Leak from under rad cap | GTAMotorcycle.com

Leak from under rad cap

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palmpalm

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I was riding along the other day when I was hit in my leg and most of my right side with liquid. When I got off the bike I discovered coolant all over the right side of m 1980 GL1100i. Seeing that the rad cap was leaking and having had Ted at Rosey Toes check the pressure, we decided that the rad cap was no good and I ordered a new one. In the meantime I put on a new overflow hose (from the rad neck to the overflow tank) just in case it was cracked. Today I put on my new rad cap from Honda and the leak it still there! Coolant is coming out from under the rad cap. I don't know what to do now. I have attached pics where you can see the greenish coolant coming out and trickling down the neck of the radiator from under the cap. Thoughts and advice are much appreciated!photo.jpgphoto1.jpg
 
jake, you should have had ted pressure test the system, not just the cap. you may need some welding done around the filler spout or a new/used rad, after all, the bike is 32years old.
 
Stewart said:
jake, you should have had ted pressure test the system, not just the cap. you may need some welding done around the filler spout or a new/used rad, after all, the bike is 32years old.
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Hey Dave! How's it going? Are you gonna be working at Ted's this season? I have not seen you around. If you are working I will bring the bike to you. When are you around?
 
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jake, i'm down for the count. i have cancer and was close to death within a few days in march. i won't be back this year because of chemo, i need to stay alive, thanks all the same...dave
 
Stewart said:
jake, i'm down for the count. i have cancer and was close to death within a few days in march. i won't be back this year because of chemo, i need to stay alive, thanks all the same...dave
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Dave, I am sorry to hear that. I wish you all the best.
 
I figured I might have put the cap on wrong/not tight enough so I took off the rad cap and inspected it and the rad neck for deformities and couldn't find any. Then I put the cap back on and now, to my surprise, it is leaking from the other side! Whereas before it was leaking from the right (break hand) side, it is now leaking from the left side! As soon as the engine heated-up there was basically a fluid stream dripping down from the rad cap-rad neck lip/junction. What in the world is going on?
 
Spoke with Ted today. He said he is "scratching his head" trying to figure it out. He tested the rad and all, he doesn't know what the problem is. Says he will take another crack at it tomorrow morning.
 
Ted and Kevin took out the thermostat and said the leak was now fixed, I took the bike home. As soon as I hit the 400, bam! coolant all over the place again. Errrr .

I took it back and Ted says it must be the head gaskets so now he is going to replace those. Man I am getting frustrated and wish I could afford a new bike. I don't even understand how it coul be the headgaskets since the leak is from the rad cap.
 
So after thinking about this a lot and hearing from Ted, Kevin, Jamie, and, indirectly, Dave (howdee Dave!, heard you were at the shop today) that they are "scratching their heads" and don't know what the problem is "but it must be the head gaskets because we checked everything else" I picked the bike up today because I don't want to pay a lot of cash to start taking the engine apart when we don't know what the problem is, or whether it is even in there. It's going to cost a fair bit to do the head gaskets and, while I don't mind paying that money if it fixes this leak problem, it doesn't seem like we even know that it will.

I really don't know what to do now. Are there any mechanics that are particularly experienced with this kind of thing or with old Goldwings that someone here could suggest? I have been a customer of Ted's for many years and have never gone to anyone else so input is appreciated.
 
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So is it leaking from the housing for the radiator cap, between the radiator cap and the housing that it screws into?

Make sure the little hose going between the radiator cap housing (just below the radiator cap) and the overflow tank is not clogged. I see that you replaced it - make sure it isn't kinked or pinched.

Make sure the overflow tank itself has a vent that is not clogged.

Make sure the radiator cap is the correct one for the vehicle. It's hard to get this wrong, but you never know.

Make sure the radiator cap housing is not warped and doesn't have a hairline crack (that opens up under pressure). This would be my prime suspect.
 
Brian P said:
So is it leaking from the housing for the radiator cap, between the radiator cap and the housing that it screws into?

Make sure the little hose going between the radiator cap housing (just below the radiator cap) and the overflow tank is not clogged. I see that you replaced it - make sure it isn't kinked or pinched.

Make sure the overflow tank itself has a vent that is not clogged.

Make sure the radiator cap is the correct one for the vehicle. It's hard to get this wrong, but you never know.

Make sure the radiator cap housing is not warped and doesn't have a hairline crack (that opens up under pressure). This would be my prime suspect.
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Thanks for the reply. It seems like the leak is just from in between the cap and the housing, that is, the seal between the cap and the housing is allow the fluid through once the engine heats up.

How do I check the overflow tank vent?

It is the correct cap.

How do I check for a hairline crack in the housing?
 
Just took the bike for another ride. I pushed it hard. Kept the gears low, rpms high. I took it on the freeway, I took it in stop and go traffic. Rode for about 45 minutes straight. Engine doesn't seem unusually hot. Sounds good, rad fan is working.

So far as I can tell, no leak. Could I be this lucky?
 
I would, as Brian said, immediately suspect the neck of the rad where the cap screws directy onto. Check it for any kind of burr or deformity that could cause a gap in the cap's ability to seat properly.
I had an aluminum GSXR rad that had evidence ofminor crash damage. If the rad cap wasn't situated "just so", it would leak. The filler neck was a little oval from being crashed or hit, and would allow coolant to leak past the cap's seal. I quickly figured out how to screw cap on "just so", and never had leaks afterwards.

if the bike isn't overheating, no oil in coolant and no coolant in oil, no clouds of white exhaust, and only coolant loss visibly at the neck, I wouldn't suspect head gaskets at all.
 
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new rad cap's seal needed to get wet and swell to make the seal? Was too thin, brittle, and dry when it was first installed? I am reaching here.
 
Update:

Road the bike again today and it leaked!

Ran the bike at idle with rad cap off. Watched as the following happened: coolant level rose, then went down below where it has been with engine turned off, then it just sat at that level with no movement at all. One or two air bubbles came up within a few seconds of starting the engine but that was it. I kept the bike running for about 5 minutes and the coolant did not move at all.

Does this help?

Then my dad got a can of this stuff from Canadian Tire that is supposed to seal-up radiator and head gasket leaks. It looks like liquid copper/metal and you poor it into the radiator. I took out some coolant to make room for the stuff, put the stuff in, and ran the bike at idle for 15 minutes as per the instructions. Then I went for a ride and no leak. But it also didn't leak for the past few days until today.

I don't have a clue what is going on and am hoping that this additional information is helpful.
 
Unless the engine gets up to operating temperature, there won't be much movement in the radiator as the thermostat will be closed, preventing and circulation.

As for the stop-leak stuff, it may or may not help. The principle of the stuff is that it will get forced into whatever slight gap there is when the system is under pressure. If it works for you, great! If not, I'd double check that the lip at the radiator cap is nice and level. Also double check that cap gets pulled down level when you screw it on.
 
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