Coolant reservoir cap.

longerone

Joined
Apr 15, 2010
Messages
112
Location
nigeria
Bike
04 ST1300
lost my coolant reservoir cap, as i frequently need to open the reservoir in order to confirm coolant level(not visible to me by looking at the 2 level marks).I looked for it but couldn?t find it, tried the local auto shops, maybe i could get any cover of the same size but no such luck. so i just used a piece polythene to plug the hole, this i know allows air into the reservoir. As a precaution i check coolant level every ride and find i need to add distilled water to mark it up, I assume this is because the reservoir is not airtight. But on a recent town ride i noticed the coolant pouring out from under the bike, i got worried and checked the reservoir, it is full to the brim, i can not understand why cos i didnt overfill it B4 i rode out.
So now i have 2 problems.
1-To get the right size of cover locally or improvise.
2-How to get the correct coolant mixture ratio, using locally available auto coolants.
Hopping no damage to my cooling system.
Happy and safe riding new year.
 
For #1: Any firm-fitting stopper will work fine. That part of the system isn't airtight.

For #2: If Honda imports automobiles to Nigeria, locate a parts supplier and see if they have Honda Type II coolant. It's the right stuff and is pre-mixed.

Normally, you shouldn't have to be adding coolant. The recovery tank holds expansion from the radiator, and it should get sucked back in as the engine cools. If you've been adding water, the system is probably losing coolant, and eventually the ratio of coolant to water will favor water and you'll start overheating. This might be a good time to check for leaks and do a full change-out.

--Mark
 
As a stop gap measure for the reservoir, cut a stiff piece of plastic (like the top from a margarine container) in a circle equal to the outer diameter of the filler and cover with a balloon.


Sent from my iPhone using Tapatalk
 
echo said:
Hmm my assumption is water is a more effective coolant than coolant (and water). So your cooling efficiency should increase not decrease with more water. Of course, freezing, corrosion and other undesireable things can result.

Or am I wrong about this?
Click to expand...

You are right: A 50/50 ratio of ethylene glycol mixed with water is indeed less efficient at carrying off heat than pure water. Roughly 20% less specific heat, in fact. However there's another consideration: the boiling point of 50% glycol is significantly higher than water alone. 225?F against 212?F for water. Running with water alone is not desirable at all since your water is working at or near its evaporating temperature. Pressurizing the system brings the boiling point even higher, so you are even safer if the cooling system is pressurized.

I say the OP should find correct cap, and use the right mix of ethylene glycol and water. The brand name of the coolant is not that important.

And finding the right cap in the States and having it shipped to Nigeria should not be a problem. The Radiator cap costs about 21$ US, and the reserve tank cap is about 4$.
 
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echo said:
Hmm my assumption is water is a more effective coolant than coolant (and water). So your cooling efficiency should increase not decrease with more water.
Click to expand...

As UZ pointed out, temperatures in the engine run much closer to the point where water will boil vs. a 50/50 mix, and there are almost surely going to be places in the engine that push it across that threshold. Steam doesn't cool like water, and being a gas it displaces liquid from places in the system that need to be cooled. Since the engine is still generating heat at the same rate and has to dispose of it, that puts more load on what liquid is left and will make more steam. Pressure will eventually build to the point where the valve in the radiator cap opens and blows steam and coolant into the recovery tank, which in turn dumps it on the street once it's full. If longerone is having this happen, it's a sign that something's not right in his cooling system, and every time he adds water, the boiling point of his coolant drops closer to 212F, which will only make the problem worse.

The people who built the bike know that the 50/50 mix is less efficient, but since it stays liquid, they can make up the difference by adding efficiencies in other parts of the system like circulating it faster and having a large enough radiator and fans to exchange the heat. As those who've had stuck thermostats know, the entire cooling system is efficient enough on even a cool day to drag the temperature of the engine far below what it should be, and that results in poor performance and fuel economy. Trying to make the coolant more efficient would be one of those things where "perfect" is the enemy of "good enough."

--Mark
 
echo said:
Hmm. I think I heard if you want to run on a track you got to change out the coolant for water. I guess they do that. It must work.
Click to expand...

Well about that part I really don't know, although a quick search on Google leads me to believe that you are right: Formula One engines are cooled with water. But their cooling system is pressurized. At 15 psi, water boils at 250?F, so it should be OK if the thermostat is set under that temperature. On F1 engines, cooling systems must be pressurized like hell, so flashing is not a problem. They take really good care of their engines, flush them after every race, and store them full of stabilizing stuff.That is really different from operating a stock engine designed for longevity and reliability for long periods in Nigeria. But I am just guessing here.

My point was simply that you are correct in saying that water is a better coolant than a water/glycol mixture. But it's also operating closer to or at its boiling point, which is never good. That, I know for a fact. In HVAC heat exchangers, we are always worried about operating close to the boiling point because there can be localized flashing on the jacket surface, and that leads to scaling and loss of heat exchange, or vapor lock so the cooling system stops working, or there can be significant loss of coolant by evaporation, which is never good. And on that we also agree, because using water instead of glycol/water brings all sorts of problems like corrosion, scaling, freezing, and loss of performance.
 
there's enough damaged bikes out there to get a replacement... for temp stretch a balloon over the top ( damm mdog beat me with that one )

And, how about Prestone Extended Life antifreeze if available... it comes premixed, mixes with all types and has the lack of silicates.
 
userzero said:
Well about that part I really don't know, although a quick search on Google leads me to believe that you are right: Formula One engines are cooled with water. But their cooling system is pressurized. At 15 psi, water boils at 250?F, so it should be OK if the thermostat is set under that temperature. On F1 engines, cooling systems must be pressurized like hell, so flashing is not a problem. They take really good care of their engines, flush them after every race, and store them full of stabilizing stuff.That is really different from operating a stock engine designed for longevity and reliability for long periods in Nigeria. But I am just guessing here.

My point was simply that you are correct in saying that water is a better coolant than a water/glycol mixture. But it's also operating closer to or at its boiling point, which is never good. That, I know for a fact. In HVAC heat exchangers, we are always worried about operating close to the boiling point because there can be localized flashing on the jacket surface, and that leads to scaling and loss of heat exchange, or vapor lock so the cooling system stops working, or there can be significant loss of coolant by evaporation, which is never good. And on that we also agree, because using water instead of glycol/water brings all sorts of problems like corrosion, scaling, freezing, and loss of performance.
Click to expand...

Thanks for all your contributions as always . The total amount off distilled water i added over time is less than 1 litre so i guess this shouldnt make the coolant purely water, but i dont know the total capacity of the cooling system. Thanks for the ingenous suggestion of the ballon contraption, however im still curious as to why the reservoir fills to the brim and coolant pours on the street. Im not sure if the coolant is pouring from the reservoir cap or the pipe under the bike, but the coolant colour pouring out is green, suggesting its not as diluted as is bieng discussed. Thanks.
 
echo said:
Hmm. I think I heard if you want to run on a track you got to change out the coolant for water. I guess they do that. It must work.
Click to expand...

My understanding is that antifreeze is not allowed at any track, because of spills. It is extremely slippery when on the tarmack. So, mostly water is used or perhaps some kind of synthetic coolant. To get adequate cooling they will modify the size of their radiators, etc.
 
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