What's with this Coolant Overflow? Expanding/purging after shut-down?

[DaniBoy]

I know this has been discussed some, but I have a couple concerns. So this spring I drained my coolant. Filled with water, idled to fan coming on, drained the water and refilled with 50/50. Rode a few times all ok. Then one day I backed out of my garage and there was a 50-cent piece sized puddle of coolant on the floor. Checked reservoir and was good. I rode anyway and came home and parked. I checked underneath and checked again the next day. Dry. Rode many times since. Dry. Then earlier this week I rode and when I got home, I saw the equivalent of maybe an ounce or so of coolant that had run about a foot over to my floor drain (I failed to see it when I backed out). Reservoir is well above MIN mark cold. Cap is tight. I’ve ridden a few times since with no leakage. This is all happening up front near the mid rear of the frunk - in line with the reservoir. When I flushed and refilled the system, I had the reservoir filled to the MAX mark cold. It doesn’t seem anything is leaking, as leaks would always leak and not just every several rides apart. I’m surmising that the system is just “puking” out excess fluid via the overflow that it doesn’t need, due to expansion. I know the last time this happened, the fan was running when I shut the key off. Of course, shutting off the key also cuts power to the fan. Am I correct in thinking that no airflow after shutdown would result in a buildup of heat that could result in continued expansion, thus purging out the overflow?

[SLICE]

Never shut the bike off when the fan is running, it's running because the engine needs to cool.

That may or may not be your problem.

BUT NEVER SHUT OFF WHEN FANS ARE RUNNING.

[Peter Aawen]

Gotta Slice.

From what you've told us Dani, I'd guess that you simply haven't run the engine for anywhere near long enough after adding the new coolant to properly purge/burp all the air pockets out of the system (cos that usually takes AT LEAST 20-30 minutes of fast idle with the reservoir cap OFF &/or a couple/a few 'open the thermostat & trigger the cooling fan' cycles!) so now you've still got some air trapped in there, and whenever you run the bike for long enough to make that air pocket/those air pockets expand enough, quite possibly due to the continuing heat soak you guessed at after you shut it down, it expands enough to force some coolant out of the reservoir overfliw.... Have you ever checked your coolant level in the reservoir within a minute or so of stopping after a good run? If so, was the reservoir full to above the mark?? Or was it

Dunno if this is an attempt to teach you to suck eggs or not, but for those who DON'T know how to do this 'purge the air pockets from your cooling system...

To fix that/remove any chance of there still being air pockets trapped in the cooling system after flushing/changing:

1. raise the front of the vehicle a little (a couple of inches is usually enough);
2. Remove the coolant reservoir cap & ensure the coolant level is topped up;
3. Start and run the engine for at least TWO fan cycles/about 20-30 minutes, making sure that you keep the coolant level topped up during this entire time.

Nb: You should get some coolant expansion and you may also get some coolant overflow during this purging process, which is what you really want to see, because as any air that may be trapped in the system expands, it'll force all the coolant trapping it in there up & out, until the air can 'burp' its way out of the system; and when it does that, which is the aim of this whole 'purge' process, you need to IMMEDIATELY top the coolant level up again or you'll just be trapping more air in there if you add coolant later, after the reservoir level has dropped again!

Failure to do this Purge properly after changing the coolant can mean that whenever your vehicle does eventually get hot enough to burp all the air out - after forcing out all the coolant in the system that was sitting on top of the trapped air - your vehicle can pretty suddenly end up with insufficient coolant in the system to keep the temperature under control and so it fails to do so... often with catastrophic results!

So if you HAVEN'T ALREADY done this after refilling with fresh coolant Dani, DO IT NOW!

Just Sayin'

[DaniBoy]

Thank you, Peter! I’ve actually put several hundred miles on her since the coolant change. Another question I have is that the overflow tube is connected to the filler neck, so how does the system build pressure when that tube is below the pressure cap?

[DaniBoy]

Never shut the bike off when the fan is running, it's running because the engine needs to cool.

That may or may not be your problem.

BUT NEVER SHUT OFF WHEN FANS ARE RUNNING.

But riding or pulling in to a parking spot, I have no way of knowing if the fan is running or not. I don’t know until I turn the key off and then hear it

[Peter Aawen]

But riding or pulling in to a parking spot, I have no way of knowing if the fan is running or not. I don’t know until I turn the key off and then hear it

If that's the case, just don't shut it off immediately when you pull in & stop! It really doesn't usually take long to cool enough, so instead of riding in full tilt & immediately shutting it down:

1. when you realise you're going to stop soon, back off on the throttle & slow down a bit for maybe a minute before stopping;
2. pull in & park without shutting the engine down;
3. leave it running while you select Neutral & set the Park Brake;
4. get off the Spyder;
5. remove your gloves & helmet etc; and
6. ONLY THEN shut the engine down!

