Coolant leak near thermostat?
 

Hi everyone, long time lurker first time poster. I have a lovely 1998 Superhawk with 18k miles that is leaking some coolant :( . It looks like it might be coming from the crankcase breather tube above the thermostat which makes no sense. It seems like it leaks more when it is sitting, usually a few drops per day on the garage floor. Any ideas?

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Sorry for the pics being upside down I could not figure out how to rotate them.

It is dripping down the crank cover on the left side. The hoses connected to the radiator look dry. The thermostat also looks dry.

Looking at picture #2 I can see that the rubber tube coming from the cam cover breather has it's clamp out of position. You can see the mark in the tube where it should reside. It could be blow by from the crankcase escaping from that joint and dripping down crankcase blow by can have a great deal of H2O moisture content to it especially in the humid summer months...

If that hose clamp isn't on properly it will blow back. I think the drip is residual discharge dripping after the bike stops moving. Pic 2 shows that hose looking pretty wet. If that one's loose you might check to see if others are loose too.

Thanks guys, I just fixed the hose clamp. Would coolant be leaking out of that hose? Or would that be mostly gas? As far as what is on my garage floor I have smelled it and felt it and I am 99% sure it is coolant and not gas or oil

Give everything a good wash, run it then check again!

If it smells sweet then it's coolant. To awnser the hose question: yes that hose will leak coolant if the clamp is not seated properly.

As I said previously, with that one being not in place then check the other hoses to see if they are not clamped properly regardless if you do your own maintenance or not. One missed clamp can mean more. If not, oh well at least you checked.

The tube connected to the bottom of the airbox is the crankcase breather, you would normally only get an oil mist discharging, which is what the photos seem to show. Actually that is a lot of oil, I wonder if the cam cover is snugged down nicely?

Coolant on the other hand can discharge from the hoses between the heads and the thermostat with age, and this would drain out from the V down over the left side engine cover (as mine did).

A friend of mine owned a 98 for a while and he too had some light weeping where Cadbury described. If you have the means it's probably time for some new hoses.

Out of the hose pictured (the one with the misplaced clamp and that starts at the cam cover) passes a pressurized mixture of fuel/combustion gases know as blow-by, vaporized lubricating oil and moisture, it is slimy, slippery mix of stinky stuff and normally it goes up the hose (against gravity) driven by the pumping action of the engine and into the airbox's stinky stuff accumulator bottle where the liquidy part separates, then the vapor part gets expelled into the airbox to be consumed by the engine's combustion process and then expelled out of the exhaust, except for the part that becomes part of the blow-by for the next cycle... So if it is leaking it's not coolant... If you had a coolant leak big enough to put coolant into this hose you would be seeing white smoke coming out of your tailpipe and your coolant would be low... Misplaced clamp means that the mean bitch named gravity is working against you keeping you engine clean...

I also am experiencing a small weep in the same area. I'm thinking it is the hose at the bottom of the coolant catch bottle.

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I found the leak! I just checked where you guys said and there are two hoses that are leaking. The coolant running down the side is new since yesterday when I wiped it all off and have not ridden, so it seems like a good amount. Any suggestions as to why it is leaking from those two hoses so much? And what to do?

Also as far as the breather hose it was completely disconnected so I wiped it off and put it back on with the clamp. All other clamps and hoses look good. Strangely the air hoses on both sides were disconnected which I am guessing means the PO did away with the PAIR?

The hoses will age and compress under the clamps, to the point where they no longer seal nicely. I'm guessing these particular joints get a lot more heat damage being buried in the V compared to the more external hoses. You can try to nip the clamps up a bit tighter but the best answer is to replace the hoses with new. I bought mine from Partzilla and spent a rainy Sunday morning replacing them. You will need to extract the airbox and carbs to do the work.

Since the hoses are open at the end how would replacing them prevent further leakage? They would still empty into the V right? What are they even for/connected to?

Sorry V-Twin, once of us is confused (and I'm not saying it is you).

Coolant can only leak from the water hoses, either the big bore pipes that lead to/from the thermostat, or the smaller hoses that lead to/from the carbs to stop them icing up. None of these are open-ended.

On my bike I replaced the big bore pipes between the cylinder heads and the thermostat as these were leaking. Once you pull the airbox and carbs out, I'm sure you will see the tell-tale signs of dried coolant around the source of your leak.

I am definitely the confused one, lets assume it might not be coolant. The leak appears to be coming from the air vent tubes connected to the carbs, which I am guessing means it is fuel? Here is a pic of the tubes and the diagram in the manual. In the other picture I posted you can see a drip about to drip off one of the tubes. I am assuming my carbs may need work if it is fuel but like I said at this point I really have no idea what this mystery liquid is, or what combination of liquids it is.



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The liquid on the alternator cover in post 13 looks exactly like green coolant as it has been drying out. Fuel would not leave a chalky residue like that.

The pipe that you see in the post just above is the air vent and they are meant to be just tucked in to the bracket between the carbs. I've not had my VTR's carbs apart but I believe the air vents function as overflows for the float bowls. So it would be possible for fuel to come out of them if one of the float valves was not closing in the float bowls and the vacuum diaphragm on the fuel petcock was not working.

When I first bought my VTR I did have a fuel leak from one of these pipes, but you would know if it was fuel by the strong smell. If there is no strong gas smell, I still think you are looking for a coolant leak.

Alright so if it is in fact a coolant leak I am assuming pulling the carbs is the only way to find it? Are there any coolant tubes that lay above the air vent tubes that could be leaking down onto them?

Pulling the carbs off is not that big a deal.
Remove the seat, prop up the front of the tank, shut the fuel petcock, unhook hoses from the petcock, then remove rear bolt and remove the tank.
Remove the airbox lid and the filter
Remove the air funnels, then lift the airbox lower out. Remove the crank breather hoses.
Loosen the carb isolator bands and then prise up the carbs
At this point you should be able to swing the carbs out of the engine bay with hoses/cables attached, and have access to all of the water pipes.