Coolant Leak

[TownsendsFJR1300]

Has anyone checked the tightness of ALL the hose clamps? (any/all the coolant runs thru).

They will loosen over time, allow the smell, and also not let the system hold pressure if really loose...

When the engines hot, and if the leak isn't bad, the leaked coolant can evaporate quickly and make

finding the leak much harder.

Even thou the bike is still fairly new, with the many heat cycles, those hoses WILL loosen up over time...

 

[Bill Lumberg]

Whatever this was caused suddenly during warranty work. But all the connections are part of what we plan to check when we do the exploratory.

 

[rbentnail]

Has anyone checked the tightness of ALL the hose clamps? (any/all the coolant runs thru).
They will loosen over time, allow the smell, and also not let the system hold pressure if really loose...

When the engines hot, and if the leak isn't bad, the leaked coolant can evaporate quickly and make

finding the leak much harder.

Even thou the bike is still fairly new, with the many heat cycles, those hoses WILL loosen up over time...

Good point! I'd forgotten about that. Over time I've replaced all my crappy OEM hose clamps with working normal ones.

 

[mech 1 twa]

I've read most of this. Everything you describe points to bad head gasket. Excessive pressure pushing coolant into overflow tank, combustion pressure.

Internal pressure into cooling system, causes air pockets hot spots as air is mixed in. Head gasket can leak but have no coolant going into oil or cylinders.

Dealer messed something up. Over heated engine, then added some kind of stop leak. Difference in coolant colors you described. I've seen this problem before on a few cars nothing different with a motorcycle engine compared to car.

Replaced my wife's head gasket on her Honda Civic same issues. Her car never over heated caught it early. 25 plus years Honda auto Tech. Just my 2 cents.

 

[TownsendsFJR1300]

A leak down test would confirm this ^^^..

 

[Fred W]

I had considered the head gasket as well (I've had a bad one on one of my Saabs in the past) but the symptoms do not jibe. If it were a head gasket it wouldn't only pressurize or overheat when stationary. It would actually be more likely when being driven down the road and generating max combustion pressures. That is the key difference with Bill's symptom.

I still believe that this is a cooling system capacity issue. The cooling system is not removing enough heat when only the fans are pulling air through the radiator. When he's riding down the road no overheating and the bike temp will regulate normally.

 

[dcarver]

Bill's FJR should meet my Kz1300 and have a wild hot child. Just sayin'.

 

[mech 1 twa]

I still think its the head gasket. Its not a huge amount of pressure escaping but enough to push the radiator cap up.

Leak down may show this but not in a compression loss way. Fill system and remove rad. cap look for bubbles. Won't be a lot

When I check autos I have a tool that fits on rad. fill coolant and you can see bubbles.

Won't get hot while driving coolant is circulating much faster than at idle plus airflow through rad.. I see what you are saying about max combustion pressure at higher speeds but this is such a small leak around cylinder liner, gasket.area.

I've seen this many time on cars, pushes coolant into overflow at idle. Runs ok down the road.Once coolant is not to the top of rad. pressure is just vented into overflow tank. Bubbles.

Coolant will not be pulled back in after cooling down, system is still pressurized from air in system.

 

[Fred W]

Like I said, I too have seen the leaking head gasket phenomenon, and it isn't easy to diagnose unless it leaks coolant or compression into the oil galleys.

I'd be very surprised if that was what this was, on a nearly new engine, especially since we do not have a lot of cases of head gasket failing on FJR engines, but I would never say never. I'd say it's in the remote "could be" category, but rule out the easier stuff first.

I guess one possible test would be to run the engine at idle with the rad cap off and watch (and smell) for exhaust bubbles leaking out.

 

[dcarver]

NAPA sells head leak detection fluid test kit. Works good. Used on KZ1300.

 

[Fred W]

That is for coolant in the oil though, isn't it?

 

[ionbeam]

^^^^ There are test kits for combustion gases in the coolant. BTDT with cars.

 

[mech 1 twa]

I use a small fill funnel that has adapters for different rad. cap types. You fill system , leave some room for expansion. Run engine to purge air and watch for bubbles.

This would be hard to use on FJR due to cap location, could be adapted with a short hose .

Only takes 1 time to warp a head, heat. I've seen temps recorded as high 405f .auto ECU records FREEZE DATA when problem is tripped.

 

[TownsendsFJR1300]

A simple leak down test will show a cylinder (or two) whether it's holding pressure (good head gasket) or not without a doubt.

The cylinder won't hold pressure, bubbles will show up in the radiator, no guessing...And it'll be much lower than the rest..

And you'll know exactly what cylinder is bad, IF ANY..

Eliminate the guessing IMO...

 

[jammess]

My money is on a leaky head gasket and maybe a warped head. I also wonder if, when it was at the dealer for the original problem, they didn't get into the valve train checking for a tight valve then screwed up and got on the wrong bolt.

It's nonsense like this that makes me nervous about ever taking my FJR to a dealer shop. These Yamaha dealers anywhere near me don't know anything about an FJR and the local dealer freely admits it but they told me they would do their best if I needed service. So, I just spent $89 and ordered a FSM to go with my Haines manual.

Woo Hoo...GO CUBS!!

 

[Bill Lumberg]

No coolant being pushed into overflow. No bubbles visible during idling. Being driven daily with no issues most days. Should have time for the flush/fill/look-see sometime over the next two weeks. Radiator is unobstructed. Fans blow just as hard as they did before. Most likely problem is air or pinched hose. Will want to eliminate the most likely cause first. Given 75-85 degree ambient temps, on a bike already at operating temp, where do your gen 3's top out sitting still, before going back down when he fans come on? Before the shop screwed it up, IIRC, mine always topped at about 221F. And that's usually the case now. Only once in a while will it go on up to 230ville. Those are the rare times when I know I have to move or shut it off for a minute. Remember, no overflow or coolant smell since initially picked up from throttle body replacement.

Odds are shop didn't do anything they didn't absolutely have to to get the throttle body swapped. No sync, etc. the wild card was that the coolant overflow bottle had been filled to the top with water, but the shop swore no coolant/lines were in any way involved with the work, and swore they did not add the water to the overflow bottle. Water stayed crystal clear for weeks. Coolant in the radiator still a deep green.

 

[ionbeam]

...the shop swore no coolant/lines were in any way involved with the work...

Does this mean that the Gen III TB rack no longer has a coolant actuated wax motor? I assume that the wax motor went away with the fly-by-wire TB system. Since the wax motor has never been mentioned in any previous FSM the only way to tell for sure is to use an inspection mirror, flashlight and some patience and look -- or hold a removed TB in your hands.

 

[Bill Lumberg]

When I asked about the problem, the mechanic told me that on this particular model, unlike some others, there was no need to remove coolant lines or drain coolant to swap throttle bodies..... personally, I don't know.

 

[Fred W]

No, the wax motor went away in 2013. There is no need for a mechanical device to increase intake air flow during cold idle as the ECU does that through the fly by wire servo, just like it controls idle speed when warm and so there is no more idle speed adjustment..

And no need for a flashlight to confirm this. You can tell by comparing the parts diagrams of the 2012 throttle body to that of the 2013 throttle body assemblies. Although not available separately, the wax motor and linkage is clearly shown on the 2012 (lower right corner) and is conspicuously absent on the 2013 and later.

 

[TomInPA]

Isn't there a simple coolant test for exhaust gases that could help rule out the head gasket issue?