[bobinyelm]

This is for my neighbor-

She suddenly started having her electric fan come on at full speed as soon as she switches the car on in the morning (engine dead cold 60 def F or so), and never goes off.

I read a thread where they said that is a frequent symptom of a failing water pump.

She states there is no Check Engine Light displayed, nor has the car ever exhibited coolant leakage, or any abnormal temperage reading.

The thread mentioned a faulty pump will frequently run the electric fan on high before it shows any real failure which doesn't make sense to me.

I have an Autel MK808MP bi-directional scantool that generally pulls manufacturer's proprietary codes

I have not yet hooked it up, but was looking for an opinion on whether it sounds plausible if a functioning water pump will cause the continuous fan problem, and what code if any should show up in memory.

Thanks,
Bob

[jadams161]

Failing or failed coolant pump. The fan comes on to save the engine.

[gunnerxq]

Yeah coolant pump. Replace the thermostat while you're there. How many miles?

[bobinyelm]

OP:
2006 e90 325i 136,000 mi

She asked me to scan her car with my Autel MP808 Bi-Directional scan tool, which I did.

First she backed it out of carport far enough to open door and hook to the DLC and the car started normally, ran about 20 seconds, and the fan came on full speed constantly.

Shut it down hooked up the scan tool and turned ignition on.

FIRST bad sign. Battery voltage 10.8 volts. I know these cars are very sensitive to weak batteries, but running the charge voltage was 13.9 volts, so the charging circuit is likely just fine. She only drives the car a few miles a week, and doesn't remember when the battery was last changed, so I put the battery on conservative charge (6 amps) and will check again after 15-20 hours for static voltage.

Scanned Vehicle for DTCs (No CEL was illuminated)

002EA1 Present BSD Message, Oil Condition Sensor Missing
002EE0 Present DME Coolant Temp Sensor Signal
002EFF Absent DME Electric Fan Self Diagnosis

Some Footwell Module faults for tail lights and stuff (did not investigate)

The coolant pump was very quietly running the entire time the IGN was on, engine not running (evidence coolant stream under coolant fill cap). Pump running too quietly to hear unless I put my ear against the uncapped (open) reservoir. Tried to operate at 50 and 95% using scan tool commands but no change in speed or sound.

NOTE: I depressed the accelerator pedal for 10 sec with the ignition ON (coolant bleed procedure)-the pump did not appear to running after that.

Tried to operate the cooling fan using the bi-directional scan tool at 50 and 95%. Showed only Fan Error when the command was actuated, and fan did not activate.

Would you still say the pump and thermostat should be replaced/

[bobinyelm]

RESOLUTION:

Owner took her car to local BMW dealer in frustration.

Turns out a rodent got up on top of the starter and ate wiring harness. There was NO evidence anywhere of anything living there, and zero mouse or rat turds anywhere in or under the car. No shredded insulation like I usually see with rodents, but I guess she's known the service writer for years and trusts him implicitly.

She wouldn't tell me the final bill amount, but said it required removing the intake manifold and many making spices to replace missing several sections of wiring. She admitted to over 8 hours labor being spent, plus they sold her a new battery and a bunch of under hood hoses.

They said her water pump is OK (thought at 135k miles may not have long to live).

She is now religiously mixing essential oil of peppermint and water w/ some dish detergent and spraying our joint carport so it smells like a candy cane factory hoping it won't happen again.

Thanks to those who replied with suggestions!

Bob

[The Nightman]

Thanks for the follow up. The waterpump would likely have fault codes if it was on its way out soon, so no worries there for now. Hard to believe it's still the original waterpump from 2006 and >100k miles though.

I had to deal with 2EFF by itself. The fan would fail self-diagnosis and run at full speed and the engine would go into limp mode as a precaution. Only a replacement fan would resolve it.

[bobinyelm]

Neighbor said she doesn't ever remember replacing the WP since she owned the car (it was 3 yr old under 50k when she bought it). She said biggest expense was $2100 for new motor mounts a couple of years back. Mostly under $1000 services.

But that car and her mother's car ('05 E350) keep them broke. Benz dealer recently got them for $3500 to basically replace one door lock assy that would bounce up and down when commanded to lock and needed a finger on the inside lock button to help it comply.

[The Nightman]

Originally Posted by bobinyelm

Neighbor said she doesn't ever remember replacing the WP since she owned the car (it was 3 yr old under 50k when she bought it). She said biggest expense was $2100 for new motor mounts a couple of years back. Mostly under $1000 services.

But that car and her mother's car ('05 E350) keep them broke. Benz dealer recently got them for $3500 to basically replace one door lock assy that would bounce up and down when commanded to lock and needed a finger on the inside lock button to help it comply.

