Oil cooler fan thermostat switch

[Chester RT]

I'm in the process of retrofitting an RT-P oil cooler fan to my 2005 R1200RT. I've found a supplier that can supply thermostatic sump plug switches, the problem I'm having is that I cannot find the switching thresholds to order the correct switch. I'm hoping that the combined expertise on here can point me in the right direction!!

Thanks Guys

[dirtrider]

I'm in the process of retrofitting an RT-P oil cooler fan to my 2005 R1200RT. I've found a supplier that can supply thermostatic sump plug switches, the problem I'm having is that I cannot find the switching thresholds to order the correct switch. I'm hoping that the combined expertise on here can point me in the right direction!!

Thanks Guys

 

 

Afternoon Chester

 

Now there is tough question to answer.

 

In the hexhed engine the oil sump plug area is probably one of the cooler places for oil temperature. This can complicate the selection of an oil sump plug fan switch.

 

Normally you would like to see your oil operating temp above 180°f-190°f (82C to 88C) but below 275°f (135C) but that is the operating temperature in (most) of the system not the lower sump area.

 

Seeing as the hexhead is a boxer engine that is oil/air cooled the oil cooling circuit oil temperature will be way higher than sump plug area.

 

So at this point it is guess based on the above--

 

I think I would set the switch turn on point to around 250F (121C) then depending on the switch design maybe have it turn off if the oil temp drops to around 240°f (115C)

 

To do it correctly a person should probably drill the oil drain plug for a thermocouple then monitor the oil drain plug temperature vs dash oil temp gauge reading then use the thermocouple numbers to pick the correct fan switching points.

 

My personal opinion is that the hexhead really doesn't need an oil cooler fan as they just don't get that hot in operation unless allowed to high idle in place for extended time. What the dash gauge shows is the cooling oil temp AFTER it picks up engine heat but before the oil cooler removes that heat.

 

Most riders that add an oil cooler fan to a civilian BMW just adds a manual fan switch to be turned on for parade use or excessive time in stop & go traffic. The police bike needs a thermostatic fan control as the officer is likely to be away from the bike for extended periods with the engine remaining running to run the lights, radio, other police accessories & the hexhead has a voltage monitor in the computer that bumps the engine idle speed up if the system voltage starts dropping.

 

 

 

 

 

 

 

 

 

Edited March 28, 2018 by dirtrider

[mwood7800]

I bought an adjustable controller. The probe slides in oil cooler fins. Mine has been on the bike for the past 4 years. I also have a manual switch on the dash. I think I bought it at jegs. Unless your thinking you might leave it running in the garage just go with the manual switch. The only time my fan has ever activated is when I test it.

[Chester RT]

Thanks for the replies guys. The reason I'm fitting a fan is because my bike is really sensitive to high temps. Any more that than 15-20 mins in stop-start slow moving traffic the temp starts to go up and the timing chains start to rattle and eventually knock. I had an independent BMW center check the timing chain and all checked out, they also upgraded the tensioners. They also checked the fueling, timing and valves, all ok. I'm also running 20w-50 oil.

 

To be fair my bike is mostly used for touring and days out, so its not a regular occurrence, only in traffic jams and heavy city traffic. This summer I'm touring Spain with a few friends and thought it would be prudent to fit a fan.

 

I'm definitely going to check out the the oil temps in various parts of the system as suggest by Dirtrider, and many thanks for giving me a stating point (121C on - 115C off) to work from. The use of a variable controller will definitely help here thanks to mwood7800 for that one.

 

I'll check this out after the Easter break and let you know how it went (i'll include the temp data as well).

 

Many thanks guys!!

 

 

[AndyInLZ]

I've just gone with the simpler on/off switch and rarely use it unless I am in stop-and-go highway traffic on hot summer days. For the Chicago locals on the board, think the Kennedy expressway at 5:00 on a hot summer day.

 

The switch housing is a BMW part that mounts inboard of my LH grip switchgear. The housing has room for 2 switches (I recall it is a police part).

 

It is impressive how quickly the fan cools off the oil.

 

 

[mwood7800]

If you get bored with the power band check this out. I have the same bike. http://advrider.com/index.php?threads/finally-fitted-lennies-rocket-sprockets.636838/