Re: K75 Temp Light Always On

[Steveboot]

In previous posts I recounted my testing and final repair of the problem (thanks for all the help) but I hadn't gotten the opportunity to really test it. When at last I got a good ride in the temp light stayed off, until I was home sitting in the garage and decided to let her run for a bit with no cooling from the wind. Short story long, the light started flickering and I could not hear the fan.

Since that ride I have been in the process of moving homes and between getting the old house ready for sale and the new house habitable, the K has just been sitting. However, I figured the problem was most likely either the fan or the thermostat so I ordered both from Holland. With them now in hand, and my to do list for the house not so long, I figured I'd put down the paint brush and replace them both. It would be more educational to replace one at a time, but I don't want to dump the coolant twice.

The big question now is how to make this job easier? If I remember correctly removing the radiator was hindered by the tight space. Anyone have some guidance on how to do this in a straight forward manner? I was thinking pulling the fender and front wheel off first would solve the tight space issue but may be overkill. 

[Edward]

I did the same thing a few months ago. I removed the fan for a thorough cleaning, followed by a 12V spin test. Nothing about the removal process stands out in my mind as being particularly difficult.

At the time, Samco hoses were installed, but the side rubber shock mounts arrived late. Replacing those was a huge PITA with the radiator still in place after servicing the fan. I replaced all the rubber components. The thermostat was replaced after a thorough cleaning and flush. I also replaced the radiator cap, since mine was from 1987; that prompted me to address the cooling system in its entirety.

I use Engine Ice. So, as I said, it was a straightforward and easy job. Fender removal is simple. Keep in mind that it may have been easier for me because I like removing the fairing pieces. With the Samco upgrade from the original hoses, removing them was necessary.Just get into the process once you’ve ordered and gathered all the parts for a one-and-done job, rather than the two-part process I went through. Oh yeah, I also cleaned the reservoir and added the Samco overflow hose, trimmed to size.

[Laitch]

Post a photo of your Brick, Steve, and put its model in your Signature, too, so we know what you're up against.

Replacing the fan was a nut and bolt operation with the radiator removed on my naked K. Coolant drained into a clean pan for reuse, cowl removed, water hoses disconnected, fan disconnected, radiator out, and Bob's your uncle. It could get slightly tedious with a full fairing.

Is it a coolant temperature sensor, or is it a thermostat you're installing?

[Steveboot]

I previously replaced the temperature sensor, which I remember was tough to get to. This time I'm replacing the fan and the thermostat.

After thinking it over I am going to do it in steps. First I'll replace the fan and see if it does the job. Then, if it doesn't I'll move on to the thermostat.

[Edward]

What you are about to do is very simple. Thermostats are inexpensive, so replace yours even if you think it is working properly. They do not last forever. The radiator cap is another key part of the system that is affected by age. Replace that while you are at it.

[Laitch]

Thermostats are inexpensive . . .

. . . unless they are Brick thermostats. They run from 70 to 100 USD. The thermostat is a durable part of a Brick's system. Mine has almost 100K miles because the coolant is changed regularly and the Brick is ridden often. If it's working, leave it alone. If it is a suspect for overheating, test it by placing it in a pan with water coming to a boil when it is closed and verify it has the correct opening temperature. If you remove it for testing, don't damage the perimeter gasket; replacement gaskets aren't common. If it's damage, you'll need to roll your own.

If Edward has a cheaper thermostat that has been working for him, perhaps he'll post the make and model of it in this thread.

Your Brick's fan is likely to have a corroded fan shaft, failed fan motor or corroded connector. Please keep us updated.

[Edward]

Thermostat716EDL   Radiator Thermostat - BMW K Bikes; 17 11 1 460 716 / EnDuraLast 1   $39.99
TEMPSENS-K197   Water & Coolant Temperature Sensor - BMW K75, K100; 61 31 1 459 197 / FAE 1   $39.99
TH-ORing718   Thermostat ORing - BMW K Bike; 17 11 1 460 718 / EnDuraLast 1  $4.00
 
    Subtotal:   $83.98
    Tax:   $0.00
    Shipping & Handling Cost:   $8.26
    Grand Total:   $92.24


pushing 200,000 miles.

[Laitch]

pushing 200,000 miles.

pushing that on the thermostat, the sensor or both?

For anybody who is interested, Edward's Thermostat716EDL is available at Euro Motoelectrics. The o-ring on the thermostat cover is included by EME at no charge right now

[Edward]

The thermostat crapped out on the way home from the MOA Vermont rally. I changed the sensor while everything was torn apart. The radiator cap needed to be replaced as well. There’s nothing like having hot engine coolant soak your leg while stuck in New York traffic.