[Fulkrum]

The last couple times I have ridden my 2003 1800c I have occasionally smelled coolant. Extremely light smell...like the hint of the ghost of a wiff lol. I will smell it very rarely when I'm stopped
The coolant reservoir appears to have the correct amount of coolant in it. There is never any leaked coolant on the garage floor, I have never found any coolant on the engine or coolant hoses etc.
At this point my best guess is it is leaking very slightly from the crossover tube under pressure and burning off on the hot engine.
I had always intended to remove the gas tank this off season and flush and change the coolant. Now with the addition of the coolant smell my plan has changed to one of inspecting/refurbishing the coolant system vs just flushing and filling.
I have read in past threads that the coolant crossover tube between the cylinders and it's associated O-rings can be a source of potential issues.
I'm planning on changing the O-rings.
I figured I would change the radiator cap since i'd be surprised if it wasn't the original.
I'll go through and check the tightness of all the hose clamps in the system.
I have a coolant system pressure tester and plan on testing the system.

My question is:
In light of the info I've given and the steps I plan on taking does anyone have any recommendations of weak spots in the system I should check, potential failure points that others have encountered, fixes that have worked for people with similar symptoms in the past etc etc...
I am traveling for the next two weeks and would like to order any parts I might need and gain as much insight into the system as I can so when i get back I can ideally break the bike down, fix the issue and have it back up and running in short order.
Thanks

 

[Hans&Feet]

The radiator cap under the fuel tank is the place to verify your coolant level.
An air leak in a hose from the radiator cap valve to the recovery tank could
be at the correct level and the coolant in the engine could be low.
Someone in the past year replaced the 0-rings on the coolant crossover tube.
Sometimes the radiator cap has crap on it that affects pressure in the system.
A hose clamp could be loose, that happens more often in the winter.

Coolant leak.

2003 1800s, 118k miles Found a small coolant puddle under the bike today. August 1: 392 miles, my last ride. No signs of trouble. (End of season for me, hip replacement.) September 18: My son took it out for maybe 80 miles. No signs of trouble. September 26: Worked briefly on bike, looking into...

www.vtxoa.com

 

[Chicago-Spike]

Same thing happened to me and many others. The leak is from the 2 hoses that go between the cylinder heads. This will drip onto the hot engine and burn off and leave no traces. Tighten the clamps on those small hoses and I'll bet it goes away

 

[rangers4u]

The last couple times I have ridden my 2003 1800c I have occasionally smelled coolant. Extremely light smell...like the hint of the ghost of a wiff lol. I will smell it very rarely when I'm stopped
The coolant reservoir appears to have the correct amount of coolant in it. There is never any leaked coolant on the garage floor, I have never found any coolant on the engine or coolant hoses etc.
At this point my best guess is it is leaking very slightly from the crossover tube under pressure and burning off on the hot engine.
I had always intended to remove the gas tank this off season and flush and change the coolant. Now with the addition of the coolant smell my plan has changed to one of inspecting/refurbishing the coolant system vs just flushing and filling.
I have read in past threads that the coolant crossover tube between the cylinders and it's associated O-rings can be a source of potential issues.
I'm planning on changing the O-rings.
I figured I would change the radiator cap since i'd be surprised if it wasn't the original.
I'll go through and check the tightness of all the hose clamps in the system.
I have a coolant system pressure tester and plan on testing the system.

My question is:
In light of the info I've given and the steps I plan on taking does anyone have any recommendations of weak spots in the system I should check, potential failure points that others have encountered, fixes that have worked for people with similar symptoms in the past etc etc...
I am traveling for the next two weeks and would like to order any parts I might need and gain as much insight into the system as I can so when i get back I can ideally break the bike down, fix the issue and have it back up and running in short order.
Thanks

While many of us don't ride year round due to weather and geography, I compare a water-cooled bike to a gasoline powered car. I would never drive a car for the number of years we have on these bikes, without changing all the hoses and clamps involved. I started to replace them all 3 years ago, but procrastination and life have stopped me after only changing a couple of the longest ones. I had ordered the entire cooling system replacement hoses and clamps from my Honda Powersports dealer for around $165. With all the vibrations of the massive V twin, and the nature of hoses getting hard, old, brittle, some small leaks will develop. If small enough to not leave spotting, they will burn off on the engine, thats why you smell it. You really have to look in the nooks & crannies to be able to spot it.

 

[Merry Prankster]

I always called that Cold Weather Leaks....

 

[TennX]

Somewhere on here was a discussion of different hose materials…my plan was to change to better quality hose materials ,even though it meant cut to length…from memory these materials had a longer life expectancy….unfortunately this is all i remember of the thread….and search didn’t yield results….good luck

 

[fastspek]

I never had to change hoses or clamps on my cars or motorcycles because of a leak even when they were 20 yrs old
Could a hot climate be a factor?

 

[Fulkrum]

The radiator cap under the fuel tank is the place to verify your coolant level.
An air leak in a hose from the radiator cap valve to the recovery tank could
be at the correct level and the coolant in the engine could be low.

I understand, I should have specified in my original post I was using the coolant level in the recovery tank as an observation point. Understanding that if the system is comprimised it may not be reliable.

The leak is from the 2 hoses that go between the cylinder heads. This will drip onto the hot engine and burn off and leave no traces. Tighten the clamps on those small hoses and I'll bet it goes away

This and possibly the O-rings on the coolant crossover tubes between the jugs seem to be the most likley culprit.

