Cooling system efficiency

Remontoire · Aug 20, 2014

At what air temperature, in stop and go traffic, does your cooling system fail to keep up with the heat?

This spring I changed out hoses, o-rings, thermostat, rad cap, elbows and coolant. I was expecting to see more efficiency in the cooling capacity, but did not. In hot summer weather the gauge keeps climbing. It hasn't blown the cap yet, but I don't do much city driving. I am curious how close I am to needing a water pump.

The bike has 165,000km on it and is a 1998. Last year I replaced the timing belt and there were no signs of water pump leaks then and from what I can see, there aren't any now.

When I was into it this spring, the system looked very clean. I have not done a detailed straightening of rad fins.

The fan kicks in normally.

Ideas?

Ian.

c130flteng · Aug 20, 2014

I live in the southern AZ desert and have not had any problems (city or hwy) with cooling issues. I hate to say it but, if everything else looks good I think you are looking at a water pump failure. Even without any leakage, there have been some members who have posted pictures of their water pumps that literally had no fins left. have you checked your radiator for any blockage? It sounds like you have a circulation issue and if there is no blockage in your radiator then I would be looking at the pump.

dwalby · Aug 20, 2014

I posted pics of my finless WP, were there actually others too?

Even my finless pump managed to work more or less normally during SoCal summers with some high-90s days. The needle would get a little high now and then, but once the bike was moving it would always come back down again. The only unusual thing that started happening was the fan sometimes wouldn't kick in, but tested out OK, and the rad was full. My theory on that is the pump didn't flow enough at idle to keep the coolant flowing through the entire system. So the coolant at the fan switch wasn't hot enough to trip the switch, while the coolant inside the engine and t-stat (where the temp sensor is) was getting gradually hotter and moving the gauge upwards. Once I'd get underway again and the engine revs increased, then the pump was adequate for the job, but probably just barely. Another symptom was the fan seemed to kick on later (higher gauge reading) than before, and didn't pull the gauge back down very much.

When I replaced the pump it all went back to normal and the gauge stays in the very low end most of the time now. During longer stops in hot weather the fan kicks on every time at just barely past 1/2, and pulls the needle back to just below 1/2, (just like Brant said it should)

pbagley · Aug 20, 2014

In stop and go traffic this summer my 2001 will climb to just past 12:00 on the gauge, the fan kicks on, and the needle never gets past 1:00 or so.

How warm does the engine get when running at highway speed? My the temp needle on my 2001 gets to about 10:30, or half way between the start of normal and straight up.

Have you checked for bugs and mud in the radiator? Is the fan motor getting tired and not running at full speed? Are you running Honda branded coolant? Have you tried "Water Wetter"?

Remontoire · Aug 20, 2014

Thanks guys. Looks like a water pump is in order, like I hunched It's fine for cooling in most circumstances, but the pump is showing its age. Thanks again for the prompt replies. I'll be trying to ride the year out with it as is. What we call heat here in the great white north is drawing to a close anyway.

Cheers. Ian

dwalby · Aug 20, 2014

I've got a used one I'll sell ya

Brant · Aug 20, 2014

dwalby said:
I posted pics of my finless WP, were there actually others too?

Even my finless pump managed to work more or less normally during SoCal summers with some high-90s days. The needle would get a little high now and then, but once the bike was moving it would always come back down again. The only unusual thing that started happening was the fan sometimes wouldn't kick in, but tested out OK, and the rad was full. My theory on that is the pump didn't flow enough at idle to keep the coolant flowing through the entire system. So the coolant at the fan switch wasn't hot enough to trip the switch, while the coolant inside the engine and t-stat (where the temp sensor is) was getting gradually hotter and moving the gauge upwards. Once I'd get underway again and the engine revs increased, then the pump was adequate for the job, but probably just barely. Another symptom was the fan seemed to kick on later (higher gauge reading) than before, and didn't pull the gauge back down very much.

When I replaced the pump it all went back to normal and the gauge stays in the very low end most of the time now. During longer stops in hot weather the fan kicks on every time at just barely past 1/2, and pulls the needle back to just below 1/2, (just like Brant said it should)

Lol.........U just like pickin' on me whenever the opportunity arises

.

