New to the forum - Radiator fan replaced with Spal, possible fuel pump issue

[jonnyTHUNDERmaker]

Hello Gentleman,

I am new to the forum and a fairly new BMW K75 owner (love it)

I was having an overheating problem and traced it to the radiator fan motor wiring harness

Good news is I found the problem, better news is the fan motor is still good. Bad news is that that actual magnetic slides that touch the copper cylinder is where the problem was.

Now if I can just track down the actual wiring harness part of the fan motor that would be excellent.
This is what I need. Just the harness. Not the whole motor



Actually, this is all I need. Just this one little dang piece. From the brown wire to the copper coil and plastic housing.


I would rather not have to spend $70 and get the whole fan assembly

Thanks for your help
Here is the link to my thread from DoTheTon. Has all the info on stuff I have done to the bike so far
http://www.dotheton.com/forum/index.php?topic=37865.0

[sch]

I'm not sure if you can buy the harness as such. I'd just buy the fan motor from beemerboneyard or somewhere else who sells it.

[jonnyTHUNDERmaker]

Yeah. I know beemerboneyard has the motor, but it's $70. My hope is to find someone that replaced their bad motor and obtain the part I need from them for cheap.

[WayneDW]

Welcome Jonny,
I suggest you check out Duck's (Frankenduck) parts site here: http://www.kbikeparts.com/

If you don't see what you need, email him.  His email is on the first page of the site.

[jonnyTHUNDERmaker]

Thanks Wayne,

Ill look into that

[Photog]

The motor isn't very different from lots of other Bosch motors used for automotive ventilation fans or radiators. Even though the whole motor is fairly specfic to the brick's application the brush assembly may be common to various Bosch motors. You may want to check with an automotive motor shop, or if you have a good wrecking yard see if you can find a similar motor in a Volvo, VW, BMW, Mercedes, etc.

[rbm]

First question is what leads you to believe this part is the failing component?  Have you tested continuity from the soldering lug to the brush and found it to be open-circuit? 

If so, have you thought about trying to remelt the solder on the lug?  Or maybe replace the wire from the lug to the brush?

Lots of questions but maybe trying to salvage the assembly you have may avoid having to purchase a new fan motor.

You might want to download the "Heat Management" document from the downloads page on K100rtforum.com as it contains instructions on replacing the BMW fan with a modern DC brushless fan (will give you longer term reliability).

[jonnyTHUNDERmaker]

I apologize for my brief and somewhat vague description.  I did multiple tests with the fan and after careful examination I noticed the problem. The brush from the hot lead was severely melted, damaged, crooked, and in no way able to make contact with the actual motor. If you look closely at my second picture above (sorry its blurry) you can tell how disfigured the housing is from the meltdown.

Here is the good side. I noticed the silver clip and how centered the small copper coil and housing are.


Here is the bad side. No silver clip, I have no idea how that disappeared and how crooked and melted the housing is


Also the brush looked as if it was resting against the actual motor housing which would have caused the initial meltdown.

I may just go ahead and order the fan motor from beemer boneyard and have a spare. I really want to get back on the K75.

[wmax351]

Take a look in the alternate parts sticky in the lieberry. The motors are an ac condenser fan motor from a few older cars. should be availiable at Napa or whatever car place. or rockauto.com

[jonnyTHUNDERmaker]

wmax,

Thanks a bunch.  I will check it out. I was just at Napa a few hrs ago picking up my submersible fuel line.

[Rick G]

Try EME http://www.euromotoelectrics.com/BMW-Motor-Radiator-Fan-K-models-1983-1995-p/fan-k427m.htm

[jonnyTHUNDERmaker]

Gentleman,
Thank you all for your input. I appreciate it.

I think I have found my solution. I am heavily leaning towards replacing the entire fan assembly with a modern fan (Thanks rbm) I signed up on the K100rt and found the heat management info.

Looks like I can find a 7.5" Spal fan assembly for as much as just the OEM motor (around $70)

[frankenduck]

I've looked at those Spal fans before.  Let us know how it works out.

[Rick G]

Yeah I would like to know how you go as I get a bit tired of fixing fans over the years.

[jonnyTHUNDERmaker]

Gentleman,
I'll be sure to keep you informed. I just purchased the Spal 6.5" Puller fan from:

http://www.brightonracingproducts.com/65-Spal-Puller-Fan-20-002.htm

With shipping it was just at $50, so a tad cheaper than just the OEM motor. Should be here is a couple days. Thanks again for all the input.

[wmax351]

Sounds like a good purchase.

My Formula SAE team runs a SPAL fan on the car. Running 22 km in 100 degree heat, the temp never went above 80* C.

[frankenduck]

Just curious but why did you order a puller?  (OEM is a pusher.)

[wmax351]

I thought it was a puller. It blows air back to my legs when it runs.

[jonnyTHUNDERmaker]

Frankenduck,
I read that it was a puller fan. It pulls cooler air through the radiator.  A pusher would push warm air from around the motor into the radiator. I could be mistaken, I guess I will see how it works.

[frankenduck]

I  was mistaken. When I test them off-bike I usually do it face down and it pushes up (why I was thinking push) when that actually means it's pulling from the radiator.

[Rick G]

Don't worry Duck just keep taking that medication and can I have your bike when they cart you of to the home for the permanently bewildered. :hehehe

[frankenduck]

home for the permanently bewildered. :hehehe

I've already been to Australia.

 :neener:

[Rick G]

It's not permanent the man in a white coat said I'd get better :loopy:

[jonnyTHUNDERmaker]

Hahaha...Cool, glad that was cleared up. I was starting to second guess. Thanks gents. Hopefully the fan will arrive before the weekend. I cant wait to get back on this thing.

p.s. anyone know a good place to get the hose from inside the tank that goes from the fuel rail return (i believe) to the fuel pump filter spout. I am assuming a 1/4" submersible fuel line would work. A lawn mower shop maybe? I only need like a foot.

p.s.s: Its number 15 on the diagram below

http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51745&catID=16&catname=Fuel_Supply&bindName=FUEL_PUMP_FUEL_FILTER&bindCat=16_0809

Thanks

[rbm]

Just to confirm, the fan is a puller.  I wired my OEM fan up wrong once and experienced constant overheating problems with the engine.  It was like a positive feedback loop where warm air in the engine compartment was being forced through the rad, warming up the cooling liquid, ad infinitum.  Took me a few months to sort the problem.  A real DOH! moment when I solved it.

As for the fuel line, use any hose rated 30r10 for internal to tank useage.  Napa and other auto parts stores should carry that and sell it by the foot.  This is also useful reading:
http://www.napabeltshose.com/images/Barricade_Training_Final.pdf