1800 spits up

[Asphaltmaniac]

My 06 spits coolant out of the overflow vent when the temp gauge goes to the First mark above halfway. I have checked the engine temp with my infrared gun at that mark and its in the 210-220 area which does not seem excessive to me. The rad caps been pressure checked and its good. I just don't get how the system could generate so much pressure at a fairly low temp forcing coolant out. What am I missing

[WingAdmin]

Is the coolant reservoir overfilled?

Has the reservoir ever been removed, or the tubes to it disconnected?

[Asphaltmaniac]

Is the coolant reservoir overfilled?

Has the reservoir ever been removed, or the tubes to it disconnected?

Sure I've had the tank out many times. So what I do is top off the system from the top. Which can take awhile since I can only seem too dribble coolant in. Then get it fully warmed up and when its cooled down ck my reservoir level. I always have to add more and continue doing that until the system wont take anymore coolant. Then as far as I know reservoir and cooling system are at the correct level. And always used distilled water when changing coolant. The two relief tubes are only a few years old and in good condition. But that still wont answer why it spits out at such a low temp especially when the cap checked out good at my dealer. In fact the service manager told me it held pressure right up to the release point.

[Steve F]

I have never had the temp rise above the half-way mark. In my opinion, a mark above the half-way is an overheating situation. I'm thinking that you have air trapped in the system somewhere and the system has an air pocket that can essentially "erupt" when the coolant comes in contact with the hot space occupied by the trapped air. Pressure testing and leak-down tests won't indicate an air pocket. I would recommend looking into a vacuum type coolant filling device that sucks out air before refilling with coolant. I made one using a valve and a radiator cap plug with tubing attached to a vacuum source. Sucks the coolant out of the jug and right into the cooling system.
Here's a link to the commercially available unit (that I copied for my personal use)..... https://www.tooltopia.com/uview-550000.aspx
Their price is about $120 mine cost me about $20

[Asphaltmaniac]

I have never had the temp rise above the half-way mark. In my opinion, a mark above the half-way is an overheating situation. I'm thinking that you have air trapped in the system somewhere and the system has an air pocket that can essentially "erupt" when the coolant comes in contact with the hot space occupied by the trapped air. Pressure testing and leak-down tests won't indicate an air pocket. I would recommend looking into a vacuum type coolant filling device that sucks out air before refilling with coolant. I made one using a valve and a radiator cap plug with tubing attached to a vacuum source. Sucks the coolant out of the jug and right into the cooling system.
Here's a link to the commercially available unit (that I copied for my personal use)..... https://www.tooltopia.com/uview-550000.aspx
Their price is about $120 mine cost me about $20

I have considered the same thing about a steam pocket erupting up through the system and past the cap. And that filling the system from the drain plug may eliminate any air pockets. And be faster? Filling the 1800's cooling system (for me ) is slow and labor intensive. Dribbling in just ounces at a time while it s-l-o-w-l-y burps it self.... I will check out that tool. And maybe you could post pictures and explain your set up?

[GoldWingrGreg]

The system needs pressure tested. You could easily have leak(s) and not know it. Most chain parts stores will lend and have the equipment to pressure test the system and cap. I usually pressure test the system at 16-20psi and then at 6-8psi. Since a small leak may need to pool before spilling over into another area where it may need to pool again before dripping to the floor, do each test for at least 4hrs.

Although the Service Manual may say 6sec test on the cap, consider that a miss-print. The cap needs to hold and maintain pressure between 16-20psi for much longer then 6 secs.

If you have any leaks, be sure to fix those. When you fans come on, with your hands under the headlamps you should feel equal blow and equal heat.

Inspect your "tube, filler" in the reservoir for any cracks and both ends of the reservoir hoses for cracks. Replace that have cracks at their ends.

Be sure to follow the service manual when filing and checking the coolant. Your procedure is incorrect. The reservoir needs checked when hot, not when cold. The import part is to fill under the rad cap on a center stand when eng. is cold. With cap on, start and run 2-3 mins snapping the throttle several times. As soon as you see the temp needle move, turn it off, fill under the rad cap, install the cap, then restart and let run until the fans blow. Thats when I check and add to the reservoir to the top big notch.

