Overheating, empty radiator

kjetil4455

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Dear friends,

Went for a ride in the jungle with a friend of mine who has a GS1200. Unfortunately, well, for me, it was my bike who broke down and not the GS as the yamaha groups commonly laugh about.

In the morning I noticed a strange smell, and fumes coming out from the right side of the bike adjacent to the throttle body. Kept on going, figured it was "probably nothing", haha. Bike's temp was normal and the coolant reserve was ful, so I didn't think it was the coolant. Every time we stopped it seemed to get worse, and it smelled more in an incline and less in a decline. The smell then... stopped. It seemed ok. About three hours later, deep into the jungle, the bike started overheating. It had been running virtually nonstop at 105C (I think that's 221F, the max. "normal" temp) for at least one hour, if not two. Now, it was running at 106, 107C, and didn't even come down during downhill riding without giving throttle. I became concerned.

Stopped to check the reserve and it was now EMPTY. I filled it with water and the engine came down to 95C ish, much cooler. We stopped after 20 minutes, and the coolant tank was half empty again. Refilled. AFter 20 more minutes we stopped to check again, and when I stopped, the fluid in the reserve tank was literally boiling, and spilled out of the reserve tank. This happened several more times. I was able to scrape by and get home after 4 hours, overheating lamp turning on just once during an incline which forced me to stop. Cooling system started working again when we stopped climbing upwards.

Sorry for a lot of text. I got it to the stop and we found the radiator empty, so figured it was the thermostat. There was no evident leak through any of the hoses or the rad itself. Changed the theramostat, but it still kept spilling fluids back to the reserve tank and on the floor. Figured it was the lid, so we cleaned the radiator and changed the radiator lid. Seemed to resolve the overheating and it has not spilled fluid afterwards. Now, finally, to my question: After all of this, obviously, I am nerviously following the engine temp. I live in south america, and we have daily temps of at least 35C here. The bike was frequently going up to 106 C which is 1C above spec. It quickly came down as the fan came on, however. I can't recall that the engine reached 106C when waiting in queues before, though.

Any reason to worry?

Apologies for this [perhaps unnecessarily] long back story.
 

Sierra1

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So, are you for sure it was the cap? That much fluid leaking out should leave a trail and be easy to see where it was coming from. If you have the leak fixed, just put the correct ratio of coolant/water back into the specified amount.

Hard to tell at this point if there's any permanent damage or not. I would lean towards not. I know guys that have ran their cars low on fluid and not damaged anything. Watch the temp, that will tell the story.
 

kjetil4455

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So, are you for sure it was the cap? That much fluid leaking out should leave a trail and be easy to see where it was coming from. If you have the leak fixed, just put the correct ratio of coolant/water back into the specified amount.

Hard to tell at this point if there's any permanent damage or not. I would lean towards not. I know guys that have ran their cars low on fluid and not damaged anything. Watch the temp, that will tell the story.
Thanks for your reply!

There was no leak. What happened, presumably, was buildup of pressure in the radiator / coolant system that caused the fluid to force back to the tank and leak out of the tank (the reserve tank). When we changed the cap, this stopped happening.

Permanent damage: Where, if so? It only overheated for like 1 minute total (ie. lamp turned on). The rest of the time, I was around 100 and 105C.
 

Bill_C

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As long as there isn't any coolant in your oil then I suspect that your assumption is correct.
You mentioned a smell from the right side. Your water pump is down there and there is a hose that runs up to the thermostat housing. You may check that for leaks and cracks.
I'd start with the basics of coolant and new radiator cap. Look for obvious leaks at the pump, thermostat and the hose that connects them.

Sent from my SM-S906U using Tapatalk
 

SkunkWorks

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There is also a small "Weep Hose" that runs down the right side of the engine, to the bottom.
It connects to a small chamber where the shaft that drives the water-pump comes out of the engine case.
Make sure there is no coolant weeping out of that small hose. If it is, then the back side of the water-pump is leaking
This hose would weep oil if the shaft-seal at the engine was leaking also.
 

Checkswrecks

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On my first Tenere, there were a couple of times I'd get home from commuting, smell coolant, find the bottle empty, and each time the cap was loose.

Replaced the thermostat, filled the radiator and bottle per the book, and never had the problem repeat.
 

Squibb

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There has to be a reason, but I struggle with the idea this is just the rad cap/thermostat. I've never been that fortunate.

