Problems with thermostat oil cooler install...

[KHEEREMA129911]

I decided to fit an oil cooler to my r90/6. and ran into some problems.

1) Oil lines were too short for me to mount the cooler to the crossbar under the triple tree. I guess the cooler was made for a newer model that didn't need longer lines?

2) After fitting the new oil delivery tube, and longer oil filter, I'm getting a knocking sound from the engine that wasn't there before. The oil light is not turning on though, and there's plenty of oil in the crankcase.

If anyone can help me with this, I'd appreciate it, I followed Kent Christiansens write up on the install on airheads.org. I believe I have all the o-rings in place right, but the white o-ring that came with the filter kit just seems out of place, it doesn't want to stay on the thermostat like it should...

I'm thinking of just scratching this whole assembly, but would like to have it work : (

 

[NEALART]

Could you post a link to the airheads.org instructions you followed?

I just sold my /6 and bought a 1981 RS with thermostat, so I might have some insight.

 

[sumran]

I have the oil cooler on mine, but have considered getting rid of it. Unless you have full lowers or ride with loads you probably don't need it. It makes oil filter changes a bear if you don't have the modified header. I kept mine because I live in Florida and do two-up riding with gear on occasion.

The white o-ring needs to be compressed but not too much. There is an o-ring article by Oak on the airheads site that goes into great detail about how to get the correct amount of o-ring compression. If it is not installed properly you can get too much or too little oil pressure. There are various filters available. Not all hinged filters are the right length for the cooler. I don't have the part numbers with me.

You will probably need to fabricate a mounting bracket, since you are putting it on a 90/6. It is designed to mount on the cross member that was addded on the /7's. I had to make one for mine when I added my fairing. It won't be the same on yours, but some variation will work.

Good luck.

 

[BOKRIJDER]

I had the same experience with a R90S in Europe years ago. The oil cooler kit thermostat assembly would not work on this particular bike. Pressurized oil would leak back into the sump rather than following the correct path with the cooler kit installed.
I had a couple of dealerships look at the engine oil filter housing cavity and the kit components. (including a dealership which had supplied and serviced the national police with bikes during the period the bike was built) The cavity configuration was slightly different than any they had ever seen. Their conclusion was that BMW had either made a mistake in the machining process or the case was reworked and placed back on the production line - no question that the anomaly was factory related.
My original problem was a very hot running engine at sustained, as in burn off a tank of fuel without slowing, 130 km speeds coupled with high ambient temps. - oil consumption would skyrocket. The oiler cooler kit was installed in hopes of lowering the engine temperature. Ultimately, I scrapped the project and added a deep and finned aluminum oil sump. It then seemed to run a little cooler, but possibly more important the extra oil capacity yielded a buffer against a low oil disaster.

Motard

 

[brownie]

Thermostat????

If memory serves...I've heard of some folks REMOVING the thermostat, a la GS...I believe you might have to be careful with cold-start oil pressure, but I think it could be doable........gurus/techies input??????

 

[KHEEREMA129911]

I have the oil cooler on mine, but have considered getting rid of it. Unless you have full lowers or ride with loads you probably don't need it. It makes oil filter changes a bear if you don't have the modified header. I kept mine because I live in Florida and do two-up riding with gear on occasion.

The white o-ring needs to be compressed but not too much. There is an o-ring article by Oak on the airheads site that goes into great detail about how to get the correct amount of o-ring compression. If it is not installed properly you can get too much or too little oil pressure. There are various filters available. Not all hinged filters are the right length for the cooler. I don't have the part numbers with me.

You will probably need to fabricate a mounting bracket, since you are putting it on a 90/6. It is designed to mount on the cross member that was addded on the /7's. I had to make one for mine when I added my fairing. It won't be the same on yours, but some variation will work.

Good luck.

Sumran- Thats exactly why I want to use one, its 95+ here in Austin basically for the next 4-5 months, and i do some 2 up riding with luggage for long stretches. I'm relatively sure I have the right filter, the bmw parts guy has a 90/6 and he has been very reliable and knowledgeable in the past with parts...he seems to be familiar with this modification. Its definitely longer then the stock filter.

The one thing that perplexes me, is that the white O-ring that fits onto the thermostat housing, that bolts to the case, that O ring doesn't really fit against anything in my opinion to really seal anything. The white o ring just kind of waffles in there around the end of the filter, because the round cut out on the case for the filter assembly to be inserted is bigger then the O-ring. It seems like the edges of the white o ring could easily bend in, just from assembly, because its not really squeezed between anything. To me it doesn't make sense that this filter is just kind of loose in there??????

If I can figure this out I'll have to make brackets like you did, very nice...

Does your white O ring mate up against anything on your bike??? I'll look for that tech article...

 

[KHEEREMA129911]

Found the tech article:

"The original filters were semi-sealed to the inner side of the metal cap cover and to the far inner end of the canister, via two small rubber O-rings, that lightly push fit over the central oil tube. These now obsolete O-rings were normally replaced at each filter change, and removing the innermost one was done with a bent end of a straightened coat hangar. If you are working on an early model Airhead, do check that those old small O-rings are NOT PRESENT; as they are obsolete, and NOT used now."

My bike had a small black o-ring around the base of the oil delivery tube, right where it screwed into the case, and I did put that on the new longer delivery tube, but is this article saying to remove that o ring, because the new filters have the small rubber o ring attached to the filter??? Even if I scrap this thermostat, I'd like to know if I'm suppossed to remove this oring.

