Hi Don,
I always appreciate your info and experience you provide sir!
I'm just posting what info I have read and is printed that I used as my reference. This correlates to BaliDawgs post and why I posted it. But sure the Bentley Manual has been known to be incorrect sometimes (or vague). Look forward to your follow-up from source at Bentley what they say.
Pertaining to you were not able to find info in training manuals that cite what Bentley states. So were you able to find printed info directly citing your stance?

Just heard back from my friend Charles. Alas he no longer works for Bentley Publishers. he's now in the training arm of WTI. He did say he would try to help.

The later answer has frustrated me. I KNOW there's published material about mechanical/electric (primary/auxiliary) fans from old BMW School handbooks, I took the classes and received the books. Albeit I'm bereft of these any longer. Furthermore the TIS (real: my subscription) and the online version is missing such, and much more.

For example, the online TIS is missing instructions on how to replace a clutch on a SMG M3.

 

One way to see is it to log coolant, oil, and ATF temperatures with and without the electric fan plugged in. That clearly shows how critical it is. When the engine is at operating temperature and the car is still, the coolant temps will start rising with the electric fan unplugged.

 

that sounds like it would be a good indicator.
I would think BMW_North or Terra have this info already?
wish they would chime in with what they know.

so Bali you on vacation..noticed your “location” flag has changed.

 

BD - Full version of Electric Fan Guide here:

BMW-North Electric Fan Guide

BTW - interesting discussion. For many conditions such as idle or stop 'n go etc. a coolant temp sensor (CTS) signal of 85C to DME first activates the e-fan. The e-fan will remain ON until CTS drops to 75C (depending on other inputs i.e. speed, load etc.) although the PWM signal may vary during the ON period. The PWM voltage signal is reduced as the CTS value drops.

 

BD - Full version of Electric Fan Guide here:
BMW-North Electric Fan Guide

Thanks! I updated the link under IMPORTANT THREADS & LINKS.

 

The interesting question in this thread is not related to the OP's issue but to the question is the e-fan or the v-fan primary purpose to cool the engine. I think both sides are correct.

BMW in their SIB regarding the e-fan (attached) state that the v-fan is primarily for cooling the engine and the e-fan is to support AC operation. They also state, as it was pointed out earlier that the manual e46's (M3's excluded) only got a a single e-fan with dual purpose engine cooling/AC support.

However if you read carefully BMW is implying this SIB pertains mostly to the vehicle with a single fan... and that there may be a severe overheat condition if the "single" e-fan fails to operate. They then go on to state that the v-fan will cool the engine if the e-fan fails to operate (on models with both fans. I know this to be true when my daughters e-fan failed in her e46 xi and she continued to drive with only the v-fan.

So on manual non M's the e-fan is the primary engine cooling fan whereas on automatics and M's the viscous fan is the primary engine cooling fan.

Many have done the v-fan delete without issue - this is down to the brilliant logic of the DME logic. The DME will drive the e-fan more often and longer to maintain the mapped thresholds set in the logic. The safety net of the v-fan is traded by the by the benefits afforded a single easily replaceable e-fan. It's a risk management decision.

IMHO the e46 was sort of a transition chassis for BMW to move into advanced efficient cooling - ergo why some models needed both v & e fans. The e46 DME had a single cooling map and engineers determined that the additional load and cooling requirements for M and automatics required added cooling. Next generation saw the introduction of electric cooling pumps that much like the e-fan are driven by PWM signals based on multiple input sensors to optimise efficiency and or performance using 4 different cooling maps. Electric t-stats, around for a long time offered little control but now combined with e-pumps and e-fans offered superior control of coolant flow AND airflow to rapidly change the dynamics of the engine to suit a drivers needs immediately.

Happy motoring...

 

And a fine dance partner you are my friend.