Slow coolant leak

[MarkT]

Wouldn't ya know, no leaks until I installed the very expensive Evans coolant.  Now getting a slow drip off of the left valve cover.  And this with the cooling system running with very low pressure.  One drip per minute maybe, with the engine cold.  I've been smelling it since I changed it, but figured I spilled a little, shoulda quit smelling by now.  Haven't seen any leak.  Then I'm laying under the bike today, and there it is.  ARGHHH!  And I don't have time to dig into it right now.

Anybody experienced a coolant leak off the valve cover?  Where was the leak?

[Thunderbolt]

I've read several threads that all seemed to end up at the upper radiator hose clamp.  I have not experienced this, just what I remember.  Long screwdriver and maybe move the radiator forward a little to get to the clamp.

[Chrisj CMA]

I've read several threads that all seemed to end up at the upper radiator hose clamp.  I have not experienced this, just what I remember.  Long screwdriver and maybe move the radiator forward a little to get to the clamp.

+1 on this.........mine did it too, sidestand on left, lowest spot, its a gravity thing.....check the top clamp, get a flashlight and look up just forward of the carb bank on the left side the light should tell you if its wet up there

[olddog1946]

Had the same problem in March, it was indeed the upper hose at the thermostat.  Although tightening up the hose worked, I went ahead, ordered and installed new hoses and put in fresh anit-freeze. So, I should be good to go for quite awhile.

[scoot]

I had the same thing last year. Thought it was leaking out of the head. I finally got a light and could follow the line right up to the hose clamp. Sorry thing was the guy that assembled it originally must of been having a bad day. The clamp screw was actually facing the radiator.  So, I also replaced the upper and lower hoses as long as I was in there. I figured with 80,0000 + miles it wouldn't hurt.

[Gary]

Ditto on that upper hose clamp Mark.

Both my standard and IS have done this leak, usually in the colder temps, winter, etc.

In both cases  was able to get to that screw with a couple of extensions and swivel with a right sized crosspoint bit in the socket since it wasn't a clean straight shot at the screw head. I used a wrap of electrical tape around the bit and stays in the socket.

The tape used after the first drop and search occurred...

Visibilty was the tough thing more so on the IS. I used a headstrap light since I only had 2 hands.

Hope that's the fix for you.

[Black Dog]

Mark,

Another place to look is where the coolant tubes enter the thermostat housing.  There are tapered 'O' rings (# 11 (3 of them) & 12 (just 1) in the pic), and that is where my leak was coming from.  Maybe they could be found 'after market', but I got the Honda parts.



Black Dog

[cookiedough]

As suggested, check the radiator top hose clamps for tightness.  My left side as sitting on the bike is not dripping, but my right side is behind the side pod right behind the radiator cap.  I have noticed a few drips on the floor (just a few I think), but somehow the hose clamp looks very tight and the drips are coming from the very tip/front of the hose at the end of the hose behind the hose clamp.  I have not taken the right pod off yet to see if hose clamp is tight, but will have to if I see dripping again.  As suggested, see if you can wiggle the radiator hose on top (or bottom) by hand and then see if the hose clamps are tight.  If my hose clamp is tight, I may try loosening the top hose clamp a little and wiggle the radiator hose on more so at the neck (and check for cracks in the hose since OEM since 2001) and re-tighten the hose clamp and if that doesn't work might put on another hose clamp at the very tip of the hose.  If that doesn't work with 2 hose clamps, then time to replace the hose I guess but that will be last resort since just changed radiator fluid about 4,000 miles ago is all with Prestone silicate free 50/50 mix.

[MarkT]

Thanks all, for the help.  It's definitely leaking from the thermostat housing.  I tightened the upper hose clamp, I'll see if that did it.  I hope I don't have to pull the tank and airbox to replace hoses etc. 

[Mr.BubblesVRCCDS0008]

Just changed my thermostat last week on my interstate no need to pull tank can all be done from the front. I live in south Texas and went to a 160 degree therm to help with the hot temperature that is coming arround now. I think the orginal was sticking a little on me and after 148k miles it was time for replacing anyway.