C is on.

 

If you have a new fan clutch and the fan shroud is installed it should 100% keep the car cool.
You have a few possibilities:

1) The system isn't properly bled (you said you did, so this is a reference for others.) and not all of the coolant is in the radiator: Top half of the radiator is air/steam and not coolant.
2) The thermostat isn't functioning correctly and waits too long to open and send hot coolant to the radiator for the new fan clutch to do it's thing.
3) The water pump is not flowing correctly.
4) The radiator could be clogged (internally as well as externally) acting as a VERY poor heat exchanger.

I'd start with checking the coolant level cold to verify fill. Then start the car with the cap off (for just a moment) and have someone hold the throttle @ 1,500 to verify flow.
Then I'd see if you can blow out the radiator from inside to outside. You'd be shocked how much debris/bugs come out of the fins.

Q: With the car just starting to overheat, is the air being drawn in by the new fan/fan clutch VERY hot or lukewarm?

 

First of all, thank you all for your help and patience...

The radiator is brand new, and don't believe it is clogged.
To give more details I have a scanner that display live data. The engine temp. sensor was reading around 240F when the gauge start to over heat. I have another reading for coolant inlet temp. and it shows around 170F. I did change the temp. sensor that is located on lower hose from radiator (passenger side). The air conditioning fan (aux. fan) work only when the A/C is turn on but stop soon as the A/C is turned off. This happens even when the car is overheating.

Additionally, I did the news paper test on the new clutch and it failed when the car is overheating.

To answer the question about the fan air, it seems that air is lukewarm when the car is overheating....

 

The radiator is brand new, and don't believe it is clogged.
To give more details I have a scanner that display live data. The engine temp. sensor was reading around 240F when the gauge start to over heat. I have another reading for coolant inlet temp. and it shows around 170F. I did change the temp. sensor that is located on lower hose from radiator (passenger side). The air conditioning fan (aux. fan) work only when the A/C is turn on but stop soon as the A/C is turned off. This happens even when the car is overheating.

Additionally, I did the news paper test on the new clutch and it failed when the car is overheating.

To answer the question about the fan air, it seems that air is lukewarm when the car is overheating....

It just seems odd that the coolant outlet temp on lower rad hose is 170F (sounds too low) while the engine coolant temperature is 240F (too high) as measured at back of engine under cylinder #6 under the intake, while at the same time the heater is blowing lukewarm air.

Seems like either an air bubble or lack of coolant flow for some reason. Perhaps rebleed with the front of car elevated and confirm coolant flow as mentioned above in post #23.

 

MrMcar: its hard to keep track of which overheating thread is which. OP says he put in new rad. Sure sounds like lack of airflow at idle.
Maybe bleed again?
Wouldnt a bad thermostat or pump affect cooling at speed too?

 

Could you clarify thd bit about the new fan clutch failing?

 

I waited until the engine is up temp, and I took a bunch of news paper and tried to stop the fan from spinning by pressing gently against the blades. If the fan stops spinning, then the clutch is not engaged/locked to match the engine speed. So, when I did that, I was able to stop the fan from spinning

 

So from the above feedback, it seems that I have a water flow issue as it maybe stock in the engine. so which part control the water flow, WP or the Thermostat.... BTW, I am not getting any code, I scanned the car and no codes are present....

 

Try the test in post #23 above, that involves removing the cap and observing if there is coolant flow. On a cool engine, I believe. Water pump creates the flow, t-stat regulates how much goes to the radiator.

Yup, the lack of error codes does not mean everything is ok.

 

Whats odd is that teh fan clutch is not engaging. But I agree, try another bleeding.