In my experience high coolant temperatures, blowing all the coolant, is usually either the coolant pump failing (blade particles sometimes show up during a rad flush) , the head gasket failing, allowing the coolant system to be pressurised, or a leak, usually the rad itself.

So let's hope you are lucky. Best get an auto shop to pressure test the system though - it's amazing how small leaks manage to hide. We have seen several Super 10 owners with this issue after dropping the bike on the left side, where the fan jabs into the rad fins.
 

Jlq1969

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The idea of the circuit is that it is "pressurized", that will make the water take more degrees to boil than non-pressurized water. If the cap fails, there will be no pressure in the circuit, so the fact that it does not boil will depend only on the refrigerant. If the cap is damaged, "it will not be able to absorb" the water from the reservoir either, because a vacuum will not be generated when the circuit cools and the water contracts. Another point to see is if there is dirt in the cooler (insects or others)... that will reduce the ability to exchange heat
And if the circuit emptied, for it to work correctly again, after filling it up again and doing a couple of temperature cycles... when cold, you have to uncap the radiator and make sure that the liquid is at the level of the cap... like this when hot, it will expand into the reservoir and when it cools, it will absorb from the reservoir….if the cooler is not completely full, the liquid will expand and contract within the radiator itself…..and not in the reservoir…giving you the erroneous sensation of a “false full” (if you only trust the level of the reservoir)….if all is well…the reservoir should increase when hot and then come back when cold, to the cold mark
 
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kjetil4455

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As long as there isn't any coolant in your oil then I suspect that your assumption is correct.
You mentioned a smell from the right side. Your water pump is down there and there is a hose that runs up to the thermostat housing. You may check that for leaks and cracks.
I'd start with the basics of coolant and new radiator cap. Look for obvious leaks at the pump, thermostat and the hose that connects them.

Sent from my SM-S906U using Tapatalk
Thanks! I would know how to check hte coolant for oil, but how do I check the oil for coolant? There didn't seem to be any leaks whatsoever from the actual radiator or hoses. The problem, as it seems, is that the pressure buils up in the radiator forcing the fluid to retrograde to the reserve tank and overfill.


There has to be a reason, but I struggle with the idea this is just the rad cap/thermostat. I've never been that fortunate.

In my experience high coolant temperatures, blowing all the coolant, is usually either the coolant pump failing (blade particles sometimes show up during a rad flush) , the head gasket failing, allowing the coolant system to be pressurised, or a leak, usually the rad itself.

So let's hope you are lucky. Best get an auto shop to pressure test the system though - it's amazing how small leaks manage to hide. We have seen several Super 10 owners with this issue after dropping the bike on the left side, where the fan jabs into the rad fins.
The thing is that the previous owner didn't take care of the bike so well. He did the minimum, ie. oil changes and tyre changes. But that's about it. There were bad steering bears making the bike turn leftwards when using it, for example, that I had to fix. My point being that maybe he neglected the coolant changes and maybe this damaged the cap and thermostat? We took the stat out and it kept retrograding. Then we switched the lid and it stopped happening.

Re dropping: The bike has good crash bars. Pretty sure this is not the problem.

Now, here's another detail... I never had this problem before. When I bought it at 39k Km I changed the oil and filter. All good. Did the oil and filter change again at yamaha recently, literally about a week before the radiator problem started. Could they have overfilled the oil at yamaha causing raised pressures? EIther way, though, that should just be let out by the cap, and as far as I could see, there was no oil in the coolant liquid.

How do I proceed, then? Do I just send it in for a valve inspection (although it's rarely a problem pre 100k Km, I've been told) and just do the head gasket simultaneously?
I guess it could be the water pump as well.

The idea of the circuit is that it is "pressurized", that will make the water take more degrees to boil than non-pressurized water. If the cap fails, there will be no pressure in the circuit, so the fact that it does not boil will depend only on the refrigerant. If the cap is damaged, "it will not be able to absorb" the water from the reservoir either, because a vacuum will not be generated when the circuit cools and the water contracts. Another point to see is if there is dirt in the cooler (insects or others)... that will reduce the ability to exchange heat
And if the circuit emptied, for it to work correctly again, after filling it up again and doing a couple of temperature cycles... when cold, you have to uncap the radiator and make sure that the liquid is at the level of the cap... like this when hot, it will expand into the reservoir and when it cools, it will absorb from the reservoir….if the cooler is not completely full, the liquid will expand and contract within the radiator itself…..and not in the reservoir…giving you the erroneous sensation of a “false full” (if you only trust the level of the reservoir)….if all is well…the reservoir should increase when hot and then come back when cold, to the cold mark
Interesting. I guess that would would also possibly indicate a head gasket problem then, if we just changed the lid and it still doesn't fill up properly. Yes?
The fluid was indeed dirty. Now, obviously, everything's new.
 
