Coolant Low, No Leak?

I think all the thermostat/coolant leak threads have me a bit paranoid, but I have to ask since I'm a technical moron:

I was riding home the other day and smelled that "hot coolant on the engine" odor. Then, again, I also smell the "smoking marijuana in the car ahead of me" odor too, so I figured it could be any other car on the road.

Engine temp was in the normal arc, and everything was running fine.

When I got home, I let the engine cool down, put it on center stand and looked at my coolant level. It was down quite a bit.

I flushed the coolant about 2 years ago/16,000 miles ago.

So, is it normal to lose some coolant over time? Should I be concerned about a leak, even though the ST has never dripped anything on to the floor?

Thanks for considering my question.

I've pretty much have the same issue. Back in August of '06 I replaced my thermostat and also tightened some of the loose hose clamps that I had. Before that time, I used to get the same hot coolant odor after stopping and the only time I had ever seen coolant on the floor was one time when the bike had sat over the winter.

For several months after that I didn't smell any coolant at all and I thought I might have fixed the problem but beginning in the spring of last year I started to occasionally run across situations where I would smell the hot coolant again. To make a long story short, when I pulled the plastic off earlier this spring and checked the level of coolant in the reservoir bottle I was down to just below the LOW line. This was with about 20K miles since the coolant level had been topped off.

I did go back in and tried to tighten some of the hose clamps (especially the small ones by the throttle bodies) but I don't think I've found everything as I still will get the coolant smell once in a while. I personally am not going to lose any sleep over it. The loss rate is so low that if I have to go in and top off the reservoir once a year I'm OK with that. I'll be due for a coolant change anyway by the time it goes low again.

I'd check behind the front wheel and thru the black engine cowl/cover ( just below the radiator. You will probably see at lot of dirt and gunk, and maybe some coolant. I find the coolant makes its way from the front of the motor down under into the belly pan, where it'll dry out or burn off ( exhaust heat ).

If you look thru the black cover/cowl ( behind the front wheel ) and you don't see the silver color of the motor...well I bet thats where your leak is. This is where your water pump is ( well, to the upper left ).

Good points, guys. I'll try to take a gander next time I pull the plastic.

I'll tighten the hoses, and check under the radiator.

:bump

Took the ST over to Rich's winter wonderland today, pulled the plastic to begin routine maintenance, and Rich pointed out that the water-pump weep hole is oozing coolant. Looks like it's been doing it for a while.

According to the owners manual, the mechanical seal on my water pump is shot.

Trying to figure out now if I need a whole new water-pump assembly, or if the mechanical seal can be replaced...

Anyone?

EASt said:

:bump

Took the ST over to Rich's winter wonderland today, pulled the plastic to begin routine maintenance, and Rich pointed out that the water-pump weep hole is oozing coolant. Looks like it's been doing it for a while.

According to the owners manual, the mechanical seal on my water pump is shot.

Trying to figure out now if I need a whole new water-pump assembly, or if the mechanical seal can be replaced...

Anyone?

Click to expand...

So I am seaching "water pump" and up this comes

Again: Great eye on that weep hole, Rich.

You may amount to something someday, young man!

Don't be so quick to condemn the water pump. Leaks from above from hoses in the crotch of the V will leak to the pump and look like the weep hole.

Looks like this is a big enough problem that Honda changed the design for 08 so there is now a hose for the weep hole going to the ground! THEN they even say in the manual that "a small amount of weeping is normal" from this hose.

Seems they were changing a lot of good water pumps under warranty.

In answer to your question, you remove 2 cover assemblies and you can replace the mech. seal and bearings by pressing them in and out. Pretty involved, you'll be looking at the clutch pack when it's apart.

Pete in PA said:

Don't be so quick to condemn the water pump. Leaks from above from hoses in the crotch of the V will leak to the pump and look like the weep hole.

Looks like this is a big enough problem that Honda changed the design for 08 so there is now a hose for the weep hole going to the ground! THEN they even say in the manual that "a small amount of weeping is normal" from this hose.

Seems they were changing a lot of good water pumps under warranty.

In answer to your question, you remove 2 cover assemblies and you can replace the mech. seal and bearings by pressing them in and out. Pretty involved, you'll be looking at the clutch pack when it's apart.

Click to expand...

Thanks Pete.

Rich and I fired up the engine, and let the coolant come to pressure. The drip from the weep hole was pretty obvious. While I'm at it, I'll take your advice and firm up the hoses since everything's coming out already. :-|

Since I'm rolling up the sleeves, may as well reach in deeper.

So what year, how many miles, and what type of coolant have you run?

Just to be clear, you do mean the small round weep hole halfway up the water pump plate and not the oblong one just above clutch housing?

--Mark

Blrfl said:

Just to be clear, you do mean the small round weep hole halfway up the water pump plate and not the oblong one just above clutch housing?

