Engine overheating

[noipego]

Hi all, my gt suffers from overheating alot latelly ('12 model).
All 3 times i got cool fluid overflow and last time it even melted the exsaust cover. Weird as everything seems to be ok (fluids,fan,sensors) work ok...we checked the temperature with diagnostic while stretching the bike and temp. reached to 103-104 kelsius every time (iv been told thats in the limits of the bike)
Kymco advertises that they upgraded the coolant system for their new scooters like Downtown 350 and Exciting 400... i guess having Italians design goodlooking scooters is not enough

[CROSSBOLT]

No, that is not it. We have both the Downtown 300i and the People GTi300 and neither overheat while both are 2013, essentially the same as the 2012. Additionally, the DT300i is an exact replacement for one that had over 20000 miles that was stolen and it never overheated. Finally, the majority of posts here deal with problems other than overheating. So, having said all that, how 'bout some more information? How many miles? What do you mean by "stretching " the bike? What exhaust cover are you referring? Stuff like that.

Karl
 

[noipego]

Bike has 43.000 km...stretching the motor, like driving near max speed for some time or driving uphills etc.
I am referring to large plastic cover of the exsaust(tailpipe/silincer).
I experienced overheating 3 times in 4 years of use...and each time  after inspecting the coolant system and electronics everything seemed to be ok...i have seen same issue on a people 200 too.

[CROSSBOLT]

Not quite 27000 miles. The big difference I see is we have not ever "stretched" the motor by riding near max speed for long periods. We do cruise at 60 to 65 miles per hour and I had the DT300i to 80 once for a forgotten reason. We have pulled some really steep hills pulling a 350 pound trailer behind the People. All with no overheating. It sounds like you are riding too hard and probably have from the beginning. I think you need a different kind of a machine which is not a scooter.

Karl

[hypophthalmus]

I've never seen the needle on my people 250 creep past the middle mark on the gauge, even when going full speed for longer trips (never more than a couple hours).

Some things to check that I can think of:
Thermostat
Water pump
Possibility of clogs
Clogged/bent radiator fins
Not too high coolant concentration
Properly burped / no air in cooling system

[noipego]

crossbolt: pulling a 350 pound trailer on uphill is quite a stretch in my opinion, but temp was fine as you mentioned. I forgot to mention that i got all overheatings during summer time with temp around 35-36K (95-97F)

hypophthalmus: yes we checked all these. We always remove airbubbles from the fluid and keep it in the right level...but this time we lowered the proportion of antifreeze in the coolant fluid from 60/40 to 70/30 (water/antifreeze)...at least for the summer period.
One last thing that we haven't checked is the impeller of the pump...maybe the blades have become blunt or damaged and the pump cannot deliver a good fluid flow

[Stig / Major Tom]

My understanding is that coolant works best at 50/50 mixture?
Is it not chemically designed to do work best with water,  both for cold AND hot air temps...at 50/50?
Seems faulse economy to change from recommended formula.
Stig

[pipster326]

I agree with Stig, I wouldn't use anything less than 50/50 mix. I did a coolant flush , a couple of months ago and used Maxima motocycle/atv coolant. A little pricey,but never had an overheating problem. Did you ever try using an additive like Engine Ice?


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[noipego]

The recommended mixture is 60/40 in the manual and thats what iv been following since i bought the bike. Just after my 3rd overheating last week i changed the mixture to 70/30 to experiment and see what happens. Although this week is very hot where i live (under the sun it reaches 45*Kelsius) bike has not overheated yet. In couple weeks we ll have the time to check the impeller of the pump and see if theres any damage inside.

@pipster: No i haven't used Engine Ice...but looks like quality product so ill try that asap..thx for advice

[Ossie Carter]

I live in Western Australia just south of Perth.  The summer temp is around 32c during late December to end of March.  Some days during this period get to 45c and I don't have any trouble with over heating.  Oh I have a kymco 500i.  I don't think I have heard the fan kick in either......


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[hypophthalmus]

The 70% water should help for reducing the engine temperature at least since water has a higher heat capacity than antifreeze. 

I think antifreeze has the best freeze/boil performance at 70% antifreeze. But the best heat capacity/lowest temperatures at 30% antifreeze, which I think is the minimum you can get away with while still having adequate corrosion protection. So 50/50 is typically a good balance in most climates.

Apparently the engine ice has propylene glycol which has a slightly higher heat capacity than ethylene glycol. And it seems to be 60% water. Which is probably the basis for its claims. You might be able to find a much cheaper propylene glycol antifreeze as well, just make sure to dilute it to 60% water to get the same performance.

[TLRam1]

Nope, 50/50 is not best, that comes from the mfg who sells the stuff, 70/30 will work better for heat dissipation. 100% water would even work better but needs antifreeze to raise the boiling point to prevent boil-overs. I use what is needed for the cold temps in my area and no more, that would be 60 or 70 percent water.

[Stig / Major Tom]

I used Honda coolant in my Forza;  Suzuki coolant in my Burgman ; go faster in my air cooled LIKE200I.
Takes the guesswork out of the situation.
For 45 yrs read/heard that is critical to use 50/50. This forum is the very first deviation to that recommendation I've ever come across. 
Stig

[CROSSBOLT]

Oh, boy! I think I'm seeing one of those "octane arguments" HEATING up here!

Karl

PS: There seems to be some valid input especially from Ossie in Australia where he's smokin" down the road and it's really hot and he's showing normal coolant temp. And 50/50 like Stig says been here a while, works good, lasts a long time. So Noipego, I now think you may have a problem.

[wheels]

I run my Downtown fast on the Interstates and highways, usually 5+mph over the limit.  Riding in a group I push it WOT to keep up with motorcycles.  Only time the fan has come on is in city riding at 90+F after I have stopped the engine.

I have heard of amateur/pro racers using an 'ice' coolant product that does reduce overheating.

I assume the OP uses distilled water and synthetic oil.  If the 'ice' doesn't fix it, I would cut some plastic to get the hot air 'out' from under the scooter.  My old burgman 400 melted the end cap on the muffler. 

Sound like 'too hot', 'too fast'