K11 Owners Group

[Sonu]

Friends,

I have the lower fairing off my bike for the first time to do a coolant change. It went well but I noticed that one of the hoses is collapsed when the bike is cold (see picture).



After I take it for a spin the hose is filled out again. Is this normal or should I think about replacing the hose? I have the part already.



Just trying to avoid going through a coolant fill up again unless it is necessary. I have not seen any posts here regarding coolant hose changes. Bike runs normally and has ~40K miles on the clock.

If I do need to replace this hose, are there any tricks to getting the old hose out and the new one in (it goes through a narrow pass through in the engine area). Is there some finesse to this (grease the hose?) or is brute force the way to go?

Thanks,

Sanjiv
_________________
1997 K1100LT "Ziggy" _GarminGPS_Corbin saddle_K Guards _Hyperlights_Fog lights_Eastern Beaver Relays_Cee Bailey_4"speakers_Michelin PR4's_MoS2_Spiegler lines_TPMS_VDO

[wera32]

Hey Sanjiv, I suspect your radiator cap or perhaps the hose from your reservoir is plugged and causing the cooling system to draw a vacuum when it cools instead of drawing coolant into the system.
_________________
Paul - '93 K11/12RS (sold), 2002 R1100S BCP and '03 RC51 KOG 29

[Sonu]

Hi Paul,

Thanks for the quick reply. I think you're on to something. I loosened the radiator cap and sure enough the hose "filled out". I cant tell if the hose to the expansion tank is blocked. I cant see any visible kinks or disruptions.

So should I simply get a new cap and leave the existing hose in place?

Sanjiv
_________________
1997 K1100LT "Ziggy" _GarminGPS_Corbin saddle_K Guards _Hyperlights_Fog lights_Eastern Beaver Relays_Cee Bailey_4"speakers_Michelin PR4's_MoS2_Spiegler lines_TPMS_VDO

[max]

Hi - it will likely be the cap, easy way to check should be to monitor the level in the overflow bottle while topping up at the filler - the bottle level should rise as the excess drains down under gravity... no rise/draining, blocked (or pinched, more likely) overflow hose.

Cap is supposed to open at about 14psi pressure, letting fluid OUT... it's also supposed to open to let fluid back IN at about -.5psi suction, so if it doesn't do that, you're up for a new cap.

Also - replacing the hose - might not be a bad idea if you've already paid for the part, especially if the hose has some years on it, since they're not designed for sharp folding of the rubber and it'd be a real PITA for that hose to fail on a hot engine and drain the block of coolant!!

Good luck

Max

[wera32]

I'd blow air back through the line to the reservoir. That could be all it takes. Of course if that works you'll want to clean out whatever debris was in there. Probably wind up replacing the cap anyway but worth a shot.
_________________
Paul - '93 K11/12RS (sold), 2002 R1100S BCP and '03 RC51 KOG 29

[Sonu]

Thanks Guys,

I appreciate the support.

I took Paul's advice and blew air in through the overflow line that leads to the reservoir tank (disconnecting it at the filler cap). Then I topped off coolant, closed the system and ran the bike till fan came on.

The coolant level in the reservoir tank went up so the overflow line is now unclogged. I waited for the bike to cool and then took out the overflow reservoir. Flushing the container I found a lot of debris (looked like coolant precipitates).



Unfortunately the hose still collapses back down after the bike cooled down completely. I'm off to the local stealer to see if they stock a new filler cap. Sounds like it is not opening at -0.5psi suction as designed.

Max, I do agree with you that replacing the hose is the prudent thing to do. I just want to eliminate root cause of the original problem before I take this on. I dont know if it is going to be a PITA getting the hose through the "brick" block or not.

Please chime in if you have any additional thoughts.

Sanjiv
_________________
1997 K1100LT "Ziggy" _GarminGPS_Corbin saddle_K Guards _Hyperlights_Fog lights_Eastern Beaver Relays_Cee Bailey_4"speakers_Michelin PR4's_MoS2_Spiegler lines_TPMS_VDO

[CheapJapCopy]

My old K100RT often had this hose collapsed, easier to see as it's open to the air.. Doesn't seem to affect anything and it never overheats.
_________________
1992 K1100RS - Red and gold.

[Flying Duck]

I've never put one back on but I've pulled a few of them off. To get the old one though the hole, cut off the thick part of it that was on the radiator.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

[max]

Fitting the bottom hose isn't too bad (with a new hose, anyway). You've got to squash in the side of the top of the tube - so it looks like a "C" from the end that goes on the radiator - and work it through, then let it expand out to being circular when finished - I found an old rod (nothing sharp!) helped, as did some CRC 556 on the outside to make it easier to twist into and line-up in the hole. Might pay to check for oxidation deposits in the hole too, before you refit.

Been a long while, last did this on the first BMW, the 100RT...!

HTH

Max

[Sonu]

Guys,

Just wanted to report back that the bike is fixed and back to normal.

I finally received a new cap from the dealer yesterday. This solved the collapsed hose problem.

I went ahead and replaced the hose since it did feel soft and spongy. It was a very easy job. I did not even need to cut the old hose. One hard yank and it came right through. The new hose went in with the top of the tube squashed in a C shape as suggested by Max. First attempt worked.

I managed to fill the radiator in a single attempt. No need to burp it The trick of course is to fill up very slowly. I used a 1/16" aquarium air hose to siphon in the new fluid with gravity feed. Then I ran the bike to make sure that fan came on and topped off the reserve chamber. Try this trick and let us know if it worked for you.

Thanks again for all the hand holding

Sanjiv
_________________
1997 K1100LT "Ziggy" _GarminGPS_Corbin saddle_K Guards _Hyperlights_Fog lights_Eastern Beaver Relays_Cee Bailey_4"speakers_Michelin PR4's_MoS2_Spiegler lines_TPMS_VDO

[owrstrich]

right on sonu... way to stay with it...

now get your arse out there and get some ride reports posted...

the flat landers will appreciate it... me too... and let us know how the foil bubble blanket is working...

j o
_________________
yeeeeeehaaaaaaa...