--Mark

Click to expand...

Correct, sir. About the size of a paper-clip hole on the right side of the water pump assembly.

There's a nice clear trail that starts at that hole, cuts through all the road grime on the engine, and drips off the bottom.

Pete in PA said:

So what year, how many miles, and what type of coolant have you run?

Click to expand...

2003 (non-ABS)
42,000 miles
Hondaline Officially Endorsed and Approved coolant only

EASt said:

Correct, sir. About the size of a paper-clip hole on the right side of the water pump assembly.

There's a nice clear trail that starts at that hole, cuts through all the road grime on the engine, and drips off the bottom.

Click to expand...

And you know Erik, I have been thinking about the grunt that was on the front of my motor. I am pretty sure that the "fluid" was starting from the valley drain, so I am pretty sure I will need to check this out. I will take a pic of the staining on our bikes if I run out there today.
I am just going to pull my tank and the airbox so I can have a little looksee at the hoses under the throttle bodies.
Rich

Rich R said:

And you know Erik, I have been thinking about the grunt that was on the front of my motor. I am pretty sure that the "fluid" was starting from the valley drain, so I am pretty sure I will need to check this out. I will take a pic of the staining on our bikes if I run out there today.
I am just going to pull my tank and the airbox so I can have a little looksee at the hoses under the throttle bodies.
Rich

Click to expand...

In the case of my ST, we both saw a pretty clear line of dirt that had been cleansed from the weep-hole down; leading me to think that I may not have to worry about the valley drain...

I should probably check that too, though...

EASt said:

In the case of my ST, we both saw a pretty clear line of dirt that had been cleansed from the weep-hole down; leading me to think that I may not have to worry about the valley drain...

I should probably check that too, though...

Click to expand...

There is no doubt that your leak is from the water pump.

I guess my point was I can take pics of both bikes to show the difference between the 2 leaks, and the points of origin.
Rich

Rich R said:

There is no doubt that your leak is from the water pump.

I guess my point was I can take pics of both bikes to show the difference between the 2 leaks, and the points of origin.
Rich

Click to expand...

That'd probably be helpful - post 'em so that others, who may be having the same problem, can get a clear idea.

So many ways to leak coolant, I guess.

Update:

Turns out the weep-hole leak may be the least of the problems.

Even though I never noticed a distinct coolant leak in the 5 years I've owned my ST, we found more signs of leaking this weekend. After pulling off the radiator we looked into the thermostat area and saw a healthy coat of green, crusty coolant goo.

Dangit.

TurboCity thermostat on order (mine never went bad, but may as well replace it since I'm in there), and will check and tighten all the hoses.

Sigh.

My ST has dodged heat issues, wobbles, thermostat failures, and almost dodged a coolant leak. I thought I was one of the folks with a perfect ST.

Additional weekend maintenance items:

• A slow oil drip was thought to be a cracked oil pan. Dropped the pan off of the motor, and found no cracks. Possible sealant cracking/leaking.
  
• Rear brake caliper rebuilt with new pistons and seals. Works nice and smooth now. Turned out to be crud build-up on the pistons.
  
• Hondaline heated grips in and good.
  
• Valve Clearance: 43,000 miles on the odometer, and everything's in spec! W00t!

Rich wrote:
"I am just going to pull my tank and the airbox so I can have a little looksee at the hoses under the throttle bodies."

Gonna have to do more than that. The only water hose under the throttle bodies is the one servicing the SE thermal valve. To get at the mess of hoses in the V of the engine the throttle bodies will have to come off and the black rubber mat covering the hoses rolled back to expose the connections that need to be tightened. Some of those hoses will have only clips securing them and you may wish to consider replacing those with hight quality helical screw bands.

Seems like an awful lot of work just to save a few ounces of coolant. I'd wait until I had some seriously good reason to pull the throttle bodies and THEN I'd go looking for trouble under the rubber mat. I did once and that's how I know it.

Pete

And... update:

This weekend, we replaced the T-Stat and tightened 4 of the hoses that were accessible from behind the radiator, around the T-Stat. Sure enough, the hose clamps were all in need of a good tightening.

Remounted the radiator, attached all hoses, filled up the coolant system.

The sealant on the bottom of the oil-pan had taken hold, so refilled the oil and changed the filter.

Fired up my naked ST and drove around the lot (I'm not going to submit that for coldest ride ). Let her idle to full temp/3 bars.

Pulled it back in, and let it sit while we started the farkle process. By days' end, not a single drop of fluid leaked.

Appears as if the weep-hole leaking was cold-weather storage induced. Hose clamps around the T-Stat were the likely cause, and oil was leaking from the cracked seal at the base of the oil pan.

LEAK-FREE ST!

.... for now.