I would never drive a car for the number of years we have on these bikes, without changing all the hoses and clamps involved.

I think there is a happy medium that has to be found between preventive maintenance and "If it aint broke dont fix it". Firing the parts cannon isn't something I want to do if for no other reason then because of cost.

Basicly the comments all backup the past reading I've done here which is prety much what I expected. I figured it couldn't hurt to ask though.
Thanks everyone for the input I appreciate it greatly.
If nothing else it should be an easier fix then a similar issue I have been fighting on my Goldwing.

 

[Fulkrum]

$45 for a radiator cap, $55 with shipping
Thats some sticker shock right there... crazy
Gone are the days... I guess lol

Source is PartZilla
When out of curiosity I checked an 1800c a few years newer then mine ( 2007 1800c )
I get a diferent part number ( 19037-GEE-710 ) and a slightly lower price $28.42 .
Dosent seem likley there were any changes, anyone know for sure?

 

[Hans&Feet]

Remember the Honda Civic exhaust we use..
I would take the the rad cap to a NAPA store.
It could be another Civic part.

 

[Merry Prankster]

Amazon.com: Radiator Cap, Replace 19045-PAA-A01, 19045PAAA01 Compatible with Honda Acura - 1994-2005 Accord, 1993-2005 Civic, 2002-2005 CRV, 1995-2007 Odyssey, 2003-2008 Pilot, 1995-2005 TL, 00-05 S2000, More : Automotive

Buy Radiator Cap, Replace 19045-PAA-A01, 19045PAAA01 Compatible with Honda Acura - 1994-2005 Accord, 1993-2005 Civic, 2002-2005 CRV, 1995-2007 Odyssey, 2003-2008 Pilot, 1995-2005 TL, 00-05 S2000, More: Standard - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

[Fulkrum]

Amazon.com: Radiator Cap, Replace 19045-PAA-A01, 19045PAAA01 Compatible with Honda Acura - 1994-2005 Accord, 1993-2005 Civic, 2002-2005 CRV, 1995-2007 Odyssey, 2003-2008 Pilot, 1995-2005 TL, 00-05 S2000, More : Automotive

Buy Radiator Cap, Replace 19045-PAA-A01, 19045PAAA01 Compatible with Honda Acura - 1994-2005 Accord, 1993-2005 Civic, 2002-2005 CRV, 1995-2007 Odyssey, 2003-2008 Pilot, 1995-2005 TL, 00-05 S2000, More: Standard - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Heck ya! $10 bucks beats $50 hands down lol
This has been confirmed to cross reference from the civic etc.. to an 03 1800c?

 

[Merry Prankster]

Idk, have to check. I just search we d for honda Civic caps. Same first numbers.

 

[Fulkrum]

ahh ok thanks, ill have to see if I can find some kinda cross refernece info somewhere.
would sure be nice if it did work though

 

[Merry Prankster]

Radiator cap and common parts.OEM or Preferance?

So, going to have the girl down a few days to do the desmog mod, replace the radiator cap, work on the headlight and display rattle/buzz mods and possibly a couple other small projects for her. First question is OEM 39.00 radiator cap what is recommended or is there another brand that others go...

www.vtxoa.com

Quick read

Vid

 

[Fulkrum]

Thanks, apprecite the info.
I had read the thread you linked already, unfortunatley it dosent give any exact info i.e. I used this exact cap etc etc.
He says he used an early 90's civic cap but dosent give exact details etc.
Intresting video.
Im tempted to try the $10 civic cap and save the $$ but without solid cross reference info it might be a crap shoot.
On the other had GROSSLY overpaying for the correct part number cap buys peace of mind I guess.
Decesions descesions lol

 

[Red Dog]

The last couple times I have ridden my 2003 1800c I have occasionally smelled coolant. Extremely light smell...like the hint of the ghost of a wiff lol. I will smell it very rarely when I'm stopped
The coolant reservoir appears to have the correct amount of coolant in it. There is never any leaked coolant on the garage floor, I have never found any coolant on the engine or coolant hoses etc.
At this point my best guess is it is leaking very slightly from the crossover tube under pressure and burning off on the hot engine.
I had always intended to remove the gas tank this off season and flush and change the coolant. Now with the addition of the coolant smell my plan has changed to one of inspecting/refurbishing the coolant system vs just flushing and filling.
I have read in past threads that the coolant crossover tube between the cylinders and it's associated O-rings can be a source of potential issues.
I'm planning on changing the O-rings.
I figured I would change the radiator cap since i'd be surprised if it wasn't the original.
I'll go through and check the tightness of all the hose clamps in the system.
I have a coolant system pressure tester and plan on testing the system.

My question is:
In light of the info I've given and the steps I plan on taking does anyone have any recommendations of weak spots in the system I should check, potential failure points that others have encountered, fixes that have worked for people with similar symptoms in the past etc etc...
I am traveling for the next two weeks and would like to order any parts I might need and gain as much insight into the system as I can so when i get back I can ideally break the bike down, fix the issue and have it back up and running in short order.
Thanks

I have the same bike and occasionally the smell. Just had the coolant changed and it's still there...and I ignore it now

 

[Sojourner]

I have the same bike and occasionally the smell. Just had the coolant changed and it's still there...and I ignore it now

There's a hose off of the reservoir tank that vents to atmosphere that I suspect may be the source of the coolant smell. I get it once in a while too.