Hello and thx already.... I think it could be a fan/thermo switch but I have no clue. what does the great minds of st owners think? thx :bow1:
1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switch?
- Thread starter Dmays
- Start date
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
Very little info to go on. You are very new here, so are you new to the ST too? Maybe it isn't really overheating, if you are unfamiliar with the way the temp gauge reads?
Very little info to go on. You are very new here, so are you new to the ST too? Maybe it isn't really overheating, if you are unfamiliar with the way the temp gauge reads?
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
I would FIRST suspect low coolant level, and the overflow tank is NOT where that is checked! With bike cool, your gonna have to remove some tupperware(start with the suitcases
) to easily access the rad. cap. Should be full to ing top of neck. If not, fill. Check that overflow hose doesn't have a split in it(common at rad. connection). Look over for any suspicious areas for leaks, top-off overflow to FULL mark, Satisfied?......leave tupperware off(for a visual afterwards) and go ride up to operating temperature.
I suspect a couple areas of leaking without any electrical component being condemmed......yet. .......Oooh, and we ALL like to know what your findings are.
BTW, thermo sensor wont allow fan to come on if coolant low.....it needs to be submerged.
Hot day(90+), 70+mph, temp gauge needle normally sets between half way to halfway(in that makes sense) to '11o'clock''.....at which time fan should come on.
I would FIRST suspect low coolant level, and the overflow tank is NOT where that is checked! With bike cool, your gonna have to remove some tupperware(start with the suitcases
) to easily access the rad. cap. Should be full to ing top of neck. If not, fill. Check that overflow hose doesn't have a split in it(common at rad. connection). Look over for any suspicious areas for leaks, top-off overflow to FULL mark, Satisfied?......leave tupperware off(for a visual afterwards) and go ride up to operating temperature. I suspect a couple areas of leaking without any electrical component being condemmed......yet
. .......Oooh, and we ALL like to know what your findings are.BTW, thermo sensor wont allow fan to come on if coolant low.....it needs to be submerged
.
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Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
To elaborate a bit more on Bush's comments, its normal for the 1100 temp gauge to climb high enough to kick on the fan while stopped in traffic. You need to be traveling 40-45mph or so to get enough airflow through the radiator to keep the needle down in the lower range.
So give us a few more specifics:
1. does the fan come on?
2. if the fan kicks on does the needle drop back to just below 1/2?
I suspect you're not getting the needle to drop back, but to help diagnose your issue you have to provide a bit more information. Brant has also provided the first few steps of diagnosing the problem.
To elaborate a bit more on Bush's comments, its normal for the 1100 temp gauge to climb high enough to kick on the fan while stopped in traffic. You need to be traveling 40-45mph or so to get enough airflow through the radiator to keep the needle down in the lower range.
So give us a few more specifics:
1. does the fan come on?
2. if the fan kicks on does the needle drop back to just below 1/2?
I suspect you're not getting the needle to drop back, but to help diagnose your issue you have to provide a bit more information. Brant has also provided the first few steps of diagnosing the problem.
ST1100Y
Site Supporter
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
Most ST1100 temp gauges needles read [12:10hrs] when the fan kicks in, and [11:50hrs] when it stops again.
Something is off if the needle bounces further up/to the right; often just low coolant level, exposing the temp sensor to "steam" thus high reading on the gauge...
+1 on the speed issue... below ~40mph the fan just won't stop on a hot day...
Most ST1100 temp gauges needles read [12:10hrs] when the fan kicks in, and [11:50hrs] when it stops again.
Something is off if the needle bounces further up/to the right; often just low coolant level, exposing the temp sensor to "steam" thus high reading on the gauge...
OP
OP
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
thx... I'am new to the ST world. The coolant level is full in the reservoir and the tempture goes to 1:00 easy. Till I start moving again... as long as Im not city driving Im ok. NO leaks(not a drop) and I've only heard the fan kick on twice. WAY past the 1:00 position. thx again..
thx... I'am new to the ST world. The coolant level is full in the reservoir and the tempture goes to 1:00 easy. Till I start moving again... as long as Im not city driving Im ok. NO leaks(not a drop) and I've only heard the fan kick on twice. WAY past the 1:00 position. thx again..
