This is from Dal's build thread over on M3F and a big thank you to him. Figured it will help someone here. Hopefully his build thread makes it over here, as it was very informative.
Electric Cooling Fan Retrofit
Last week, on my drive home from work I had some issues with my AC. Of all possible days this had to happen on the hottest
The cabin was hot as I entered the car, as expected. Turned on the air con and drove off. 15 minutes later I noticed the cabin was not being cooled enough. AC with the snowflake was activated but there was no cold air, just warm
The next day, during my commute into work I turned on the AC again with snowflake and cold air was coming how the vent, strange
As I reached traffic, my eye caught the coolant gauge. It was sitting slightly higher than normal. As the traffic got denser I noticed the gauge started 'running' towards the 2nd dot.
If I carried on with my commute no doubt it would of hit the red. Past experience from owners with coolant issues virtually always states to never let the car overheat as the repair costs spiral! ... And so I did a U-turn and headed back home in clear air. The coolant temp quickly went down due to the rushing air. I parked the car at home and didn't drive it again.
A quick look on the diags revealed this:
... The electric fan sits in-front of the radiator and condenser, it provides additional cooling and is controlled by the DME. Most of the time it activated when AC is used... so this explains why I was having AC issues a few days ago.
After some in-depth reading on the Internet, it seems the number one culprit is the FSU (Final Stage) control unit which sits inside the fan shroud. Having checked the fuse (which was ok) I decided to enquire with the dealer about getting a replacement fan unit...
Going to the dealer to find out the cost of a new fan unit...
No Thanks!!
I managed to solve it using new parts, much cheaper - here's how...
The E46 Pusher Fan
Pusher Fan Replacement
Extra Info
Bumper Removal DIY:
http://www.m3forum.net/m3forum/showthread.php?t=247135 - Thanks Obi
http://www.bmw-planet.com/lib/BMW_e4...Bumper_DIY.pdf - Thanks DaytonaViolet
E46 non-m3 pusher fan
The fan setup on the e46 non-m3 cars is a little different, some have puller fans so you need to be careful here. I'll include the part numbers:
P/N: 64546922554 or 64546988913
Going for new fan parts or old?
This is subjective. If you really want to make a huge saving you could buy used parts. Having gone through this I'm glad I used newer parts as its likely they'll last longer and this is not something I want to DIY anytime soon - spent all weekend on it!
In Conclusion
Although my issue is fixed I'm not stopping here. My car has 70k miles, and so I'm going to the following replaced soon:
Last week, on my drive home from work I had some issues with my AC. Of all possible days this had to happen on the hottest
The cabin was hot as I entered the car, as expected. Turned on the air con and drove off. 15 minutes later I noticed the cabin was not being cooled enough. AC with the snowflake was activated but there was no cold air, just warm
The next day, during my commute into work I turned on the AC again with snowflake and cold air was coming how the vent, strange
As I reached traffic, my eye caught the coolant gauge. It was sitting slightly higher than normal. As the traffic got denser I noticed the gauge started 'running' towards the 2nd dot.
If I carried on with my commute no doubt it would of hit the red. Past experience from owners with coolant issues virtually always states to never let the car overheat as the repair costs spiral! ... And so I did a U-turn and headed back home in clear air. The coolant temp quickly went down due to the rushing air. I parked the car at home and didn't drive it again.
A quick look on the diags revealed this:
... The electric fan sits in-front of the radiator and condenser, it provides additional cooling and is controlled by the DME. Most of the time it activated when AC is used... so this explains why I was having AC issues a few days ago.
After some in-depth reading on the Internet, it seems the number one culprit is the FSU (Final Stage) control unit which sits inside the fan shroud. Having checked the fuse (which was ok) I decided to enquire with the dealer about getting a replacement fan unit...
Going to the dealer to find out the cost of a new fan unit...
No Thanks!!
I managed to solve it using new parts, much cheaper - here's how...
The E46 Pusher Fan
Pusher Fan Replacement
Extra Info
Bumper Removal DIY:
http://www.m3forum.net/m3forum/showthread.php?t=247135 - Thanks Obi
http://www.bmw-planet.com/lib/BMW_e4...Bumper_DIY.pdf - Thanks DaytonaViolet
E46 non-m3 pusher fan
The fan setup on the e46 non-m3 cars is a little different, some have puller fans so you need to be careful here. I'll include the part numbers:
P/N: 64546922554 or 64546988913
Going for new fan parts or old?
This is subjective. If you really want to make a huge saving you could buy used parts. Having gone through this I'm glad I used newer parts as its likely they'll last longer and this is not something I want to DIY anytime soon - spent all weekend on it!
In Conclusion
Although my issue is fixed I'm not stopping here. My car has 70k miles, and so I'm going to the following replaced soon:
- Coolant Temp Sensor (hose near fan)
- Thermostat
- Water pump
- New clutch for mechanical fan
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