ST1300 - Overheating 4 - 5 bars, no leaks

Beedlebugs

Beedlebugs

Joined
Sep 23, 2009
Messages
44
Location
Anthem, Arizona
Bike
ST1300
Please Help, I have 75,000 miles on my 03, no leaks of any kind. Noticed in heavy traffic last summer in Phoenix, temperature around 115 in heavy stop and go traffic, that the gauge hit 4 and 5 bars, then when I got on the highway at 55 it slowly came down to 3 bars. I had the coolant flushed and refilled at the dealer, hoping to fix the problem. Still have the overheating problem and no leaks. When I run at 75 mph or higher even when the outside temperature is 60 degrees it will still hit 4 bars and when I pull off the freeway to surface streets the gauge will go up to 5 bars for a while, then down to 4 bars. When I get to my garage the fan is running and pulling air through the radiator, the fan kicks on and off like it should.

I have purchased another Thermostat, but would like to see if anyone else has had this experience and found a solution, maybe a bad water pump that is not leaking, etc. This is my daily commuting vehicle 85 - 100 miles everyday, 365 days a year. I can't afford to be without it, or cause damage by continuing to drive it this way.

Please help...

Thank you,

Beedlebugs
 
Time for a radiator flush/change? You may also want to confirm your fans are working.
 
Thank you for the reply and suggestions. I had the dealer complete a radiator/coolant flush and refill; and we both confirmed the fans are cycling on and off correctly. I even made sure the fans were pulling air through the radiator the right direction. I know someone else had an overheating problem on an older bike and we eventually figured out the fan was plugged in backwards and was pushing air the wrong way. fixed the plug and the overheating stopped.

Thank you again for the reply and suggestions.

Beedlebugs
 
Sometimes, the air temp is just too darn hot and the fans can't keep up. It's still 'operating within' the guidelines per Honda. Thermostats typically fail open which would only cool your bike off more, they rarely fail closed and if it did in those temps you'd probably have a heap of melted metal... lol.. just kidding.

Good idea to flush the system if it hasn't been done before or in a long time, that may fix the issue.
 
I was thinking fans, but that's been checked. I had a thermostat stick closed once on a car. That was years and years ago. It overheated big-time. Coolant was bubbling back out the fill spout on the radiator. Rare, but it does happen. I like the suggestion of the wrong coolant mix. But it would probably have to be straight, undiluted coolant, or something close to it. Something real thick that isn't flowing properly.

But my best guess is a plugged radiator core. I haven't heard of that on an ST, but I have heard of the factory leaving junk in the coolant system. Maybe you got an extra dose of 'junk'. The best way to clear that would be to back-flush the radiator. I'm thinking one of the flush kits for your car that you hook a garden hose up to. It's be interesting to figure out a way to hook it up to your radiator, but if you could plumb it up to the radiator outlet, the water would be forced backwards towards the top and hopefully push out anything plugging the core channels. I don't know how the dealer flushed your system, but my guess would be that they drained and filled it a couple of times and called that a flush. That wouldn't help if you had particles in the radiator big enough to plug it up.
 
The fans only come into play when a bike is stationary or moving too slow to force air through the radiator. If it hits four bars at highway speeds the problem is not the fans but rather the inability to carry engine heat away through the process of moving coolant through the radiator. If it does not overheat at idle or low speeds the sustem is working well enough to carry off heat the engine makes at those low power settings. I agree the problem is a clogged radiator or coolant passage. The water pump should not be suspect if it is not leaking. Although the thermostats usually fail open on the 1300 it could fail partially closed. In my experience with other types of t-stat a temporary cure for overheating was to remove the t-stat to see if the engine could move enough coolant to stay in the normal range.
 
It's alway a good idea to go with the simplest/cheapest fixes first then move on to the next...

So, in this case I'd;
1) remove radiator and A) clean the fins, more than 10% clogged will make a big diff, straighten any bent. B) clean the insides with a little bit of vinegar/flush kit
2) change out the stat just in case .. its only a $20 item ( remember new o-ring )
3) put back together, add proper mix of antifreeze and fill as manual requires ( remember to burp system by a few quick snaps of trottle after filling )

If all the above doesn't work, its either a fairly well clogged rad or problems with pump... neither of which have a high failure rate.
 
dduelin said:
temporary cure for overheating was to remove the t-stat to see if the engine could move enough coolant to stay in the normal range.
Click to expand...

+1 here. That would be a quick indication of whether your t-stat is bad and lead you to your next step.
 