OP
OP
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
Hello Brant.. res. tank in full. no leaks(I can see or smell) and the fan has only came on twice(very high temp). runs great when not in the city.... Your telling me to check res. tank right? The radiator cap is under insturment cluster right? I can not get to that.... thx again.. you folks are AWESOME!!
Hello Brant.. res. tank in full. no leaks(I can see or smell) and the fan has only came on twice(very high temp). runs great when not in the city.... Your telling me to check res. tank right? The radiator cap is under insturment cluster right? I can not get to that....
thx again.. you folks are AWESOME!!
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
Sounds like this could be the infamous split in the overflow hose at the rad cap, if the reservoir tank is FULL. You will have to get some plastic off to get to the rad cap area and see if the hose going to the overflow tank has a split in it right at its connection point. This could be the source of the symptoms you are describing, for, if your rad coolant is low, the fan will not come on as early as it should, hence the higher than normal temp gauge readings you are seeing.
Buy yourself a Honda Service Manual and it will show you everything you need to know about working on your bike, even taking off the plastic.
Sounds like this could be the infamous split in the overflow hose at the rad cap, if the reservoir tank is FULL. You will have to get some plastic off to get to the rad cap area and see if the hose going to the overflow tank has a split in it right at its connection point. This could be the source of the symptoms you are describing, for, if your rad coolant is low, the fan will not come on as early as it should, hence the higher than normal temp gauge readings you are seeing.
Buy yourself a Honda Service Manual and it will show you everything you need to know about working on your bike, even taking off the plastic.
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Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
If it is a older model, (older as in time), I would suspect that the radiator is partially blocked.
This was a problem I had with my V45 & V65 Sabres in slow traffic.
If it is a older model, (older as in time), I would suspect that the radiator is partially blocked.
This was a problem I had with my V45 & V65 Sabres in slow traffic.
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
The radiator cap is under the grey trim panel on the right side of the instrument cluster, next to the fake fuel tank cover. To get to it:
1. remove both saddlebags
2. remove seat
3. remove both sidecovers below the seat
4. remove false tank cover (two bolts under the bars, two on the sides exposed after removing sidecovers)
5. remove small side covers by cylinder heads
6. now you should have access to all the screws you need to pull the grey panel off. there is one under the tank cover, a few in the pocket itself, one or two on the sides, and one at the bottom in the footpeg area.
Doing this blind from memory, so I may have forgotten a screw or two, but this should get you most of the way there.
If you don't check the rad level at the cap, you're wasting your time with anything else, its the first step to resolve the issue you're having.The radiator cap is under insturment cluster right? I can not get to that....
The radiator cap is under the grey trim panel on the right side of the instrument cluster, next to the fake fuel tank cover. To get to it:
1. remove both saddlebags
2. remove seat
3. remove both sidecovers below the seat
4. remove false tank cover (two bolts under the bars, two on the sides exposed after removing sidecovers)
5. remove small side covers by cylinder heads
6. now you should have access to all the screws you need to pull the grey panel off. there is one under the tank cover, a few in the pocket itself, one or two on the sides, and one at the bottom in the footpeg area.
Doing this blind from memory, so I may have forgotten a screw or two, but this should get you most of the way there.
OP
OP
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
thx... I'm gonna have to tear it all apart.. I do love my ST.
thx... I'm gonna have to tear it all apart.. I do love my ST.
