Coolant spill in driveway.....any ideas?

I just bought a bike. 2003 VFR 800 with 30k miles. You can read my other thread where I talk about this new bike of mine.

On the drive home, I drove kinda slow, 30-40mph, because I have not ridden in about 7 years, and I am a bit apprehensive. I realize the VFR does not like to be ridden slow, and its kinda hot out (Florida), but not REALLY hot. Bike got up to like 250 degrees!

I get home, park in driveway, with engine running for a few seconds, and coolant starts leaking out the hose near the kickstand, the hose that goes to the overflow tank. It was a good bit of coolant, see photos below.

Any ideas what this is likely caused by? I pulled the plastics off, saw no leakage anywhere obvious, radiator cap looked fine, no coolant splashed anywhere around. Just coming out that hose.

Just to be on the safe side, after all its a new purchase for me, I took it to Honda for a "check out", so there it sits as I await any news. I am hoping its something basic. I know the bike sat for a few months being ridden very little, so probably only ridden a few times since April, but was in full good tune and tour mode right before that as the owner took it on a road trip to daytona.

 

Check the thermostat

 

They wrote on the service paperwork they are going to check the cooling system. So hopefully the t-stat gets checked. Also someone had mentioned it sounded like a possible bad water pump, which would make total sense too, I could see how that could build up pressure in the radiator and cause overflow.

 

Yup it probably leak from the little pee hole. Good luck find a water pump. It in back order about 6 weeks
You might able to find after market one.

 

I am not sure you would get that much coolant out of a little pee hole on the water pump. This might be coming from the overflow of the radiator, indicating a bad radiator cap most likely. Radiator caps loose spring tension and do not hold pressure, causing coolant overflow and drawing air back into the cooling system.
It could be the thermostat as well, but I do not think you would get that much overflow with a faulty t-stat.
Any parts store should have radiator cap tester "aparatus".

 

+1 Great point :thumbsup: I would go over all the easy step to check and rule out all possible cause before I dig in the pump.

 

Well that's no way to start off your new ownership.

Good points above. The fact that she got up to 250 is not right. That's the danger zone. These bikes run hot, so seeing 220 to 230 (especially in your florida heat) wouldn't be that surprising.

You need to find out of the fan came/comes on at 221-222. If it didn't, that's an issue right there. The one time my bike got to 247 was because the fan didn't kick on while sitting in traffic.

Rad cap is great suggestion, and an easy (cheap) fix. But get it tested anyway as mentioned above by mastergregor.

If those 2 items fail to solve the issues, then go for the t-stat. I'm sure the dealer can pressure check the system, but my guess is if you're going to dig into where the t-stat is, you're gonna replace it regardless.

I'm with mastergregor - the spill is from the overflow. Did you work for BP?

 

mastergregor, can you give me a quick 101 on how that works when the radiator cap is bad? I don't know much about cooling systems, but can you explain in basic terms, when a radiator cap is bad, what happens within the cooling system that causes the coolant to overflow and then what happens in the overflow that causes the coolant to go out through its hose?

 

Fan was definitely on, I could hear it, it even stayed on if I recall when I shut the engine off but left the ignition on. Cooled it until the temp dropped, and then the fans shut off.

 

No problems, here are the basics, someone chime in if I missed something.

Cooling system is a closed pressurized fluid system. This means that internal engine channels, radiators, water pump and hoses circulate coolant fluid without loosing it (sort of simplified explanation, but enough for now). Inside this closed system, there should be nothing else except coolant, meaning no air, no oil, no dirt, etc. This closed system should not leak, meaning, if you pressurize it with a test tool, there should be no drop of pressure.

Now, when engine is cold, system is full of coolant, without any air, and is NOT under pressure (well, it is under atmospheric pressure, as we all are). As you start the engine, it heats up, and consequently coolant heats up too, drawing the heat from the engine into the radiators. The "machine" that circulates coolant is water pump of course, bringing cooler liquid from the radiators around the engine, and moving hot coolant from the engine into the radiators, so heat can dissipate.

As any liquid, coolant can also boil. In order to prevent boiling over of the coolant, but also to increase heat transfer efficiency, cooling system is pressurized, since fluids under pressure increase their boiling point. For instance, pure water boils at 212 at the atmospheric pressure, but at 250 if contained under 16 psi of pressure. Now, heat of the engine heats up the coolant and expands it (physics, any object heated up expands it's volume, except hamburger patty . This expansion of the coolant creates the pressure in the cooling system, which is closed, does not leak, and therefore holds this pressure, therefore benefiting the cooling.

On the other side, excessive pressure in the cooling system is bad, since it stresses weak components, like hoses, seals, gaskets, etc. So every cooling system is designed to work up to a certain pressure, and in VFR, that pressure happens to be 16 psi. When pressure goes over 16 psi (for instance if you ride hard, or uphill, or in any other manner that produces extra heat), there should be a means of relieving this extra pressure. This is done through the radiator cap and overflow tank, where radiator cap lets excess coolant flow into the overflow tank until pressure is reduced to below 16psi.

When engine cools down, cooling system creates vacuum inside, because bodies that cool off reduce their volume. In order to prevent the vacuum in the system, and in order to restore the coolant that overflowed to the overflow tank, radiator cap has a reverse valve, that opens when vacuum is created in the cooling system. Coolant from the overflow tank then goes back to the cooling system, replenishing lost/excess coolant as the engine cools down.