Remontoire · Aug 20, 2014

dwalby said:
I've got a used one I'll sell ya

Is this one of those situations where the appropriate response might be "I was born at night, but not in the dark?"

dwalby · Aug 20, 2014

Brant said:
Lol.........U just like pickin' on me whenever the opportunity arises .

quite the opposite, giving credit where credit is due. I apologized when the facts revealed that your claims were correct, and my slowly aging water pump had been leading me to believe that 3/4 range was where the fan kicked on. When I realize I've made a mistake I'm the first to admit it.

edit: when may be the operative word here, if I'm not smart enough to realize I've made a mistake then that's a different story.

dwalby · Aug 20, 2014

Remontoire said:
Is this one of those situations where the appropriate response might be "I was born at night, but not in the dark?"

Its a high-performance model, the fins have been modified for both less weight/lower drag so it requires less inertia to turn.

Brant · Aug 20, 2014

dwalby said:
quite the opposite, giving credit where credit is due. I apologized when the facts revealed that your claims were correct, and my slowly aging water pump had been leading me to believe that 3/4 range was where the fan kicked on. When I realize I've made a mistake I'm the first to admit it.

edit: when may be the operative word here, if I'm not smart enough to realize I've made a mistake then that's a different story.

Well, I also learned something from you also........had seen pump impellers in the automotive world look like the cond. Yours was(great pics BTW), but just never transferred that diagnoses that led you to the water pump as the culprit. For future reference, I'll remember NOT to leave that possibility out of equation. Nice work! Thanks goes to you sir!

.

Remontoire · Aug 21, 2014

dwalby said:
Its a high-performance model, the fins have been modified for both less weight/lower drag so it requires less inertia to turn.

You could sell Christmas cards in June.

Brant · Aug 21, 2014

.....and you missed the mailing list?

ST1100Y · Aug 23, 2014

dwalby said:
Its a high-performance model, the fins have been modified for both less weight/lower drag so it requires less inertia to turn.

LOL! :lol:

The more scientific question though: what is causing such erosive corrosion? Has tap-water been used? Are particular coolants prone to cause it?
IIRC is the impeller made of stainless steel, so what's eating it away to that degree?
I suspect galvanic corrosion due material mix with just the *wrong* liquid present...

Brant · Aug 23, 2014

ST1100Y said:
LOL! :lol:

The more scientific question though: what is causing such erosive corrosion? Has tap-water been used? Are particular coolants prone to cause it?
IIRC is the impeller made of stainless steel, so what's eating it away to that degree?
I suspect galvanic corrosion due material mix with just the *wrong* liquid present...

Throw a tad of outside air in the mix, and that a EXACTLY what you have

.

dwalby · Aug 23, 2014

ST1100Y said:
The more scientific question though: what is causing such erosive corrosion?

Not much of a mystery there. I did use the official Honda coolant, since 15 years ago I bought a gallon and you mix it with water, so that gallon will last a long time. Can't recall if I used tap water or distilled, as I've used both in the past.

One day I looked at the bike sitting there in the garage, and thought holy crap, when was the last time I flushed the coolant? I had totally forgotten about it. It was probably 8-10 years, as I still had my 15 year old jug of the Honda coolant sitting on the shelf, that's how often it had been changed. What drained out was a putrid orangey mess.

Bush · Aug 25, 2014

dwalby said:
Not much of a mystery there. I did use the official Honda coolant, since 15 years ago I bought a gallon and you mix it with water, so that gallon will last a long time. Can't recall if I used tap water or distilled, as I've used both in the past.

One day I looked at the bike sitting there in the garage, and thought holy crap, when was the last time I flushed the coolant? I had totally forgotten about it. It was probably 8-10 years, as I still had my 15 year old jug of the Honda coolant sitting on the shelf, that's how often it had been changed. What drained out was a putrid orangey mess.

Of course, since those 15 years have passed, Honda now offers Type 2, premixed.