Done! Electric fan speed control...I'm not an electrician in any way, shape, or form

[workingonit]

I don't drive the X5 very often, only adding 1575 miles in the two days short of three years since I traded for it (under 1.5 miles per day), so it took me three weeks since I finished the fan speed controller install (plus the unexpected replacement of two failed switches) to actually road test it. The wife loves her Lexus more than she likes my BMW, so we use her car (with her driving 99% of the time), while my vehicles sit unused.

Anyway, I drove to my Dr. this morning, and tested the controller power level vs. noise level vs. coolant temperature, as I drove along in 30-50mph traffic.

• 1) the fan came on automatically at 75% power @ 175F, as I had set it to do, as I left the house, then
• 2) at the first long stoplight, I increased the fan speed to 85% when the coolant reached 194F (after which, the coolant moved down a bit to 188F), then
• 3) when the traffic thinned out, I reduced the power to 75% again, and the temperature remained relatively constant at 189-190F 'til I reached the Dr's office (the return trip, in 90F ambient, was done at 75% power, and 190F coolant temp)

As I stated in an earlier post, 75% power will be the new default setting for my fan, unless I desire to increase it as conditions may dictate in warmer weather...I probably won't go lower than 75%, even in winter, unless it gets really cold. At 75%, with the windows up, I can't hear the fan going, but at 100%, it roars. 75% power should reduce the airflow rating from 3000 cfm to 2250 cfm, which should be sufficient for my M54 under normal weather conditions.
from Summit Racing

I'll vary the fan speed as I need, balancing coolant temperature vs noise level, and more importantly, trying to extend the life of the fan by reducing its' usage. I intend to turn it off at highway speeds, if the coolant temp stays around 190F, so that will definitely preserve the fan for longer.

[BimmerBreaker]

Did you give any thought to just installing a stock PWN puller fan? I'm not sure if the E53 4.8is fan would have worked (4 wire whereas I believe earlier models were 3 wire), but an E60 or similar fan would have, either with very minimal custom fitting work or even bolt on if the fan motor fit the 4.4/4.8is puller shroud. Then you'd have DME control over the fan, varying based on ambient temp, engine load, coolant temp and other factors. If a single puller fan is enough to cool a 4.8is it's surely enough to cool a 3.0

[workingonit]

Originally Posted by BimmerBreaker

Did you give any thought to just installing a stock PWN puller fan? I'm not sure if the E53 4.8is fan would have worked (4 wire whereas I believe earlier models were 3 wire), but an E60 or similar fan would have, either with very minimal custom fitting work or even bolt on if the fan motor fit the 4.4/4.8is puller shroud. Then you'd have DME control over the fan, varying based on ambient temp, engine load, coolant temp and other factors. If a single puller fan is enough to cool a 4.8is it's surely enough to cool a 3.0

When I replaced the failing viscous clutch fan 2.5 years ago, I thought of getting a second Auxiliary fan (aftermarket, not BMW) to install in place of the clutch fan, by reversing it within its' own shroud, then connecting it to the existing PWM wiring, in order to do much as you've suggested. I have had little to no experience with BMW or PWM wiring, so I fell back into my comfort zone, and bought an electric fan from a manufacturer I'd used before. I've installed many on many vehicles, though never on a BMW. As for getting a BMW 3-wire or 4-wire fan from a specific model to use, it seems much easier to run standard fan wiring and only have to worry about getting a properly-sized fan with enough airflow that would fit in the vacated space.

I certainly would've liked to have the replacement fan controlled by the DME, but I didn't want to experiment and mess it up, or have both the replacement and Auxiliary fans fail to function, due to my efforts. So, after I considered making a motor controller (mostly under my control) do the same, without damage to the Aux fan's PWM wiring, I "redneck-engineered" a simulacrum, and added to my limited electrical knowledge base at the same time.

My wiring is a mess (it always is: I believe in function first, form second), but the system is working as I had imagined it, and was probably cheaper to build than if I used new or used BMW or BMW-aftermarket parts. Besides, I'm an inveterate tinkerer from way back, and had fun getting my Rube Goldberg-ian fan & controller assemblage to work!

[X5chemist]

Water flow is important too? Are you running a stock plastic impeller? Cooling on mine is better with a metal and 125,000 warranty water pump. If it's moving, 190F is a normal temp. The mechanical fan and auxiliary fan keep it cool in slooooowww traffic.

[workingonit]

Originally Posted by X5chemist

Water flow is important too? Are you running a stock plastic impeller? Cooling on mine is better with a metal and 125,000 warranty water pump. If it's moving, 190F is a normal temp. The mechanical fan and auxiliary fan keep it cool in slooooowww traffic.

As far as I can tell, the water pump is original (the unused fan mounting threads look ancient), but I haven't cleaned it up to look for a manufacturer or part number stamping on it.

At 210583 miles, it shouldn't be original, but the first owner seems to have maintained it well, and the second owner (who bought it specifically to semi-restore in order to swap for my Chevelle) didn't replace it (or the failing viscous clutch fan assembly), when he renewed the rest of the cooling system.