When radiator cap is faulty, it does not hold the specified pressure (16 psi in VFR case). As it does not hold the sufficient pressure, as coolant starts to heat up and expand, and pressure in the cooling system starts to increase, expanded coolant starts to overflow to the overflow tank right away with the expansion of the coolant. This means that coolant overflow starts at much lower pressure and much sooner than designed, and therefore, much larger amount of coolant will overflow to the reservoir. As reservoir is a limited size, and usually already has coolant in it, reservoir will get flooded, and extra coolant that can not fit in the reservoir will be drained through RESERVOIR's overflow tube, which is routed behind the water pump and left fairing. If cap can not hold even a little pressure, amount of coolant that leaks can be quite big, like a quart or more, depending on the amount of coolant and size of the engine.

Now, there is a second consequence of low pressure - cooling performance. Since coolant is not under pressure, it takes heat away from the engine at a slower rate than when under pressure, thus reducing cooling performance and making the engine run hotter. At a severe case, when heat is great, coolant can boil and turn into vapor/steam, thus even further reducing cooling performance.

When cooling system with faulty radiator cap cools down, not enough vacuum is usually created to draw back all the coolant that leaked out. Further on, since cap is faulty, it lets air enter the cooling system, causing air pockets and severely reducing cooling performance.

At the end, faulty cap causes you to loose coolant, and get air in the cooling system - worst of both worlds

Good news is that radiator cap is $10 in the auto store and usually stores have a cooling system tester that can test the cap in question. Often you can rent this tester and test your cooling system as well, pressurizing it and making sure it does not leak (making sure pressure stays the same after about 30 minutes).

Let me know if something is not clear here, I tried not to drag out the explanation.

 

Thats was an excellent explanation! I understand much better now. I definitely heard coolant boiling after shutting off my engine, was like I had a pot of water on the stove. Would be super if it turns out to be something simple like the mentioned radiator cap. I have not heard back from Honda yet. This being right before 4th of July, no doubt they are short staffed, and tomorrow of course they are closed, and I wouldn't be surprised if Friday was a skeleton crew as well......so who knows if I will hear anything before the weekend. This forum is amazingly helpful, I am ordering the service manuals (i have them from online but I like to read the paper versions as well), and I hope to be better prepared to tackle these types of first step troubleshooting scenarios. Thank you all!

 

signal, be sure to review all the claim for Honda mechanic, ask question if you are not sure of any major charge on the estimate and keep us posted. You can alway check all the suggestion above by yourself before any major work. Good luck

 

Was the coolant overflow tank modified for the frame slider?

 

As scubalong said, be very diligent with mechanics, and make sure their story checks out. From my experience, mechanics will try to sell you stuff you do not need as soon as they smell the opportunity, just to make a buck. I am not sure how much you trust the guys that are working on your bike, so be careful.

On the other hand, bikes are just a little bit more complex than lawn mowers, so you may consider some wrenching yourself after you get the manuals

 

Update on this thread. I took my bike to Honda, as when this problem happened, I only owned the bike a few hours, and so I wanted an inspection of the bike anyways. Honda says they found no problem. They think the coolant was over filled, as they say I have the proper amount of coolant now in the bike. I asked why would it boil the coolant, and why would that cause overheating? I realize it would potentially cause the overflow to spill, but why overheat. The explanation was they think the t-stat may have been stuck, but that its working fine now. I am keeping an eye on it. I rode tonight, and it only got up a bit past 200 degrees, and that was when I stopped the bike.

I ordered the service manual and also will be ordering the common service manual to learn more. The bill came to $116 (that includes tax, basically 1 hour labor). They told me:

1. front brakes look good, rears have 25% left (the person who sold me the bike told me they did the brakes 1000 miles ago, apparently they only did the fronts)
2. They told me my tires, although in good condition, basically suck, and that I should buy Bridgestones once I burn through them.
My tires are Shinko F009RR 120/70 58W and R009RR 180/55 73W

3. They reminded me that I should do the valve maint in the next few thousand miles (I am just over 30k)
4. Checked re-calls, both were already done to the bike

In the end I think it was good, as they did some basic checks, and that gives me more confidence in the bike knowing its been looked over. The mechanic said his personal ride is a VFR.

I wish the diagnosis of the cooling issue was conclusive. I will just have to watch it. No more coolant has spilled.

 

If your radiator was low but your overflow tank was full it may take a few heating and cooling cycles to balance out. Just ride and keep you eyes on it. Top off any coolant to just above the lower line when cold and don't fill over the upper line when hot. If all is well after a few rides the fluid level should remain constant.

 

Thanks for the update, signal. I would still check out the cap when you get a chance and engine is cold. Sticking t-stat is also something to watch out for. 200-210 is about appropriate range for operating temp, IMHO anything over 230 raises red flags, unless you are on the track

I guess your first repair once you get the literature will be rear pads It is a good start, simple enough and a good wrenching confidence builder. Do it!

 

mastergregor, yes I saw even the shop charges cheap to change the pads so it must be straight forward. I will be looking to do that. What is the recommended pads to use with the bike, Honda OEM? or? Looking forward to it. I also snagged an '03 owners manual on ebay for $25.00 (my bike was missing that, and although I have the electronic version, I like I having the manual to refer to in paper format).

BEST OF ALL - There is a "track day" coming to my area, July 21!!! So I am going to sign up for the "beginners" class (the class you need to take if you have never been to track day before), where they teach you all the basics, I hope to learn alot and build some serious confidence in my bike. I have seen people say you can gain more with 1 track day than a full year of riding........sounds fun!