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Squibb

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Sorry, I'm not clear here: -

1. Does the cooling system now fill correctly & hold the coolant level stable, within the max/min parameters in the expansion tank, or is it still blowing?

2. If the system remains unstable, then get it pressure tested for leaks first. There are plenty of videos on YouTube for guidance. No one changes head gaskets for fun, so look at the simple solutions before getting the spanners out.

3. Radiator - has it been removed & reverse flushed to check for debris in the system? Any debris witness means the coolant pump must be checked & the whole system flushed through.

4. Oil quality - usually coolant contamination shows as a foam/slime layer above the oil. This may show in the level sight window or oil filler.

5. A fail at #2 & #4 above would suggest a head gasket problem - given the level of overheating experienced, this may prove the inevitable hard truth, but we are all hoping this has been avoided.

Good luck - Keep us posted.
 

kjetil4455

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Sorry, I'm not clear here: -

1. Does the cooling system now fill correctly & hold the coolant level stable, within the max/min parameters in the expansion tank, or is it still blowing?

2. If the system remains unstable, then get it pressure tested for leaks first. There are plenty of videos on YouTube for guidance. No one changes head gaskets for fun, so look at the simple solutions before getting the spanners out.

3. Radiator - has it been removed & reverse flushed to check for debris in the system? Any debris witness means the coolant pump must be checked & the whole system flushed through.

4. Oil quality - usually coolant contamination shows as a foam/slime layer above the oil. This may show in the level sight window or oil filler.

5. A fail at #2 & #4 above would suggest a head gasket problem - given the level of overheating experienced, this may prove the inevitable hard truth, but we are all hoping this has been avoided.

Good luck - Keep us posted.
1. It's no longer blowing out. And yes, within min and max parameters when cold and hot it seems. I just tested it.

2. Referring to #1. But the temp now seems OK. It does go up to 106C and then the fan brings it down to 98 or 99C when in line. On highway, it is significantly lower. Whether it is pressure tested, I am not sure --> but the problem resolved after changing the radiator cap. Also, there is no leak when the engine is warm and running. By unstable, you mean unstable temp, yes?

3. Yes, full maintenance. If it had debris or not, not sure --> it was sent out for maintenance.

4. Level sight seems normal, oil filler also no evidence of it neither cold nor after use.

5. Good news here is that I can get a valve checkup and head gasket change done for about 100 bucks (Colombia), so not the end of the world. Question: Why would #2 indicate a head gasket leak? Is it because the overall pressure would increase? Wouldn't the radiator cap compensate for that and let it out? Thanks. #4 makes sense.

Thanks so much!
 
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kjetil4455

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Oil window, filler view and cap. Looks OK, right? The oil level sank by 10-15% after warming up the engine in the window, but otherwise all views were the same before and after heating it up.
 

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Bill_C

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I don't think you've got anything to worry about, honestly. I have worked on plenty of cars with blown head gaskets. If you had a blown head gasket you would know. You'd have antifreeze in your oil/oil I'm your coolant. Your oil would look like chocolate milk. Based on everything you've said you've checked (and your pictures) I think you're fine.

Completely unrelated, you should get your valves checked though. Don't skip a service because others haven't needed an adjustment. It's inexpensive peace of mind knowing they were checked.

Sent from my SM-S906U using Tapatalk
 

kjetil4455

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I don't think you've got anything to worry about, honestly. I have worked on plenty of cars with blown head gaskets. If you had a blown head gasket you would know. You'd have antifreeze in your oil/oil I'm your coolant. Your oil would look like chocolate milk. Based on everything you've said you've checked (and your pictures) I think you're fine.

Completely unrelated, you should get your valves checked though. Don't skip a service because others haven't needed an adjustment. It's inexpensive peace of mind knowing they were checked.