 

[sumran]

Sumran- Thats exactly why I want to use one, its 95+ here in Austin basically for the next 4-5 months, and i do some 2 up riding with luggage for long stretches. I'm relatively sure I have the right filter, the bmw parts guy has a 90/6 and he has been very reliable and knowledgeable in the past with parts...he seems to be familiar with this modification. Its definitely longer then the stock filter.

The one thing that perplexes me, is that the white O-ring that fits onto the thermostat housing, that bolts to the case, that O ring doesn't really fit against anything in my opinion to really seal anything. The white o ring just kind of waffles in there around the end of the filter, because the round cut out on the case for the filter assembly to be inserted is bigger then the O-ring. It seems like the edges of the white o ring could easily bend in, just from assembly, because its not really squeezed between anything. To me it doesn't make sense that this filter is just kind of loose in there??????

If I can figure this out I'll have to make brackets like you did, very nice...

Does your white O ring mate up against anything on your bike??? I'll look for that tech article...

It is important that the o-ring is compressed. There should be a metal shim installed before the o-ring. This is for protectection of the o-ring and to get the spacing right for compression. Too little compression (more common) or too much compression (less common) are both bad. In most cases, you will not use the paper gasket on the cover.

This article may help. There are many others out there. When you remove the o-ring it should be flattened from compression.

http://www.airheads.org/content/view/189/49/

 

[boxerkuh]

I live in South Carolina and have researched this process. My research was not scientific, but here is what I found out on my bike:
1. Ran synthetic oil - no oil temperature change
2. Added a deep oil pan (added 1/2 qt capacity) - no oil temperature change
3. Added a another spacer oil pan ring (now added another full quart) - no oil temperature change
4. Added a new oil cooler - now the temperature dropped significantly

I was not able to mount a thermostat, due to running Supertrapp 2:1 exhaust (the supertrapp run closer to the frame). I have never had any issues with it. I after some time took the spacer oil pan ring off and sold it. I bought a RR oil-temperature stick from Germany which is 100% accurate. I checked it several times to verify it in boiling water..... and you know what Oak says about the oil coolers - he loves them.... My two cents, anyway.....

 

[NEALART]

Found the tech article:

"The original filters were semi-sealed to the inner side of the metal cap cover and to the far inner end of the canister, via two small rubber O-rings, that lightly push fit over the central oil tube. These now obsolete O-rings were normally replaced at each filter change, and removing the innermost one was done with a bent end of a straightened coat hangar. If you are working on an early model Airhead, do check that those old small O-rings are NOT PRESENT; as they are obsolete, and NOT used now."

My bike had a small black o-ring around the base of the oil delivery tube, right where it screwed into the case, and I did put that on the new longer delivery tube, but is this article saying to remove that o ring, because the new filters have the small rubber o ring attached to the filter??? Even if I scrap this thermostat, I'd like to know if I'm suppossed to remove this oring.

Yeah, they are saying there should no longer be a small black o-ring way inside at the base of the tube because the filters have them attached now.

 

[bmwwrench]

Oil Cooler Problems

Did you replace the oil filter cannister with a /7 type when you added the cooler? Without this change most, if not all the oil pressure will leak into the sump.

 

[KHEEREMA129911]

Yeah, they are saying there should no longer be a small black o-ring way inside at the base of the tube because the filters have them attached now.

THANKS!! Took it off!!

 

[KHEEREMA129911]

Did you replace the oil filter cannister with a /7 type when you added the cooler? Without this change most, if not all the oil pressure will leak into the sump.

No, just the longer delivery tube, with no holes. And this would explain why the white O-ring isn't compressing against anything...hmmm...that would make sense, I guess the /7 canister is longer? Anybody have one? How hard is it to replace?

 

[R90S]

No, just the longer delivery tube, with no holes. And this would explain why the white O-ring isn't compressing against anything...hmmm...that would make sense, I guess the /7 canister is longer? Anybody have one? How hard is it to replace?

I have. If you didn't do this step, you should not start the engine.

I did the job with the engine in the frame. Drop the pan and you can see the filter housing. Put a couple of strap clamps around it and use this to drift it out. Clean the recess and install the new one with appropriate locktite. Make certain that you seat the new one the correct depth, and don't damage the lip.

 

[NEALART]

Geez, what a great looking bike!

 

[bmwwrench]

Oil Cooler Problems

The "good" news in all this is that the latest (since '85) cannister has a wide flange at the outer end so no shim should be needed-if you get the depth right. This job is best accomplished with two people; one to man a torch in the appropriate area and the other to R&R the can. I'd suggest an oil pressure test when you are done with the installation to determine whether you've done any damage to the bearings. Since your oil light did not come on, you might consider replacing the switch.

 

[R90S]

All,

Some more information on the oil filter tube replacement:


I have both tubes in hand:

The difference in length is 13.8mm.

You can see the lip redesign on the new tube, on the right with the part number sticker attached. The tube on the left was removed from the block on my 1976 R90S.

Here is the old Snabbkatalog page:

It's item 10, described as "Steering Column Jacket" (I'd like to hear the explanation of that one).

Please note that the part number has been superseded from the old catalog page: you will receive the part as shown in the photo.

You need to R&R this part in order to install the oil cooler on a /6.

Ask your "knowledgeable" parts guy if he has ever done the job.

 

[KHEEREMA129911]

R90S- Well, I can't argue with that picture! Thanks for that info, I'll put an order in for that correct filter tube/housing. Thanks for the part # too!