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
the coolant level in the reservoir should be someplace between the high and low marks on the tank. these marks are very hard to spot... the low is visible by looking in the crack between the colored rt side plastic panel, and the aluminum of the lower side panel ( this panel has the rider pegs mounted to it) it's marked "low" and the tank has a molded ridge that is the low mark. the high mark is also molded into the tank....it's checked by looking inside of the cut out on the plastic panel ( this is about 3x4" and the trailing edge of the tank is visible when looking inside of the cut out...way down at, almost the bottom of the cut out is the "high" mark ( but does NOT have the word "high" on it). if this tank is totally filled, something's wrong. when ever you have the body work off, check everything that you can...this includes the hoses..they do go bad with age, and you don't need to do things twice! you would be very well served by getting a manual not that this can't be done without one, but always nice to be able to read and see pics before taking up tools
the coolant level in the reservoir should be someplace between the high and low marks on the tank. these marks are very hard to spot... the low is visible by looking in the crack between the colored rt side plastic panel, and the aluminum of the lower side panel ( this panel has the rider pegs mounted to it) it's marked "low" and the tank has a molded ridge that is the low mark. the high mark is also molded into the tank....it's checked by looking inside of the cut out on the plastic panel ( this is about 3x4" and the trailing edge of the tank is visible when looking inside of the cut out...way down at, almost the bottom of the cut out is the "high" mark ( but does NOT have the word "high" on it). if this tank is totally filled, something's wrong. when ever you have the body work off, check everything that you can...this includes the hoses..they do go bad with age, and you don't need to do things twice! you would be very well served by getting a manual not that this can't be done without one, but always nice to be able to read and see pics before taking up tools
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ST1100Y
Site Supporter
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
- with cold engine the coolant level should sit at the MIN mark
- with fully warmed engine (fan cycling) the level should not exceed the MAX line
- when engine cooled off again the level must return to the MIN
(note: thus do not overfill, like filling coolant to MAX with cold engine...)
In fact is it an indicator for proper functionality of the cooling system:
- with cold engine the coolant level should sit at the MIN mark
- with fully warmed engine (fan cycling) the level should not exceed the MAX line
- when engine cooled off again the level must return to the MIN
(note: thus do not overfill, like filling coolant to MAX with cold engine...)
OP
OP
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
Hello to all... I have solved the mystery for now. I got to the radiator cap and added coolant. LOL yep, the radiator was empty?? I know! I have ridden several time and no leaks, no smell, not overheating(always between 10/1). So thx all and I intend to hang out here and make some friends now. Thanks soo much:bow1::bow1:
Hello to all... I have solved the mystery for now. I got to the radiator cap and added coolant. LOL yep, the radiator was empty?? I know! I have ridden several time and no leaks, no smell, not overheating(always between 10/1). So thx all and I intend to hang out here and make some friends now. Thanks soo much:bow1::bow1:
ST1100Y
Site Supporter
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
Well, but the STory isn't over yet, cause there must be a reason (read: a leak) why the coolant vanished...
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
.I suspect those elbows and o-rings will reveal their demise once under constant coolant heat pressures.
+1......lol..beat me to it
.I suspect those elbows and o-rings will reveal their demise once under constant coolant heat pressures.
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
No leak, no smell of coolant - but the overflow bottle was full . . . as I said earlier, there is probably a split in the overflow hose at the rad cap. Dmays still doesn't confirm checking that.
No leak, no smell of coolant - but the overflow bottle was full . . . as I said earlier, there is probably a split in the overflow hose at the rad cap. Dmays still doesn't confirm checking that.
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schlep1967
Bill
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
Now that you filled the rad you will smell coolant in the near future. Like others have said, check the line between just below the rad cap and the overflow bottle.
Now that you filled the rad you will smell coolant in the near future. Like others have said, check the line between just below the rad cap and the overflow bottle.
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
while you're nosing around for the problem...swing the snozz down by the overflow tanks fill neck.( cap opened) reg. antifreeze and water smells sweet....if you detect exhaust smell, look farther. not saying it's the problem but it could be what's pushing the coolant out of the cooling system , into the overflow tank. or it could be as simple as the P.O not knowing his over flow from the rad. fill
while you're nosing around for the problem...swing the snozz down by the overflow tanks fill neck.( cap opened) reg. antifreeze and water smells sweet....if you detect exhaust smell, look farther. not saying it's the problem but it could be what's pushing the coolant out of the cooling system , into the overflow tank. or it could be as simple as the P.O not knowing his over flow from the rad. fill
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OP
OP
Re: 1991 ST 1100 overheats when Im not going 45-55 mph. Water pump? Thermo switc
yep.... I agree, but so far NO leaks/smell and NO overheating!! thx so much!
yep.... I agree, but so far NO leaks/smell and NO overheating!!
thx so much!