You say you don't have any leaks. Does this mean theres no coolant leaking on the ground? Leaks don't always reach the ground on these bikes. You need to get down on the left side with a flashlight and look up into the cowling in the area near the round and square holes. You make be surprized to see green trails or an oily like goo all over the side of the engine. This would indicate that yes you do have leaks. You need to check the coolant level (HOT) on the overflow tank as well. No big deal, its usually fixed by simply replacing the cheap oem clamps with better hoseclamps or breeze clamps (search threads). Alot of times when you pay the dealer to service the coolant system, they simply pull off the lower right hose, drain it out, put the hose back on and refill it. This does not FLUSH or clean all the junk and paint that could be in your system from the overspray on the radiator (common). I would follow the advice already given then remove all the tupperware, drain the radiator, take it to your sink and flush it out with HOT water until it runs clean, then while I had it in the sink, I'd take a soft toothbrush and clean all the fins out (bugs & roadgrime). Then I'd check all the hoses for leaks, replace the clamps, remove and replace the oil galley plug (under the t-stat housing) with hondabond, the replace the T-stat & O-ring.
I'd then refill the radiator, and BURP out the air (air in system can cause overheating too). Don't forget to remove and clean your overflow tank (vinegar & simple green & a hand full of BB's and shake). I'd then Do an engine oil & filter change, and replace whatever oil your using with a HDEO (Delo 400LE, Valvoline Premium blue, Mobil Delvac 1300, or Rotella T 15-40wt.) This oil will allow the engine to run cooler than any 10-40 or synthetic. I'd also replace the air cleaner and plugs while I was in there.
Do all this, and I'll bet your bike runs 100% better and the problem will go.
Hope this helps.
Ride safe
 
I would check the radiator cap. It can go bad and make things run hot. I had that happen on a Yamaha Venture. It was about ten years old and according to the mechanic at that age it was likely bad. The bike ran close to the red at freeway speeds at around 85 degrees. A new radiator cap and it was back to normal. H[IMGR][/IMGR]opefully your problem is that simple.
 
Nothing really to add here that hasn't been said, but I think a stuck closed thermostat is unusal, but quite possible. While changing that, thoroughly flush the radiator and clean and straighten fins. Make sure the water flows through the radiator. Make sure you burp the system of air after refilling.

If after that, it's still overheating, it's most likely a water pump. I think the above would take care of it, though. Not a hard job. You do NOT have to take off the tank, airbox and throttle bodies as the manual says to get to the thermostat.
 
thats true, just remove the front cowels and radiator... and since you should be checking out the rad anyway, once off the stat is right behind a frame support bar...easy access.
 
STPaulK said:
Don't discount the possibility of a sensor or sensor connection issue.
Click to expand...

:plus1:

This is my first thought since you already had the coolant changed. How fast does it take to reach four bars? If you have a stuck closed thermostat, and I highly doubt that (I have yet to see anyone post here with that issue confirmed), the bike would be getting super hot especially if you're running it above 100 degrees. Have you tried touching the radiator to see how hot it is getting? Do be carefull doing that or else use an IR thermometer. If the radiator is hot in all spots your thermostat is open and you've got flow throughout.
 
:th1:

Igofar said:
I'd then Do an engine oil & filter change, and replace whatever oil your using with a HDEO (Delo 400LE, Valvoline Premium blue, Mobil Delvac 1300, or Rotella T 15-40wt.) This oil will allow the engine to run cooler than any 10-40 or synthetic.
Click to expand...


:nuts1:

IGF, really now, can you offer some legitimate proof for this?!?
 
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.
 
pretty sure there's a service thread on the site that illustrates very well how to go about doing that. might take a look before heading to the dealer.
 
I recall a few years back flushing out the radiator on a big excavator i was working.the head gasket had blown and oil got into the cooling system making an alfull mess.We used caustic soda.We flushed it a few times and the whole system came up like a new pin.There are also companies who will make a new radiator for you at much lower cost than buying a honda unit.
Pat
 
Much great advice offered already. While it is down for the water pump, take the opportunity to clean the radiator inside and out as mentioned. While mine was down for service recently, I soaked the radiator in a deep sink for a couple of days, occasionally blowing out the fins... it was amazing the grime and bugs that came out. The results was a cooler running machine. Good luck with the repairs.
 
Scooter said:
:th1:




:nuts1:

IGF, really now, can you offer some legitimate proof for this?!?
Click to expand...

Legitimate proof of this.....No. Just based on personal experience in my 2007 Harley Davidson Roadking Classic, Springer Softail Classic, GL1800 Honda goldwing, and my 2007 ST1300, In comparing Mobil 1 4T 10-40wt. Fully synthetic oil, vs.
HDEO's I've used. While not being very scientic, I used a heat temp gun and fould in My four vehicles, that the temps were always lower when I used the HDEO's. Perhaps it was just the Mobil 1. I should have been more specific about the oil in my post.
I compared all the vehicles under the same conditions, Route, speed, distance, tempature. The Delvac 1300 (in Harley's) and the Delo400 or Valvoline Premium blue in Honda's always yielded lower numbers than the Mobil 1. YMMV.
 
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