K75 engine temp/cooling matters

Yup, I agree. I just was thinking that a quick pressure check would be quicker than having to keep checking the rad level and it would save dvandkq from having to worry that something is wrong. Maybe the coolant level just dropped on it's own, though I highly doubt it. Maybe replacing the hose and cap (since we know we had crud buildup) is a great idea that couldn't hurt no matter what. But if it were me, I'd be worrying about it until I was darn sure it is OK. KnowwhatImean?

I threw the question out there, hoping that one of the REAL K-Bike mechanics might comment on it.

I mean shotgunning a problem is a valid way of fixing it. Done it myself as a car mechanic way back in the 70's and as a Computer Geek since then. But if you can lay your hands on the right tool, why not?

98lee said:

If you just leave the cap OFF all that RAIN will keep your radiator topped off all year!!!!

(I was born in Seattle, but all that rain made me decide to move to California when I was three )

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That's funny! I was born in Southern California, and the best thing that ever happened to me was my family moving back to Seattle when I was 11. (Mom and dad were natives.)

I can't get enough of all the things all that rain brings - snow in the mountains, rivers in the valleys, water in the lakes and Sound - all the things that make it worth putting up with all those gray and damp days.

godzilla said:

Yup, I agree. I just was thinking that a quick pressure check would be quicker than having to keep checking the rad level and it would save dvandkq from having to worry that something is wrong. Maybe the coolant level just dropped on it's own, though I highly doubt it. Maybe replacing the hose and cap (since we know we had crud buildup) is a great idea that couldn't hurt no matter what. But if it were me, I'd be worrying about it until I was darn sure it is OK. KnowwhatImean?

I threw the question out there, hoping that one of the REAL K-Bike mechanics might comment on it.

I mean shotgunning a problem is a valid way of fixing it. Done it myself as a car mechanic way back in the 70's and as a Computer Geek since then. But if you can lay your hands on the right tool, why not?

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I've only owned the bike for five months. Almost all of the riding I've done since getting the bike has been done in relatively cool/cold weather (nothing over 60, not many days over 50). A super slow leak would take a while to manifest itself. It's entirely possible the bike came to me with a low radiator level and it's just taken five months for the problem to get to the point where there are now symptoms. I'm the third owner of a 16 year old piece of machinery - anything is possible!

I'm actually enjoying getting my hands dirty working on the thing. I've never considered myself mechanically inclined until I discovered how easy it is to follow the simple instructions in a good shop manual. If I can fix it in my garage some evening, it saves me not only money, but the day or two I'd have to spend without the bike - and commuting by bus - yuck!

I really don't have any objection to replacing the radiator cap and the tubing between the radiator and the expansion tank. The parts are cheap, access to the work area is fairly easy, and results should be easy to determine.

Now if we're talking about a valve adjustment, or a clutch replacement, or a radiator replacement, I'm going to go see my wrench.

dvandkq said:

That's funny! I was born in Southern California, and the best thing that ever happened to me was my family moving back to Seattle when I was 11. (Mom and dad were natives.)

I can't get enough of all the things all that rain brings - snow in the mountains, rivers in the valleys, water in the lakes and Sound - all the things that make it worth putting up with all those gray and damp days.

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My brother moved back to that area 6 years ago after living in Sacramento. When I went to visit him (on San Juan Island) last September, I was really impressed with how green every thing was in Seattle, Anacortes(sp?) and on the islands. The smell of the salt air mixed with the smell of all the pine trees was incredible! It was gorgeous all week. It made me envious right up until the Dec.-March weather reports. Hey, I got to kid you, I'm from there!

Keep us all up to date with your Brick. We're curious to find what it was. (but my money is still on the overflow hose) But , then again, that might be why I always come back with empty pockets when I go to Vegas.

I'm just happy that I actually got one right!!! Starting to scare myself!

Thanks to your encouragement and my Clymer's manual, I was able to easily remove the tank, tool tray, fuel control computer, battery and expansion tank.

Then I pulled the tube connecting the radiator to the expansion tank and pressure tested the hose and the expansion tank - all was fine. I cleaned out the inside of the fitting on the radiator filler neck the hose connects to and removed some gunk.

I topped of the radiator with about a cup of coolant and then put it all back together.

