ST1300 - Overheating 4 - 5 bars, no leaks

[Igofar]

You guys are awesome! I have never had a drip anywhere I have ever parked, but taking your advice I have removed all tuperware and found a very faint dry green trail from the little water pump check hole. The overflow tank was dry, but the radiator was full. So Monday we will be ordering all the parts to replace the water pump. Looking at the service manual and the hydraulic press and other special tools needed, I guess I'll have to have the dealer change the water pump and thermostat at the same time. I wonder if I can save some money since all the tupperware is off and have them do a valve check/adjustment at the same time?

Is there anyone in Arizona that could help me do this myself; rather than going to the dealer?

Thank you again for all of your help. When the dealer did the radiator flush and refill they should have noticed the leak and told me at that time. Another dealer disappointment.

ST-Owners are awesome. I can't thank each and every one of you enough.

Before you go running off and buying a water pump....is the green stain coming out of the SQUARE hole or the ROUND hole? Big Difference!
Alot of times when you have a coolant leak, the water drains down from the Vee and exits the square hole, as it should, but sometimes the wind blows the exiting coolant
backwards onto the round hold giving the appearance that its leaking from there.
I'd take some simple green or windex and clean the area as best you can, then start the bike and bring it up to 3 bars and turn it off, then watch where the
leak comes from. I've also used arisol foot spray (white powder) to locate leaks by cleaning, spraying, then watching the leak appear before your eyes.
Anything leaking out the square hole indicates loose clamps up in the Vee area (VERY COMMON).
The service manuals are misleading as far as the round hole. Prior to 07 they clearly state if ANY thing leaks out the round hole, replace the waterpump and mechanical seal etc.
However, 07 and newer, Honda fabricated a threaded fitting onto the round hole and runs a OVERFLOW VENT TUBE down under the cowling, and states that a SLIGHT WEEPING
from this hose is normal. Some folks think this was done because Honda was replacing several waterpumps when customers complained about coolant leaks.
This was their fix.
I've got a new water pump, seal, gaskets and everything needed sitting in my tool box, because I believed the servcie manual the first time I found my leak.
After replacing the clamps, I found I didn't need the $250 dollar water pump :nuts1:
Just somthing to keep in mind.
I've not worked on ONE of these bikes yet, that didn't have a coolant leak, up to and including 09's and newer.
YMMV

 

[STPaulK]

... it was amazing the grime and bugs that came out.

There lies the reason I can't buy the "paint overspray" as a reason for a stuck thermostat as others have insisted. The cooling system is not a sealed environment and becomes naturally contaminated over time.

 

[Tom Mac 04a]

There lies the reason I can't buy the "paint overspray" as a reason for a stuck thermostat as others have insisted. The cooling system is not a sealed environment and becomes naturally contaminated over time.

unless you were joking... he meant from the external fins of the radiator, gunk that clogs same..... NOT inside as the system is a closed system. I thought it was more that the additives broke down/wear out.

 

[STPaulK]

unless you were joking... he meant from the external fins of the radiator, gunk that clogs same..... NOT inside as the system is a closed system. I thought it was more that the additives broke down/wear out.

No, wasn't joking, just wasn't comprehending. You are correct, I read it wrong.

I wouldn't call the cooling system sealed, when it has a reservoir vented to the atmosphere. It might be sealed during normal operation but once that radiator spring is overcome by pressure, there is an exchange of fluid to that bottle.

 

[STPaulK]

However, 07 and newer, Honda fabricated a threaded fitting onto the round hole and runs a OVERFLOW VENT TUBE down under the cowling, and states that a SLIGHT WEEPING
from this hose is normal.

I think they started that threaded hose fitting in 08. My 07 does not have it. Thinking of figuring out if I could put one on.

 

[Mellow]

I think they started that threaded hose fitting in 08. My 07 does not have it. Thinking of figuring out if I could put one on.

That's correct - started in '08

 

[STPaulK]

LOL, so that must be the "little weep is OK"?

 

[Mellow]

LOL, so that must be the "little weep is OK"?

I suppose so.. I've never had any one the floor from that location. Did have some on the upper front of the engine from loose hose clamps but have been good since I tightened those.

 

[Justytroll]

My 07 has the hose so it must have started mid year or when they ran out of the old engines without the threaded hole. Igofar's doesn't have it... mine does. Both bikes are 07.

 

[Beedlebugs]

Thank you everyone for your support and suggestions. Overheating has been resolved. We replaced the thermostat and the radiator cap today and while in the process we found the small hose coming out of the side of the radiator tank, just beneath the radiator cap has a plastic T in the hose about 6 inches from the radiator, I believe one line goes to the coolant reservoir and the other, I was told may go up to the heads of the bike. The plastic T was broken where the line splits off to the heads. We immediately went on a hard 180 mile ride up 6% grades on the highway from Phoenix to just south of Flagstaff air temperatures were from 80 to 68 (upper elevations). We were unable to get the engine thermostat to even flash a 4th bar. Also drove in stop and go construction traffic and let it idle for 15 minutes, never to get a 4th bar. The fans cycled on and off like clockwork. I believe the overheating has been resolved. Probable cause was most likely only the plastic T but the Thermostat and radiator cap were replaced at the same time. I want to thank all of you for your suggestions, time, experience, and help. You guys never let anyone down. ST-OWNERS ROCK!!!

 

[Scooter]

Overheating has been resolved. We replaced the thermostat and the radiator cap today and while in the process we found the small hose coming out of the side of the radiator tank, just beneath the radiator cap has a plastic T in the hose about 6 inches from the radiator, I believe one line goes to the coolant reservoir and the other, I was told may go up to the heads of the bike. The plastic T was broken where the line splits off to the heads.

Interesting. One of the lines from that T-fitting goes to the SE Thermal valve under the throttle bodies and the other one does indeed go back into the engine head. If this fitting was broken I would have thought that you would have coolant spraying all over the place. I'm wondering if the radiator cap wasn't sealing properly??? Ah well, glad you got your problem resolved just in time before the toasty weather begins down there.

As a side note, it took me two years to finally find where my small coolant leak was coming from. Turned out to be a small pinhole leak in that same hose that runs to the SE Thermal valve...

 

[STPaulK]

As a side note, it took me two years to finally find where my small coolant leak was coming from. Turned out to be a small pinhole leak in that same hose that runs to the SE Thermal valve...

Yeah, my Dr. assures me that some of that is normal as we age. :

 

[Blrfl]

... in the process we found the small hose coming out of the side of the radiator tank, just beneath the radiator cap has a plastic T in the hose about 6 inches from the radiator, I believe one line goes to the coolant reservoir and the other, I was told may go up to the heads of the bike.

They both go there, connecting to a secondary fitting on the outlets at the top of the engine. One hose makes a detour through the thermal valve, both meet up at the tee and the joined line dumps hot coolant into the radiator.

--Mark