C34MKII, 2004
Checked the boat in preparation for splash in a couple of weeks. When put away for the winter engine systems were all in great shape, oil and transmission fluids all fresh, etc. Coolant was at proper level after checking both engine and overflow tank.
When checking levels this week I find the overflow tank empty which surprised me. More surprising was when I pulled the radiator cap off and had pressure in a cold cooling system. Enough that coolant would come out if I did not replace the radiator cap.
Thoughts??
Tom : Hmmm !! The WX could have changed enough to cause the coolant to flow out of the internal tank when the cap was opened. However, I don't believe that the WX change would have emptied a full reserve reservoir. I'd look for a leak in that coolant recovery line.
Ron,
Thanks for the response. I have checked most of the line and cannot find anyplace where it looks to be leaking. The resovoir is in the lazarette and I have traced it back.
But, how would you explain the pressure behind the radiator cap. I could understand some pressure with a hot engine, but a layed up engine. When I removed the cap I had flow that only stopped when I put the cap back on.
Thanks,
Tom
Is it possible that when you checked the coolant level in the overflow tank last year, you did it after the engine had been warmed up? In that case, you were seeing the "normal" low level actually when it should have been high. As to the pressure, all I can think of is that you've got a blockage in the overflow tube or the coolant cap on the engine is broken (frozen closed). Just guesses.
Check the connection to the hot water heater, too. See: http://c34.org/bbs/index.php/topic,3769.0.html
I found exactly the same on mine this weekend. Coolant full under the "radiator" cap, and reservoir empty. Have plannned to call the mechanic to see if we can find any problem.
Tony
Tony, I am also contacting my guy, but they are so busy dropping boats in the water right now, it may take a few days for them to look at it. With the current temp at 35 degrees F, you have to wonder why.
Just a thought, and this may be out in left field. Is it possible that the overflow tank flowed back into the radiator as temperatures dropped over the winter, as it is designed to do, and now that anti freeze has expanded and needs to be heated to open the radiator cap and let it flow back up to the overflow tank. This may be way out of line, but I have never checked the levels with the temp in the 30's before, and therefore am trying to figure it out.
Tom
I am hoping that it is exactly that, and nothing else. Last year when I brought the boat up for the winter the system had never been properly bled, so there was no real connection between the overflow tank and the engine, and hence no drop over the winter. I opened the bleed valve once the engine was warmed up last year, and vented the air, and it suck a fair amount of additional antifreeze from the overflow tank. So this was its first winter where the coolant was at a proper level in the engine. Here the temperature drops below zero Fahrenheit in the winter, so if the coolant shrinks it will shrink a lot!
Once my mechanic has had a look, I will let you know what he says.
Tony
Tony,
Although they have not looked at it yet, the yard says they do not think it should be a problem. Hopefully will know before they splash her on Monday.
Tom
Tom
My mechanic could not find anything wrong today. He reckons to run the engine after we are in the water and then we might see something, or most likely not. I sure would like to know what caused it though, and where all that antifreeze went!
We tightened the alternator belt today. I had noticed some squealing at high RPM last year, which I thought was coming from the dripless stuffing box. The rep at the baot show said not possible: it's your alternator belt. Didn't seem slack, but we could tighten it a bit, so we'll see.
Tony
The idea behind a coolant recovery system is that you don't have to open the cap to check your coolant level. All you do is look at the coolant level in the recovery bottle.
Even with a cold engine - if you open the cap you will get some overflow of coolant.
Hi Ron
That's exactly what my PO did. He didn't realize that he had an airlock preventing the flow of coolant from the tank. When I opened the cap, the collant was a couiple of inches below the cap. I bled the system, which then made proper connection with the overflow tank. Moral of the story: check under the cap from time to time.
Tom and I both separately discovered the overflow tank was empty this spring, so opened the cap to see whether all the coolant had drained out. It hadn't. The system was full. So where did the coolant from the tank go? This is still the mystery.
Thanks
Tony
How do you get an airlock in what is essentially an open tube between the reservoir and the manifold?
Guys, we've had numerous discusions on the subjet and I'm posting the link to one discussion.
At that time I tough that the problem had solved itself but I've notice that no matter what...that overflow bottle wants to stay empty.
Like mentioned, I've refilled to the mark quite a few times and one of those mystery of boating...it always disaper and I still don't know where!!!
There is no sign of leaks and the bilge is dry and no sign of the green stuff.
My motor is still fairly new so I doubt that it's going through the lining or else.
So from now on...I check now and then the level under the cap (it's always to the rim) and keep an eye on the gage when motoring.
http://c34.org/bbs/index.php/topic,2947.0.html
Guys : I'd keep an eye on the coolant recovery reservoir. That coolant is going somewhere!! - if not a hose to the water heater, maybe an internal leak in the heat exchanger???
Tony,
My yard guy says that I worry too much. It is normal to have pressure in the system. Let's start her up and see what happens! There may be a leak from the over flow to the engine, but if there is no coolant other than what came out when you opened the radiator ( there was none, I had already checked) then it probably just drained back because it could.