I started the bike and almost immediately coolant started dripping from the bottom of the chin spoiler. I traced the leak up and discovered there is a hole in the radiator. I think it's a safe assumption that all of my problems trace back to a small hole in the radiator. Based upon the relatively sudden onset of symptoms, I'm guessing it happened very recently.

I know it's all dependent on the size of the hole, but I'm wondering if Stop Leak or equivalent is a good first step in my attempts to plug the leak. Is Stop Leak not recommened for aluminum motorcycle engines? If Stop Leak doesn't work, then I'll likely need to replace the radiator, but I'd like to try the $5 solution before I move on to the $500 solution.

I wouldn't use stop-leak or any other product that attempts to seal from the inside.

However, I have used a Permatex product.

The Permatex item number is #80884.
The product is called "Gas Tank and Radiator Repair"
The product is also known as GTR-1

It comes blister packed on a blue card and looks like a 4 inch black rubber cigar.

I drained my radiator when I did the repair to make sure everything was dry. I also used a toothpick to push the stuff inbetween the fins.

That was almost two years ago.

YMMV,
Eric

Is Stop-Leak going to harm the cooling system, or is it just likely that this attempt will fail?

dvandkq said:

Is Stop-Leak going to harm the cooling system, or is it just likely that this attempt will fail?

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I used that crap in my pickup truck one time for a pin hole leak. It didn't fix the leak and the truck started running hot. A mechanic buddy of mine told me that the Stop Leak may plug the hole, it may not, but it may also plug the radiator itself. He siad that he wouldn't use it. Ended up replacing the radiator.

Maybe take the radiator to a a radiator repair shop to see if they can fix the leak. I've done that with old cars in the past with good results. if that works on a bike.

You might try looking for a radiator off a wrecked bike or one that's being parted out. I found a good, used instrument cluster that way. See http://www.engelandmoto.com/index.html

Seemed like a nice enough guy and he'e an MOA memeber.

Beemerboneyard.com has a couple of used K75 radiators on their site for not too much money. I'm just trying to avoid having to remove and replace the radiator. That's a lot of fairing parts to remove and piece back together.

Just to close out this thread, I think I've decided to have my 'wrench replace my radiator. I'll ask him if he's okay with me finding a used radiator for him to install.

I was just reviewing the Clymer's manual on removing/reinstalling the radiator and there are a lot of hoses attached to that thing. On a 16 year old bike, I'd prefer to have a trained eye looking those hoses over for wear and damage and replacing whatever needs replacing.

I'm sure it will cost in the neighborhood of $300 for the parts and labor, but I think it will be money well spent if it revitalizes the cooling system.

dvandkq,

Lost another bet! No wonder I never come back from Vegas with any money.

In all your posts, including the one after you filled the radiator for the first time, you never mentioned seeing any fluids on the ground after a ride. ( Or was it because all that "Natural Seattle Fluid" obscured the puddle?)( again , just kidding)

I'm glad you found the root of the problem. I concure, don't try any sort of stop leak inside the system. Most of them will put a gunky film inside the whole system which can hurt the heat transfer. Alumaseal is one product that will not do that, but it is still a temporary fix. You don't want to be 100 miles from anywhere and have the radiator start leaking again.

Like Godzilla said, look for a good used one. I've had very good experiences with Phil Engel at the site Godzilla recomended.

These are all guesses, but I think the reason there was never fluid dripping from the underside of the bike before I filled the radiator was because there was never enough fluid in the radiator to rise to the level or pressure required to squirt the coolant through the hole.

I think that perhaps the cold November - March weather kept things cool enough where the bike didn't need the full capacity of the cooling system. Now that things are slowly warming up, the problem manifests itself.

I'm positive I would have noticed a puddle of coolant under the bike in my parking garage at work, and there are no coolant stains on the concrete under where I keep the bike in the garage at home, so it appears there hasn't been any leakage for as long as I've owned the bike. It wasn't until I topped off the radiator with about a half-gallon of coolant that seems to have raised the level of fluid in the radiator to the leak as well as increasing the pressure in the system to enhance the leak.

In all honesty, I don't know for a fact that the radiator is leaking. It could be a hose or fitting behind the radiator that's leaking, and the coolant then either spews out onto or drips through the radiator, and that's what I see dripping down behind the mesh screens on the chin spoiler and radiator trim panel. Either way, the radiator will have to come off to address the problem and I'm hesitant to tear apart my cooling system considering my limited shop skills and the facts that I have a day job and a two year old competing for my time and attention.