This won't be necessarily stop your cooling system from piddling out (or gushing out!) any excess coolant &/or coolant trapped above an air pocket, but it's generally considered good practice to do this in order to let the engine 'wind down' & cool off a bit after hard running, so it definitely won't hurt it if you were riding a little gentler than that! Personally, I'd STILL do the Purge process NOW regardless, and see if it makes any difference &/or overflows the reservoir as it burps out any trapped air. It can't hurt, but it might save your engine!

Thank you, Peter! I’ve actually put several hundred miles on her since the coolant change. Another question I have is that the overflow tube is connected to the filler neck, so how does the system build pressure when that tube is below the pressure cap?

The Pressure Cap is designed so that it has a spring loaded sealing collar bit that projects down into the Reservoir's filler neck & seals BELOW the overflow outlet. That works to keep the cooling system under the pressure designated on the cap, and it'll only release coolant &/or air once the pressure exceeds that the spring loaded bit creates, forcing the seal to rise up off its sealing seat & thereby exposing the overflow outlet, such that it can release enough coolant &/or air to bring the pressure down below the level the spring loading requires, at which time the spring will then force the seal back down and close off the overflow outlet once again!

So this does actually hint at another potential issue that might be leaving you with a few dribbles of coolant escaping - the Pressure spring in the Reservoir Cap might be getting a bit weak, letting coolant out at a lower pressure & temperature than the specified pressure, but that USUALLY means you'll see the system getting hotter/sooner than it should be, even if it doesn't quite overheat! Still, it's an easy fix - simply take the old pressure cap in and buy a new Reservoir pressure cap from an auto parts outlet, they come in standard sizes and generally the specific pressure is stamped on the top, so you can find a quality a/mkt replacement ('cheap' is not necessarily your aim here, nor is it necessarily good/safe for your engine!) and you don't get forced to go buy an OEM cap.

[hypurone]

You could be fighting with "air pockets" in the system, then when the system "purges" one of these and it returns to the reservoir, it can "burp" the cap and take some coolant with it... Most don't know that there is an actual BLEEDER on the front of the engine block that can be used to purge the system!! It is an 8mm if I remember correctly. I run a piece of clear tubing so I can see as the air passes thru it... I bled mine this way and I needed no more coolant and had no level drops afterward...

[Spyderman2018]

You could be fighting with "air pockets" in the system, then when the system "purges" one of these and it returns to the reservoir, it can "burp" the cap and take some coolant with it... Most don't know that there is an actual BLEEDER on the front of the engine block that can be used to purge the system!! It is an 8mm if I remember correctly. I run a piece of clear tubing so I can see as the air passes thru it... I bled mine this way and I needed no more coolant and had no level drops afterward...

Any chance you could provide a photo or 2 of said bleeder?? I sure a bunch of people besides myself sure would appreciate it!!

[SLICE]

But riding or pulling in to a parking spot, I have no way of knowing if the fan is running or not. I don’t know until I turn the key off and then hear it

You must have some super quiet fans, I can hear mine in traffic wearing a modular helmet whilst listening to Cannibal Corpse.

[BLUEKNIGHT911]

There are a few reasons ( as mentioned by others ) ..... My experience is fill it to where you can SEE it ..... The Spyder system is very capable of EXPELING any over-fill without issue. If you have animals that roam around clean and flush the floor where the over-flow is ..... they will die a horrible death if you don't ..... good luck ... Mike

[hypurone]

Any chance you could provide a photo or 2 of said bleeder?? I sure a bunch of people besides myself sure would appreciate it!!

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[Spyderman2018]

Thanks Pete! I'm assuming easiest access is on the right side??

[Peter Aawen]

Thanks Pete! I'm assuming easiest access is on the right side??

Is there anything EASY about getting under the tupperware of your Spyder??

Lifting the Right side Black Service cover below the RT's RH Headlight once the frunk lid is open will give you some access to the Reservoir Cap; but if you're anything like me, you really might want to have a dexterous young assistant with hands that are still small enough to fit in there without leaving lots of bark & claret to mess things up! Having a teenage Nephew/Niece or a reasonable facsimile there-off on hand who's interested in learning about mechanical stuff is usually a good idea; or even just having a good surrogate who's a little bit interested or can be convinced will probably do in a pinch!

[K80Shooter]

You must have some super quiet fans, I can hear mine in traffic wearing a modular helmet whilst listening to Cannibal Corpse.

I agree, I'm legally deaf and I can hear them.

[RangerRick]

On my 2013 most the time the fan comes on after I turn it off, not before I turn it off, but has never puked out any coolant.