Now, this all sounds great. However, if STUFF happens, his balance increases and mine decreases. Bottom line, I don't think there is a problem. I have never found a leak even though I think there must be one.
Let you know some time next week. Hopefully it gets to the 50's for the splash.
When I had some disappearing coolant in the engine, I rented a radiator pressure tester from the local tool rental outlet. Confirming my suspicions, I had a failed heat exchanger. Later, when I was loosing coolant from the overflow tank and finding it under the engine, I thought it was the hose/clamps and replaced them. It turned out to be leaking from the cap.
I agree with Ron, it's going somewhere! The bottom line is that the engine needs an adequate level of coolant. You can either periodically top it off or chase the leak.
Craig
I'm thinking maybe radiator cap. The coolant is full under the cap. I wonder whether the super cold temperatures do something to the pressure under the cap, forcing the cap open, and allowing the coolant to leak out all the way from the overflow tank. (since it is higher than the cap). Once the temperature rises, the cap seals again, and so the reservoir is still full when we open the cap in the spring. Is this crazy? Could it be due to the coolant not being mixed strong enough for the colder temperature in Canada? (Down to -25 or -30 celsius).
I did see a drop or two of coolant under the engine. The rest probably disappeared into a location in the bilge that will not drain into the main bilge until the boat is back into the water, since the boat is tilted aft on the hard.
Maybe nothing will happen once the boat is in the water. But then my plan then would be to drain the coolant, add a stronger mixture, and replace the cap.
Thoughts?
Tony
Noticed this weekend that there was a small crack in the plastic overflow reservoir - right in the groove where the metal band / wire attaches the unit to the inside of the locker. It was a very slow leak, but as soon as I removed the metal wire, the leak was quite noticeable - worth a check
Bill's point is well taken. This is not some supernatural occurrence or voodoo or magic. If the liquid is disappearing, it IS going somewhere. The linked reference earlier in this thread dealt with possibilities: hose clamps, hoses, leaky HX, connection to hot water heater, etc. If it was my boat, I'd make a thorough list of each one, and then I'd carefully check each and every one of them and not believe some boat "mechanic" who says I worry too much. It's my boat, and my safety, not his, out there.
I too had a similar problem. Took a while to find the problem, which turned out to be hose clamps, a number of them throughout the system. the major leaks were the hot water tank connection, and a splice that was made for the heater when the boat was commissioned. All of them dripped just enough to drain the expansion tank, but not enough to easily show up.
Jack
Stu, I think that you may have read my reply a little to literally. He did say I worry too much. This yard has done work on my, and many other boats, for quite some time. They did not see any big issues, there was pressure and therefore coolant in the tank, and until we started it up we would not know if and where a leak was because there was little evidence of coolant in the bilge or otherwise.
Splashed the boat today, started the engine, and as it warmed the overflow tank filled back up. Not completely full, but about where it would allowing for the coolant that came out when I opened the radiator cap. We ran it for over an hour and found no new leaks. They believe that I should replace the cap as the seal might be bad as the weather cools or the spring could be bad....both of which could allow the overflow tank to drain back into the radiator as the temperatures get below zero and the coolant condenses.
Is that the end...is it ever? Of course I will continue to be vigilent and see what happens with the system. I will change the cap. I will make sure it is topped off. If it goes down it has a leak. We will see.
Tony, I hope yours is similar to mine. Good Luck.
Now wet and cold in northern Michigan
Tomm : Sounds that all is OK. Keep your hands off of the coolant cap and check the level by examining the reservoir level. Every time you open the cap - you screw the coolant recovery system up. Good Luck!!
Ron,
You are going to have to explain how I replace the cap without taking the old one off. Am I missing something?
Thanks for the update Tom. Sounds as though I should take some of the coolant out that I added to the reservoir already. Otherwise it could overflow if it fills back up like yours did.
I have been thinking about the hose leak theory some more. Here's the question: if the hose clamps are leaking, how come the tank is full under the cap? A theory has to explain all the facts...
4 days and counting.
Tony,
Remember, that like me, you must have pulled the radiator cap to see that it was full and under pressure. In doing so I lost some coolant. When my engine heats up the coolant only comes back to the add mark, not the full mark. Somewhere in between is proably safe.
Tom
Launched Saturday, and engine started first attempt. No sign of any issues at all. I had reduced the overflow tank to the add mark. Has not moved from there. No sign of any antifreeze in the bilge, or anything else. If I discover anything new, I will post. Right now we are still busy doing spring commissioning. The tanks still have antifreeze in them, and the water heater is still drained.
Tony
Tomm : Sorry, I didn't see your question.
Replace the cap and then let Physics do the rest.
As the engine heats the air/coolant expands and goes into the reservoir. When the engine cools the vacuum created inside the engine reservoir will suck the coolant it needs back in. It will take a few of these cycles to stabilize the outside coolant reservoir and get all of the air out of the system.
I remove my cap when I need to bleed the internal system ie. changing the exhaust riser, changing coolant hoses or changing the coolant every 4/5 years.
Otherwise I check the coolant level by looking at the reservoir and NEVER take off the cap just to see if it's full !!!