However, I have much more success if I refill this way. I fill the reservoir with 1/2 qt. While the engine is cold, fill under the cap ... install cap, start and run 2-3mins while snapping the throttle several times, or until the needle begins to move. Turn off, remove rad cap and fill as needed. Then start it and allow it to run until the fans come on. Here is where my instructions will different. Now I take if for a short ride 5-10mins. Return, allow it to cool over night, then follow the procedure above. You will probably find the coolant under the cap is low. Fill it, run it 2-3 mins snapping the throttle, turn it off, refill if needed, then run until the fans come on, and then fill the reservoir as needed. This way assures that there is no trapped air. Honda's method relies on a snapping throttle, my way does that and the ride also helps too.

Keep in mind, that a cooling system cannot function properly unless it can remain under pressure. Any leak, or a bad cap, or air getting into the reservoir lines from cracks will kill its efficiency. If none of that help, the next thing to do is to remove the radiators and inspect their grids for proper air flow. They can get very dirty on higher mileage Wings. Also, there should never be chrome or anything added that blocks air flow in/out of them.

[Asphaltmaniac]

The system needs pressure tested. You could easily have leak(s) and not know it. Most chain parts stores will lend and have the equipment to pressure test the system and cap. I usually pressure test the system at 16-20psi and then at 6-8psi. Since a small leak may need to pool before spilling over into another area where it may need to pool again before dripping to the floor, do each test for at least 4hrs.

Although the Service Manual may say 6sec test on the cap, consider that a miss-print. The cap needs to hold and maintain pressure between 16-20psi for much longer then 6 secs.

If you have any leaks, be sure to fix those. When you fans come on, with your hands under the headlamps you should feel equal blow and equal heat.

Inspect your "tube, filler" in the reservoir for any cracks and both ends of the reservoir hoses for cracks. Replace that have cracks at their ends.

Be sure to follow the service manual when filing and checking the coolant. Your procedure is incorrect. The reservoir needs checked when hot, not when cold. The import part is to fill under the rad cap on a center stand when eng. is cold. With cap on, start and run 2-3 mins snapping the throttle several times. As soon as you see the temp needle move, turn it off, fill under the rad cap, install the cap, then restart and let run until the fans blow. Thats when I check and add to the reservoir to the top big notch.

However, I have much more success if I refill this way. I fill the reservoir with 1/2 qt. While the engine is cold, fill under the cap ... install cap, start and run 2-3mins while snapping the throttle several times, or until the needle begins to move. Turn off, remove rad cap and fill as needed. Then start it and allow it to run until the fans come on. Here is where my instructions will different. Now I take if for a short ride 5-10mins. Return, allow it to cool over night, then follow the procedure above. You will probably find the coolant under the cap is low. Fill it, run it 2-3 mins snapping the throttle, turn it off, refill if needed, then run until the fans come on, and then fill the reservoir as needed. This way assures that there is no trapped air. Honda's method relies on a snapping throttle, my way does that and the ride also helps too.

Keep in mind, that a cooling system cannot function properly unless it can remain under pressure. Any leak, or a bad cap, or air getting into the reservoir lines from cracks will kill its efficiency. If none of that help, the next thing to do is to remove the radiators and inspect their grids for proper air flow. They can get very dirty on higher mileage Wings. Also, there should never be chrome or anything added that blocks air flow in/out of them.

First let me say I have been having this problem for a few years now...So last dec I stripped the bike down to the engine..At almost 12 years old and 180 on the clock I decided some preventive maintenance was on order. So stripped it down to the top of the engine replaced all cooling system hoses including the reservoir hoses along with any "O" rings, clamps and other plastic pieces along with the pump and thermostat. Cleaned out the radiators they are very clean internally as far as I could tell. What was completely clogged was the area of cooling fins that are out side of the fan diameters. 1000's of noseeums piled up it there and dirt. What a surprise! Then all back together pressure checked the system by letting it sit all night...A done deal....But you know you may have point about the cap...Something for me to explore..thx!
I think you and I are not far apart when it comes to refilling the system. Have done it thru cap or reservoir many times and bike on side and center stand.
A pain in the neck no matter how its done. And yes both fans push the same amount of air...Ive also checked both rads with my infrared gun and both rads have always been just a few if not the same temp in the same spots...So by that Im guessing they are the same clean internally and both are flowing the same amount of coolant. When the fans kick in the temp drop rapidly. Also checked the engine in various spots and it too is very temperature consistent.
The cap is three years old but that dosent mean it couldn't be defective in some way...
I also do my automotive repairs and I have at least twice as I recall bought defective thermostats. Got a bum starter motor once...so will swap it out witha factory part and go from there...Appreciate your help thank you very much...

