Oil change W/Oil cooler

[Bigrider]

I have misplaced the screw device used to open the valve in my oil cooler on a 84 R100RS during oil changes. If the oil is drained from the cooler by unscrewing the banjo bolts, when put back together, will the oil cooler fill the next time the valve opens or will I be harming the system? Thanks

Dave H
San Antonio, TX

[easter85]

Please note; this is just my opinion. I have a BMW Factory Oil Cooler on my R80/7. If I had your problem and I needed to change the oil; I definitely wouldn't drain the oil from the cooler when I changed the oil. I would just change the oil and filter and forget about the small amount of oil in the cooler.

I don't think it is a good idea to be taking those banjo bolts in and out any more than you have to.

Also, if you drain the oil in the cooler you will have to wait until the engine gets to an operating temperature high enough to open the thermostat on the cooler before the cooler will fill with oil.

That small bolt that screws into the thermostat so that you can drain the cooler and also refill the cooler should be easily duplicated by obtaining the proper thread and millimeter size bolt at any parts house. Just don't screw the bolt in further than when you meet some resistance. Again this is just my opinion.

[Boxerkuh]

I have an oilcooler on my airhead, but don't have seperate turn on or off switch, as I don't have a thermostat.
Therefore, I only suggest that you change your oil regularily, as if you don't have switch.
Hope that helps....

[The_Veg]

Dump the thermostat- you don't need it, and filter changes will be so much easier without it.

[rinty]

Dave:

My local specialist prefers to drain the cooler by undoing the banjo bolts. Just don't overtighten them when you put them back in, and try to use new washers. Doing it this way will not affect your thermostat. I would not recommend using a different bolt to open the thermostat; just order a new bolt from BMW.

For now, it won't hurt to change the oil without draining the cooler and lines; they only hold 250 c.c. of oil.

Rinty

[Bob_M]

I went to my local BMW dealer to order the thermostat screw/tool and they had it in stock. I think it was less than $5.

Oil changes are a major pain. I have to remove the banjo bolts and take apart the thermostat to get it past the exhaust header. (New crush washers every time). This discussion has got me thinking about getting rid of the thermostat and connecting with a GS oil filter cover. I do live in a cooler climate than Texas, Any thoughts?

[28796]

Have you tried shimmimg the header pipe out enough so that the thermostat will clear? I've got a factory cooler kit on my R90/S left over from the days when I toured with a Hannigan. By adding a few washers under the header clamp at the motor mount & adjusting the header out abit I'm able to slip the housing in & out. I believe I may have ground down one area on the housing body also but it was minor.

[RandyB]

Both Oak and lkchris, as well as every other experienced Airhead I talked to say the cooler is necessary. I went through the whole drill of draining, new washers, etc. for what looked like about 3 oz. of oil. It'll take some more info to convince me to do that again. It gets hot enough in Arkansas to open the thermostat, so I know it isn't just sitting in there.

:drink Waiting to hear more about ditching the thermostat tho. I doubt I will since this place gets very cold about January and I don't want to run the engine too cold.

[Bigrider]

My take on the discussion so far is that it might be more of a concern to repeatedly remove the banjo connectors than to it is to have an empty cooler (to fill on the next opening of the thermostat). Since I have to remove the banjo bolts to get to the oil filter bolts, I'll have to live with replacing the banjo crush washers and taking it easy on torqing them back up. Not a major issue in my book.. Thanks for your insight.

Dave H
San Antonio, TX

[rkildu]

There is one other option that I use on mine because of tight clearances. I remove the three allen head bolts that hold the thermostat housing together and then drop the lower half of the housing. Just be carefull of the thermostat insert and the large "O" ring seal. If the insert falls out, it can be reassembled upside down. Then I unbolt the cooler and move the whole works out of the way. This just leaves the top shell of the cooler which has to be removed to get to the filter. I originally had Phillips screws holding this housing and replaced them with appropriate allen head screws.

It's a little messy, but the whole operation is messy. Of course I am not dealing with an RT fairing either, but I think there is enough slack in the hoses to still use this method.

It seems to work best for me.

Rod

[rkildu]

On the subject of the cooler in general:

I have a VDO oil temp gauge on mine. The sensor is in the oil pan drain plug. In the summer time the oil temperature will climb up to just over 180 deg. Then the cooler cuts in and temp will stabilize at 180 as long as I'm moving. Stopping through town or in slow traffic it will rise higher, but it cools again as soon as I get moving. In the winter time it never gets that hot unless I'm stuck in traffic, so the cooler usually doesn't open.

A few years ago riding through Arizona I ran across another BMW rider at a rest stop. He had the same rig on his bike, except his sensor was on the oil pressure line where the oil pressure sensor is on the engine left side. He was seeing the same pattern except he saw stable temps around 220 deg. The difference being the sensor location.

Bottom line, in the South/Southwest on a faired bike you need it in the summer time. Up north where it's cooler, maybe not.

Rod

[Bigrider]

Rikildu, is the sensor an add on? Whre did you get it from?

Dave H

[rkildu]

The sensor came in the package with the gauge. It is a brass replacement drain plug that has a through hole in the center that is tapped and the temp. sensor screws into that. A single wire clips to it and runs to the gauge.

I found the gauge package still in the box at a Motorcycle salvage yard that was in business here in town for a short time. That was many years ago.

Rod

[lkchris]

Bottom line, in the South/Southwest on a faired bike you need it in the summer time. Up north where it's cooler, maybe not.

Think it's more a question of HOW you ride rather than WHERE you ride.

The oil cooler is basically for sustained high-speed running. Think Autobahn.

As you know, aero drag increases with the square of speed.

Plus, the engine is turning more rpms and consequently producing more heat when you're running fast, and, of course, it's working pretty hard to overcome aero drag, etc., at high speed, as noted.

Think you'll find these factors much more significant than ambient air temperature and in fact think you'll find ambient air temperature has very little effect on engine cooling.

Think you'll also find very little problem with fairings, either. Instead the improved aerodynamics provided by a fairing may indeed give the engine a bit of a break as to how hard it's working.

Just hate the idea, however, of removing the oil cooler simply because it complicates oil changes a bit. Things like "chicken," giving up, path of least resistance, etc., come to mind.