I haven't detected any seal leakage, shaft wobble, or the sounds it would make if the pump was failing, yet, but I'll clean it up, look for identifying marks, use my automotive stethoscope to listen to it, and then I can judge its' provenance and internal health better.

If and when I need to replace it, I'll be buying a Stewart water pump. I've used a few on previous trucks and on my race Chevelle (before I installed a Meziere 55 gpm electric pump), so as usual, I'll go with what I know (and trust).

Sent from my SM-G965U using Tapatalk

[kancho]

Sexy Womans from your town

[workingonit]

Originally Posted by workingonit

As far as I can tell, the water pump is original (the unused fan mounting threads look ancient), but I haven't cleaned it up to look for a manufacturer or part number stamping on it.

At 210583+ miles, it shouldn't be original, but the first owner seems to have maintained it well, and the second owner (who bought it specifically to semi-restore in order to swap for my Chevelle) didn't replace it (or the failing viscous clutch fan assembly), when he renewed the rest of the cooling system.

...If and when I need to replace it, I'll be buying a Stewart water pump....

As usual, I haven't been driving/testing my X5 (maybe once a month, because my wife drives me in her Lexus, usually, and it's the first drive I've done in over a month)

Originally Posted by workingonit

I don't drive the X5 very often, only adding 1575 miles in the two days short of three years since I traded for it (under 1.5 miles per day), so it took me three weeks since I finished the fan speed controller install (plus the unexpected replacement of two failed switches) to actually road test it. The wife loves her Lexus more than she likes my BMW, so we use her car (with her driving 99% of the time), while my vehicles sit unused.

I last drove on May 20, when the ambient temp rose to 90F (though it was only about 85F, at the time). The aftermarket fan came on automatically at 175F (as I had set it to do), and the coolant temp rose to 190F, when the thermostat opened, as usual, and the coolant temp dropped to 188.5F, with the fan controller set at 75%. At stoplights, I increased the fan speed to 90%, and the coolant never rose beyond 192F, that day.

Yesterday, with the wife at her mother's ranch for the week, I had a chance to fetch groceries & pet/feral supplies in the X5. It was hotter than the day of my previous drive, as the ambient temp rose to 100F (95F when I left the house), so I was closely observing the temperatures at which the fan came on, the thermostat opened up, high temp reached on the drive, and low temp after the thermostat opened...all were different than expected.

Yesterday's road trip events and observations:

• 1) the adjustable thermostatic switch turned on the fan at 153F instead of at 175F; maybe it needs resetting, or maybe I need to put insulation around the control box, because the heat underhood (from the sun beating down on it) might be affecting it,
• 2) the thermostat opened up after the coolant reached 195.4F, at the first stoplight (higher than usual), but by then I'd turned the fan up to 100%,
• 3) when the thermostat opened, and the fan at 100%, the coolant temp immediately dropped to 185F, which was lower than I ever saw in summertime temps,
• 4) the rest of my drive included testing fan control settings @ different road speeds and whether stopped or on low-speed roads or even on a 5 mile highway jaunt (75-80mph)...I was adjusting the speed controller to maintain under or equal to 190F coolant temps...I could easily reduce the temperature just by increasing the fan speed in increments

I'm not worried about the adjustable thermostatic switch starting up early (that's why I wanted an adjustable unit, so it could be fine-tuned), but the sorta-late opening of the thermostat (at 195.4F versus the usual 190F I've come to expect) concerns me a bit.

Is my T-stat sticking, or showing signs of premature failure? or is it my water pump not flowing as well as before? I know the differences in drive-to-drive measurements are incremental, but I don't want to have either fail suddenly. I hate surprises.

There are no outward signs of failure at all...no leaks, no noise, no wobbly pump shaft, nothing. Perhaps I'm getting OCD concerning my "fan/speed controller/cooling system"'s health, or I'm becoming anal retentive (excessive concern with trivial details) in my senior years.

[80stech]

The thermostat controls the engine temp and you are trying to control it with the fan and trying to make sense of temp readings from the engine coolant sensor compared to where the fan switch is located plus you have a map controlled thermostat, so couldn't have made it much more confusing for yourself if you tried.

[workingonit]

I forgot that the thermostat is electronically controlled (I guess I didn't look at the wiring closely enough...just assumed it ran to something else... need new glasses).

You're correct, the map controlled thermostat is something I never dealt with before, too many small & big block Chevys in my past.

I'm trying to regulate things best left to the DME, and overcomplicating things, as usual.

[80stech]

btw I had a '69 pontiac back in the day that I built up a small block 400 for With 327 heads (1.94s not 2.02 though) forged TRW pistons (compression was up there but I can't remember what it was) I bored the block with head plates at trade school (I was 18) Crane fireball cam and a big double pumper Holley. I had 4:10 posi diff and a 3000 stall converter and manual TH-350. Totally hauled ass!