Exactly why I would never advise owning an old German car if you can't turn a wrench. Sounds like they would be happier with Toyota/Lexus products

[opjose]

As many have discovered, myself included, the water pump can fail without you ever seeing a code before the car starts to overheat.

[bobinyelm]

Originally Posted by The Nightman

Exactly why I would never advise owning an old German car if you can't turn a wrench. Sounds like they would be happier with Toyota/Lexus products

I agree 100%

SO many people associate a German luxury brand with success and rewarding themselves with something special, not understanding they just threw themselves off the dock with heavy chains wrapped around their ankles. To admit the mistake and trade "down" to a more reliable car admits "failure" and loss of personal status to them.

During the 90s until last year I operated import repair shops and had a slug of 70s, 80, and 90s BMWs and MBs (as well as a few British sports cars from the 60s and 70s). I also had some newer MBs up through early 2000s R170 and W203 cars. These were all quite reliable and offered comfort, good ride and good handling, though cars designed after 2000 tended to be built to a price and offered belles/whistles features with complexity, over engineering, and reduced reliability. (The British cars were not reliable, but were easy/cheap to fix and a leftover addiction from my youth) Eighties BMWs of all series, and MBs of most series were among the most bullet proof ever made (Especially the W123 and W126 sedans) and were easy to keep on the road. Since then, they are rolling liabilities IMHO, though STILL nice to drive while well maintained (albeit it at hard to justify cost).

When I closed my shop and retired I sold my German cars and bought well used Japanese cars. Hondas, Toyotas, and Subarus because I was not about to pay people exaggerated sums to do what had been easy for me with the tools and equipment I had at hand, especially my service lift. The last month in my shop I did long term preventative maintenance on my Japanese vehicles (Brakes, suspension work, timing belts-basically anything I figured would need replacement in the next 50-100k miles) to preclude paying shop owners like I used to be. One exception is my wife, who LOVES Lexus SUVs and has a 2013 50,000mi RX350, but hey, it's a Toyota and reliable out of the box.

The neighbor I asked about and her mom have the BMW e90 and mom's E350. Neither is a "bad" car but they are paying for their reluctance to be practical, and I feel bad for them. They sometimes ride in my '07 Subaru Forester and remark how easy it is to get in and out of, and are amazed that with 170k it still feel "new" but I know they would never downgrade to something like that, though when I share that the PS pump, Alt, and AC Compressor is on top and can be changed in 20 minutes, and the starter in no more (vs the e90 that is a real PITA, but was a very profitable job for me a couple years ago) they smile but will cry in agony when that e90 starter job that costs $1300 and up and requires new aluminum bolts and intake manifold removal of brittle plastic parts.

But it's a choice a LOT of people make. Here in Phoenix where I retired the road is FULL of quite new BMWs and MBs.

"You pays your money and takes your choice," as a 30yr friend and fellow shop owner says. He was like me an aficionado of 70s-80s BMWs owning as I did 2002s, 3.0CS, a couple B9 Alpinas, e30 M3 , e28s, e32s, e34s, and a few 635CSi. Those M20 and M30 engines were things of beauty and good engineering and capable of 400k miles in gentle hands.

He pampers his customers driving pricey iron and says nothing bad to them about their choices (He is a BMW/MB certified tech but does the Aston Martins, Porsches, Maseratis and the few Ferraris living in Olympia), but his daily driver is a '96 Civic with almost 300k, an '03 4X4 Toyota Tacoma with almost 350k that's never seen a Check Engine Light, and yes, he has a mint 6 speed e36 Coupe he bought for pennies from a customer for fun, and builds clone Shelby Cobras for fun and resale (and nice summer drives). He could own any car he wanted (business has been VERY, VERY good to him), but he would not own a late model German car. Ditto say I.

Sad that German cars have become what they are today. They are not "bad," believe me, but they are not the simple stout cars they once were, either.

[G35POPPEDMYCHERRY]

i love how you guys call it the coolant pump.

pisses me off so much when water pump is used

[bobinyelm]

Originally Posted by G35POPPEDMYCHERRY

i love how you guys call it the coolant pump.

pisses me off so much when water pump is used

I KNOW!

I am waiting for those still using tems like "Master and Slave Cylinder" to be arrested and prosecuted for their thuggery!

Socially archaic and unacceptable terms like "mechanic" still prevail when automotive technicians regularly make $50+ per hour. Even my old FAA "Airframe and Powerplant Mechanic" aircraft certification are now is as insulting "water pump" moniker for the more sophisticate, computer-controlled coolant pump we now employ.

[The Nightman]

Originally Posted by G35POPPEDMYCHERRY

i love how you guys call it the coolant pump.

pisses me off so much when water pump is used

Ok boomer, my water identifies as anti-freeze and not coolant

[Grease23]

With a 50/50 mix "water pump" is half right, and "coolant pump" half wrong.

[G35POPPEDMYCHERRY]

^ haha very true