Regardless, this has been an educational and enjoyable experience. It won't be enjoyable when I'm writing the check to my wrench, but the results will be worthwhile.

Final final wrap up is that the bike goes to her wrench on Wednesday for a new (used) radiator. Estimate is $200, parts and labor.

If I knew my wrench was going to ask $200 for a new (used) radiator installed, I would have stopped stressing out about this a long time ago!

England motors

godzilla said:

I used that crap in my pickup truck one time for a pin hole leak. It didn't fix the leak and the truck started running hot. A mechanic buddy of mine told me that the Stop Leak may plug the hole, it may not, but it may also plug the radiator itself. He siad that he wouldn't use it. Ended up replacing the radiator.

Maybe take the radiator to a a radiator repair shop to see if they can fix the leak. I've done that with old cars in the past with good results. if that works on a bike.

You might try looking for a radiator off a wrecked bike or one that's being parted out. I found a good, used instrument cluster that way. See http://www.engelandmoto.com/index.html

Seemed like a nice enough guy and he'e an MOA memeber.

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Phil who owns Engalnd motors is a great source of K parts and many more as well.


Also a local ral shop ccan do wonders with a small or major leak source ot one in your yellow pages you will be surprized how cheap it will cost

98lee said:

I didn't realize there was enough slack in the fuel hoses. Usually when I go in there I'm going for something in the wiring which has required that the tank be fully removed and, while I'm in there, I always check the radiator level. I'll have to give that a try this weekend. Although I imagine you still have to disconect the electrical connection to the tank and the vent hoses and, if not totally remove the seat, at least unclip the stop arm from the seat to fold it out of the way of the tank. But if that works it definitely saves doing the worst part of the job: breaking the fuel lines. Thanks for the tip. The stuff you can pick up on this forum is definitely worth the price of addmission to MOA.

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I think I saw you and your sweetie on Lucas Valley Road a couple weeks ago?

KBasa said:

I think I saw you and your sweetie on Lucas Valley Road a couple weeks ago?

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KBasa,

Sweetie?? Are you talking about my bike or my wife?

That was us. Me on Mine, Her on Hers. We were on our way to Point Reyes lighthouse. Was that you that went by when I was on the shoulder tightening my mirrors?

I had just put a pair of factory hand guards on mine to block the cold air on the back of the hands. But I discovered on that ride that my aftermarket mirrors will pivot on the slippery plastic of the hand guards unless they are really tight. It was no fun trying to hold my left mirror with my thumb all the way across the San Rafael bridge!

But, now that the warm weather is here the hand guards are off. They just mount to the mirror stalk.

By the way if any of you cold weather ( read Northern or Eastern) riders want factory hand protectors for your K75s, they are BMW part#71602315870 $25.00 a pair from Chicagobmw.com.

Final final report

I'm just back from visiting my bike at the shop. Here's what happened:

The shaft of my radiator fan had enough play (~1/8") that it dug into the back of the radiator, causing the hole. It's also likely that the fan would occassionaly "engage" the fins on the radiator, stopping the fan from spinning. This explains a couple of issues I've been experiencing, so I'm glad this situation was discovered and fixed.

$200 installed for a new (used) radiator
$50 installed for a new (used) radiator fan
$50 to replace the tranny fluid, final drive fluid and brake fluid (not related to my cooling system issues, but why not, since it's been three years since these were last renewed by the prior owner?)

dvandkq said:

I'm just back from visiting my bike at the shop. Here's what happened:

The shaft of my radiator fan had enough play (~1/8") that it dug into the back of the radiator, causing the hole. It's also likely that the fan would occassionaly "engage" the fins on the radiator, stopping the fan from spinning. This explains a couple of issues I've been experiencing, so I'm glad this situation was discovered and fixed.

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Wow. I've only heard about this a few times over the years.

I wouldn't have believed it unless I'd seen it myself.

My mechanic said it was obvious the radiator and fan were original equipment, so this problem could very well have been 16 years in the making.

I'm so glad I took this to my wrench, because if I had done the job myself, I would have only ordered a new radiator ahead of time. When I pulled the radiator and discovered the true problem, I would have had to order a new fan, further delaying repairs.

I've certainly never heard of this phenomenon before, and based upon the reactions of my wrench and his assistant, they hadn't seen this before, either. Hopefully that means it won't happen again for at least another 16 years!