Coolant for PCX 125

[willie5094]

My coolant is below low after 200 miles and unfortunately my Honda dealer is closed for unknown reasons today, had a look in a car accessory shop and found Comma Xstream G30 antifreeze and coolant ready mixed, any thoughts out there. Or should I just hope my dealer is opened Monday.

[j.d.b.]

Inquire/read whether it is "Silicate Free" coolant and if it will mix with any type of coolant. If so, you are good to go. Look around for where you might be leaking as well (in case it wasn't a bad prep).

[willie5094]

cheers j.d.b for the info, I would have noticed a leak as it lies on a concrete garage floor at home and at work, so as you say it may be bad prep.

[yak]

The hose from my upper coolant tank to the radiator connects at a nipple on the underside of the upper tank. My nipple broke off after 1,000 miles. Adding fluid immediately flooded the garage floor. YOu will know immediately if you have a similar problem. If it doesn't flood out, the low fluid level was probably the fault of someone not checking it at the dealership.

Here is what it says on the back of the Honda coolant bottle:
"Over 95% of coolants on the market use silicate inhibitors to protect against aluminum corrosion. The silicates cause wear to mechanical water pump seals. To prevent this, Honda engineers demanded a corrosion inhibitor without silicates. The result is found inside this bottle."

[WhiteNoise]

willie, may seem silly of me to ask but sometimes the easiest solution to a situation or problem is something "simple" we've just overlooked. Okay having said that here's more:

Info found in 2014/2015 Service Manual
and yes, We're talking Coolant Level Checking:

To get an accurate reading through the coolant window....
Place bike on level ground and on its center stand
The bike should be running at normal temp
The level should be between the Upper and Lower level marks (lines)

Is this how you viewed/read yours? I'm hoping this helps

[maddiedog]

"Silicate Free" coolant

^ That's the main thing.

I'd flush with Honda coolant and use that, but generics (I use Prestone) should be fine -- as long as they're Silicate-Free.

[dantheman]

.....And just a heads-up for everyone on the subject of coolant reservoirs...

Mine leaked out overnight on the garage floor and also I found that the molded-in nipple (for the hose enroute to the radiator) had broken 90% through. I discovered that the tank was not secured very well and had probably bounced around on sharp bumps in the road. The attachment bolt was tight, but the button on the bottom of the tank that slides into an increasingly narrower hole in the plastic frame below was not secured all the way aft. This is because the threaded stud that is welded onto the frame of the bike for the reservoir attachment bolt was not welded at a sufficient angle aft. I tapped it gently back (probably 3/16 inch) with a small hammer and bolted the tank back on. Now the button on the bottom is secured aft in the narrow part of the slot and the tank can't flail around.

Others have reported cracked tanks, and it may behoove everyone to take a quick look underneath above the rear tire at that little fastening button (easily visible) to see if it is all the way aft in the slot. It may save you some trouble down the road.

[maddiedog]

Dan, how old is your PCX? That's a weird failure. Thanks for the warning.

[dantheman]

Mine is a 2013, Maddie. It's a 150 and I'm not sure the attachment of the tank is the same as the 125 (the subject of this thread). But I think everyone with the 150 should quickly check that little button on the bottom to make sure it is seated properly all the way back.

(Also, in my message, I meant to say "the threaded bracket that is welded to the frame", instead of "the threaded STUD that is welded to the frame".)

[yak]

dan, i posted this in your other coolant thread. I found the white end of a plastic "rivet" sticking out under the housing for the upper coolant tank (above the back tire). I don't know what it does but i assume it is the part you are describing.

i could not get the tank to move when i pushed and pulled on it. I was going to put padding around it so that vibration or movement would not cause another failure of the nipple connecting the tank to the radiator. For now, i don't know what caused the failure and i don't want it to happen again.

[j.d.b.]

I took a look at mine, too. The tank is molded with a nipple at the bottom that fits (but doesn't appear to "snap" into) a keyway in the fender. Mine doesn't stay all the way into the keyway but it also resists forward movement out of it.
OP: did you have to do a lot of disassembly to get to the bracket you adjusted?
Also, great catch!

[yak]

@jdb, thanks for the explanation. I had to wait a week for the replacement tank. I don't want that to happen again. Is the problem with the "keyway" that surrounds the nipple? If so, is the nipple breaking off as it continually rubs or bounces against the keyway? What padding could be inserted around the coolant tank that would prevent any motion? Or is the keyway itself flexing.... no amount of padding will prevent that.

[j.d.b.]

What happens is that the bottom "molded-nipple"-hold-down (that you see in the fender) comes out of the keyway and the tank flops around on the bolt holding it at the top. The coolant line attached to the bottom of the tank breaks IT'S nipple off the bottom of tank(releasing the coolant in the tank).
The tank is pretty small and even with liquid in it doesn't weigh much. It's got a substantial hold-down nipple for this application(hah!). It should stay in place in the small-end of the keyway adequately if the upper hold-down is holding even close to the proper position (which the OP seems to have a handle on). This is a very old and common way of mounting all sorts of things in production automotive applications that I'm familiar with. It holds up very well if done correctly. It's a solution for using one fastener where two fastened points are needed. This is cheap and effective if done right. Sounds like an assembly plant problem Honda Q.A. people could easily quell. I'm going to keep an eye on mine as it's pretty solid (though not completely seated in the small end of the keyway). I'm too lazy to gut the bike down yet. I'll include the hold-down adjustment in my next big maintenance unless it goes south sooner.

[yak]

@jdb, if my bottom nipple fails a 2nd time, i have to wait a week for the new tank to be ordered. There is still water in the radiator. Would you say that the scooter can be driven lightly for 7 days using only the radiator? Or should the bike sit until the replacement tank arrives? Or should i order a replacement tank in advance and have it ready?

Is the fact that i can not get my coolant tank to wiggle..... a good sign? I assumed that the broken nipple was the result of some movement of the tank. That's why i was going to pad the entire compartment. Can you move your tank in any direction? Do you see any benefit to padding?

I kept the old tank. It has a circular plastic ring near the filler tube at the top. This must be the upper hold down you describe.

[j.d.b.]

The only reason for that lower hose nipple to break is if it gets forced off-axis. Was your original tank loose and flailing around by the upper fastener only (like the OP's)? Other than that condition causing the nipple to get yanked on by the hose or hitting on something, I don't see how padding or otherwise restraining the tank beyond it's standard, proper mounting will help. If your tank is installed properly it should be fine from here on.
Okay, onto the next question on running without the tank. The coolant expands as it gets hot and the radiator cap vents the excess volume to the overflow tank via that rubber line that runs from the radiator neck to the bottom of the tank. Once the motor is stopped and cools down, the coolant volume in the system shrinks and what was excess coolant vented to the tank is now drawn back into the radiator via that same rubber line. This process keeps the radiator(and the system) full throughout the entire heat cycle (cold to hot to cold). You can run without the tank but you'll be running with less than a full radiator once it heats up and vents some coolant. In many cars, running with less than full coolant can be done quite a long time. In a tiny little tightly-engineered set-up like a PCX, I couldn't say and don't recommend it. I don't know how "low" is too low to pump in this system. There isn't much there to begin with. I'm sure Honda tested for that limit in development but I've never seen it published anywhere. Might be a tight window might be wide(I don't want to find out). Anyone else here have experience running with low coolant on a PCX?
Is any of this helping? We're drifting off-topic pretty good.
Rise safe!