[GoldWingrGreg]

Yes ... we probably are pretty much on the same page. However, I'm gonna stress again the need to pressure test the system to know there are no leaks, and that the cap is good too. The air flow through the rads needs to not be obstructed by aftermarket "bling." I probably pull more engines for trans repair on GL1800 then anyone in the world, and unlike the automotive field, I've never replaced a thermostat as PM, and have yet to see one fail.

Therefore, if your system and cap hold pressure, and the reservoir hoses fill and syphon correctly, and the system is filled correctly, and the fans blow equal and hot, and there are no obstructions for air to flow through the rads (other then the OEM plastic grids on entry and exit), you are probably down to poor heat transfer which is usually caused by a lack of maintenance. That means that the internals of the rads are contaminated and/or the water jackets are too. Honda says the coolant needs changed every 2yrs of 24k whichever comes first. In some cases they really mean that.

Here is a picture of water jackets from a cooling system that did not have coolant changed as Honda requires, and one that did. The 3rd is one of the worst I've seen.

I reread you original post. I don't ever recall seeing an infrared reading of 210-220. Our thermostats are marked 78c = 172 deg. Hopefully this info helps.

Does your gauge stay below the middle mark while on a center stand even after running for a long time (more then 20 mins and less the 60) ??? It would be normal for your fans to cycle on/off several/many times. At time you might be able to hear that they have variable speeds. Under these conditions will the coolant begin to spit out of the overflow hose ???

[Asphaltmaniac]

Yes ... we probably are pretty much on the same page. However, I'm gonna stress again the need to pressure test the system to know there are no leaks, and that the cap is good too. The air flow through the rads needs to not be obstructed by aftermarket "bling." I probably pull more engines for trans repair on GL1800 then anyone in the world, and unlike the automotive field, I've never replaced a thermostat as PM, and have yet to see one fail.

Therefore, if your system and cap hold pressure, and the reservoir hoses fill and syphon correctly, and the system is filled correctly, and the fans blow equal and hot, and there are no obstructions for air to flow through the rads (other then the OEM plastic grids on entry and exit), you are probably down to poor heat transfer which is usually caused by a lack of maintenance. That means that the internals of the rads are contaminated and/or the water jackets are too. Honda says the coolant needs changed every 2yrs of 24k whichever comes first. In some cases they really mean that.

Here is a picture of water jackets from a cooling system that did not have coolant changed as Honda requires, and one that did. The 3rd is one of the worst I've seen.

I reread you original post. I don't ever recall seeing an infrared reading of 210-220. Our thermostats are marked 78c = 172 deg. Hopefully this info helps.

Does your gauge stay below the middle mark while on a center stand even after running for a long time (more then 20 mins and less the 60) ??? It would be normal for your fans to cycle on/off several/many times. At time you might be able to hear that they have variable speeds. Under these conditions will the coolant begin to spit out of the overflow hose ???

Sorry but I think we've lost the ball in the rough...ha! The reading of 210-220 was taken when the temp gauge reads just over the first mark past the halfway mark and I'm loosing coolant. And let me be very clear at that time its dribbling out not spitting like its really hot. Should not of used the word spits..giving you the wrong image..sorry. I travel through some mountain roads out here and temps will go up when ascending 5000 ft over so many miles of twisting roads. I see the temp rising ,pull over to let the fans kick on, look down and its dribbling...What!?! That cant be right? Temp starts to drop and it stops pretty much that fast. Really just a few seconds is all it takes. And just to let you know my temp gauge at idle, all day if need be, is just under the halfway mark. Its at that same spot on the open road or around town. Never ever a worry in those conditions.
I'm back to your cap comment..Ok Honda gives me the thumbs up but you question how long it holds pressure...They did a quickie pump test and there ya go and show me the door...ha! So although its only three years old I'll swap it out.

[GoldWingrGreg]

Sorry but I think we've lost the ball in the rough...ha! The reading of 210-220 was taken when the temp gauge reads just over the first mark past the halfway mark and I'm loosing coolant. And let me be very clear at that time its dribbling out not spitting like its really hot. Should not of used the word spits..giving you the wrong image..sorry. I travel through some mountain roads out here and temps will go up when ascending 5000 ft over so many miles of twisting roads. I see the temp rising ,pull over to let the fans kick on, look down and its dribbling...What!?! That cant be right? Temp starts to drop and it stops pretty much that fast. Really just a few seconds is all it takes. And just to let you know my temp gauge at idle, all day if need be, is just under the halfway mark. Its at that same spot on the open road or around town. Never ever a worry in those conditions.
I'm back to your cap comment..Ok Honda gives me the thumbs up but you question how long it holds pressure...They did a quickie pump test and there ya go and show me the door...ha! So although its only three years old I'll swap it out.

