No oil circulating through oil cooler on 89 R100RT.

[dougfollett]

After a 16-mile warm-up ride in 80+ weather I noticed the oil cooler on my '89 R100RT was stone cold. My shop manual shows some kind of spring-loaded valve down next to the oil filter. Is this valve possibly stuck? Any ideas how I should approach this?
Steve

Just talked to the airhead guy at local BMW dealer. He said no worries; the thermostatic valve doesn't open up until the oil gets REALLY HOT.

 

[BRICKRIDER]

After a 16-mile warm-up ride in 80+ weather I noticed the oil cooler on my '89 R100RT was stone cold. My shop manual shows some kind of spring-loaded valve down next to the oil filter. Is this valve possibly stuck? Any ideas how I should approach this?
Steve

Just talked to the airhead guy at local BMW dealer. He said no worries; the thermostatic valve doesn't open up until the oil gets REALLY HOT.

If I understand you correctly, you would not be posting this issue unless you noticed something amiss; i.e. you expected the cooler to be functioning by that time, and it wasn't.

Sorry, but I just don't buy the "no worries" business that you've been told. I believe that you are correct in being concerned.

I had a cooler on a 1983 R100RT. It did the same thing. Turns out that the piston inside the main cavity was stuck in place because of a bunch of "sticky goo" plugging the whole cavity. I had purchased the cooler as a kit, because the RT was a conversion from a /7. This was the external unit that replaced the regular oil filter cover. Hopefully yours is the same type? My comments are based upon this assumption.

That "goo" I believe was shipping protectant for the boat trip over salt water from the fatherland.

You need to take that piston assembly completely apart, clean it all up, and feel in the cylinder area with your fingers to make sure there are no metallic burrs inhibiting piston movement. If there are any, they need to be sanded smooth with wet/dry sandpaper at about 400A grit. You can look up and print the parts diagram on Max BMW website or others.

Don't be afraid of this. It's not rocket science. Once you have it apart you'll see how simple it is.

Ride Safely,
BrickRider

 

[47512]

Did you check the oil temp? The thermostat dose not open till about 195 degrees. I installed a kit I bought new from BMW, on a R75/6 25 years ago and it works perfectly. There is a tool that comes with the kit to open the thermostat manualy for initial filling on start up. It is nothing more than a 6x30mm bolt with a longer hex for the wrench, std hardware store stuff. There is a 6mm bolt and washer on the bottom of the thermostat, that is removed and the longer bolt installed, you don't need to screw it in all the way just enough to lift the piston so the oil can circulate, run the engine for a few minutes, shut the engine off, remove the long bolt, replace the short one with washer, and you are ready to go. This would probbaly unstick a stuck piston as well. The depth of the oil filter tube is important as oil can leak inturnaly if it is installed too deep in the case. On the older machines that had a gasket under the outter oil filter cover, don't use this gasket with the thermostat, the big white oring dose the job. Put the metal shim in first, then the white oring, the small oring can be held in place with a dab of grease on the thermostat. On later machines BMW eliminated the thermostat and used a cover with a caliberated hole, and it was easer to change to change the oil filter.


Ken G.

 

[lkchris]

After a 16-mile warm-up ride in 80+ weather I noticed the oil cooler on my '89 R100RT was stone cold.

Normal behavior. As designed.

Try running 80 mph for about 10 minutes. That will do it.

Heat is generated by doing work, and putting around isn't. Running 80 against all that aero drag is.

 

[lkchris]

On later machines BMW eliminated the thermostat and used a cover with a caliberated hole, and it was easer to change to change the oil filter.

On R100GS, that is. Because there's no frame clearance for the thermostat.

RS/RT used the thermostat until the end.

 

[88bmwjeff]

On R100GS, that is. Because there's no frame clearance for the thermostat.

RS/RT used the thermostat until the end.

The R100R and Mystic use the same set up as the GS. Some people have retrofitted the none thermostat plate when their thermostat needed replacement. The upside is that there's always oil running through the cooler. The downside is that there's always oil running through the cooler. If you live in a warm environment then the none thermostat mod may be a good idea, but it will take longer for the bike to warm up. If you ride in a cold weather a lot, then you may want to keep the thermostat option since the bike will warm up a little quicker.

That's my $0.02.

FWIW, I live in the SF Bay Area, and if my thermostat needs replacing, I'll probably retrofit the non thermostat plate to my RT.

 

[dougfollett]

We just finished up a 1,300 mile road trip with the R100RT and it ran like a champ. Except for a mid ride battery change it was flawless. We did a loop from Olympia WA, over Mt Rainer, south through Yakima WA to Dufer WA where we went white water rafting. On further south to Crater lake and then out to the coast where we hit the coastal weather and got rained on for the final leg back to Olympia. The last day was a bit of a slog with tourist traffic but the rest was Spectacular, car free riding. Thanks for the comments.

Doug