Sent from my SM-S906U using Tapatalk
Just went to the shop and they said that they already revised the pump. I wasn't there when they did it as I was busy, but it's a fairly good shop so I hope they did a good job, ie. I hope the pump is good as they say. Glad to hear that you perceive the head gasket as ok! Must've been just a cap failure then and dirty liquid?

Might be that simple, as it seems to work OK downhill and not at all uphill. Just enough help from gravitational angle to help the lid open and rid the radiator of pressure.

Thanks again, all!
 

Squibb

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Just to be sure, can I suggest you have the cooling system pressure tested when you get the valve clearances checked.

The bad rad cap & that dirty coolant scenario is still nagging at me - it may be bad maintenance, but it could be the sign of an emergency roadside repair by the previous owner. Your choice obviously.
 

kjetil4455

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Just to be sure, can I suggest you have the cooling system pressure tested when you get the valve clearances checked.

The bad rad cap & that dirty coolant scenario is still nagging at me - it may be bad maintenance, but it could be the sign of an emergency roadside repair by the previous owner. Your choice obviously.
EDIT: Mechancic just told me that they already did the pressure test on the system and it's good. he also said that here, in this very warm climate, the caps and thermostats tend to fail even though there's no leak. IDK if it's true or not but it makes me more hopefully that this clownery might be over and done with
 
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Jlq1969

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The cap is normally calibrated to open when the pressure exceeds a limit and thus avoid overpressure that could damage the radiator and another element of the cooling circuit (normally between 0.8 and 1.2 kg/cm2)... if there is a compression leak in the head gasket, towards the cooling circuit, the compression of a piston, would greatly exceed the working pressure of the radiator cap, making the cap spring retract and throwing the water out of the engine (into the reservoir and from there to the floor)…..until there is no more water to dump
 

kjetil4455

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The cap is normally calibrated to open when the pressure exceeds a limit and thus avoid overpressure that could damage the radiator and another element of the cooling circuit (normally between 0.8 and 1.2 kg/cm2)... if there is a compression leak in the head gasket, towards the cooling circuit, the compression of a piston, would greatly exceed the working pressure of the radiator cap, making the cap spring retract and throwing the water out of the engine (into the reservoir and from there to the floor)…..until there is no more water to dump
Thank you for the explanation! Head gasket seems OK, thankfully. As I understand, if the lid doesn't open, this will also cause sinister buildup of pressure and retrogradation of fluid into the reserve tank? I saw a lot of fluid blow out of the reserve tank over and over until we changed the cap. As stated earlier, there's no oil in the coolant nor coolant in the oil. IDK if this only happens in late or more aggressive cases of head gasket ruptures or if it also happens in more subtle ruptures?
 

Jlq1969

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Thank you for the explanation! Head gasket seems OK, thankfully. As I understand, if the lid doesn't open, this will also cause sinister buildup of pressure and retrogradation of fluid into the reserve tank? I saw a lot of fluid blow out of the reserve tank over and over until we changed the cap. As stated earlier, there's no oil in the coolant nor coolant in the oil. IDK if this only happens in late or more aggressive cases of head gasket ruptures or if it also happens in more subtle ruptures?
If the cap were "stuck" and did not allow some pressure/water to be released to the reservoir... that overpressure would generate an undue leak through the radiator panel or through some hose/clamp
Sometimes, a small leak (in the head gasket) usually causes overpressure and the radiator cap opens, without the water mixing with the oil... a failed cap (which allows an uncontrolled water leak)... "could lead to confusion ”, that the leak is from the head gasket. To rule this out, you could try warming up the engine "without the cover on"... and with the radiator not so full (so it doesn't overflow when you remove the cover when cold)... while the engine is hot, if you accelerate a little and the water looks to come out or idles.....that could be a sign of a leaking head gasket
 

kjetil4455

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If the cap were "stuck" and did not allow some pressure/water to be released to the reservoir... that overpressure would generate an undue leak through the radiator panel or through some hose/clamp
Sometimes, a small leak (in the head gasket) usually causes overpressure and the radiator cap opens, without the water mixing with the oil... a failed cap (which allows an uncontrolled water leak)... "could lead to confusion ”, that the leak is from the head gasket. To rule this out, you could try warming up the engine "without the cover on"... and with the radiator not so full (so it doesn't overflow when you remove the cover when cold)... while the engine is hot, if you accelerate a little and the water looks to come out or idles.....that could be a sign of a leaking head gasket
Thanks alot. If the problem returns I will definitely look into this. Very practical advice!
 
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