Thanks for clarifying. Our coolant sensor has 2 circuits in it. One for the gauge and one for the ECM to control the fans. It sounds like your temp gauge circuit is reflecting proper coolant temp. So that leaves a problem with the actual cooling system. Caps on GL1800 fail like ones on cars. In other words, failure is common, and if a cap is bad, coolant not kept under pressure can dribble at that temp, and over time lead to a low system which cannot provide proper cooling.

[GoldWingrGreg]

Sorry but I think we've lost the ball in the rough...ha! The reading of 210-220 was taken when the temp gauge reads just over the first mark past the halfway mark and I'm loosing coolant. And let me be very clear at that time its dribbling out not spitting like its really hot. Should not of used the word spits..giving you the wrong image..sorry. I travel through some mountain roads out here and temps will go up when ascending 5000 ft over so many miles of twisting roads. I see the temp rising ,pull over to let the fans kick on, look down and its dribbling...What!?! That cant be right? Temp starts to drop and it stops pretty much that fast. Really just a few seconds is all it takes. And just to let you know my temp gauge at idle, all day if need be, is just under the halfway mark. Its at that same spot on the open road or around town. Never ever a worry in those conditions.
I'm back to your cap comment..Ok Honda gives me the thumbs up but you question how long it holds pressure...They did a quickie pump test and there ya go and show me the door...ha! So although its only three years old I'll swap it out.

Thanks for clarifying. Our coolant sensor has 2 circuits in it. One for the gauge and one for the ECM to control the fans. It sounds like your temp gauge circuit is reflecting proper coolant temp, and that your fans are probably operating correctly. So from here, it leaves a problem with the actual cooling system ... it's ability to hold coolant, transfer heat in/out of coolant as well as transferring coolant in/out of the reservoir, and retain pressure to keep it from boiling over.

A cap can affect all 3 of those as well as a coolant leak. Caps on GL1800 fail like ones on cars. In other words, failure is common, and if a cap is bad, coolant not kept under pressure can dribble at boiling temp, and over time lead to a low system which cannot provide proper cooling. GL1800 caps are not cheap, but it sounds like you possibly have a bad one.

[Asphaltmaniac]

Sorry but I think we've lost the ball in the rough...ha! The reading of 210-220 was taken when the temp gauge reads just over the first mark past the halfway mark and I'm loosing coolant. And let me be very clear at that time its dribbling out not spitting like its really hot. Should not of used the word spits..giving you the wrong image..sorry. I travel through some mountain roads out here and temps will go up when ascending 5000 ft over so many miles of twisting roads. I see the temp rising ,pull over to let the fans kick on, look down and its dribbling...What!?! That cant be right? Temp starts to drop and it stops pretty much that fast. Really just a few seconds is all it takes. And just to let you know my temp gauge at idle, all day if need be, is just under the halfway mark. Its at that same spot on the open road or around town. Never ever a worry in those conditions.
I'm back to your cap comment..Ok Honda gives me the thumbs up but you question how long it holds pressure...They did a quickie pump test and there ya go and show me the door...ha! So although its only three years old I'll swap it out.

Thanks for clarifying. Our coolant sensor has 2 circuits in it. One for the gauge and one for the ECM to control the fans. It sounds like your temp gauge circuit is reflecting proper coolant temp, and that your fans are probably operating correctly. So from here, it leaves a problem with the actual cooling system ... it's ability to hold coolant, transfer heat in/out of coolant as well as transferring coolant in/out of the reservoir, and retain pressure to keep it from boiling over.

A cap can affect all 3 of those as well as a coolant leak. Caps on GL1800 fail like ones on cars. In other words, failure is common, and if a cap is bad, coolant not kept under pressure can dribble at boiling temp, and over time lead to a low system which cannot provide proper cooling. GL1800 caps are not cheap, but it sounds like you possibly have a bad one.

i
Grabbed a new cap from the dealer yesterday and its on. Time will tell if that was the problem. Just for fun, will visit auto zone for a cap pressure tester and ck the old one and see if it does hold pressure over time.
Thank for your time Goldwingrgreg.