Coolant level low

[kwaltersmi]

I was at the boat recently prepping her for spring launch and noticed that the coolant in the overflow reservoir is below the "low" line.  I seem to recall it being properly between the "low" and "high" marks last fall.  Have the crazy cold winter temps messed with the fluid or perhaps I have a leak somewhere?  Any cause for concern?

[Ron Hill]

Kwalter : You have an air leak!  The most likely place is where the hose to the reservoir attaches just below the "coolant cap". 
I had the same problem and tried tightening the hose clamp to no avail!  Then I just installed a new hose and all was then OK!

A thought

[Roland Gendreau]

I have noticed the same thing on my boat each spring and I have no idea where the coolant goes.  Mine does not have an overflow bottle.

[Ron Hill]

Kwalter : This is what I should have told you to also do when you change the coolant recovery hose:

Take a fuel diaper and cut it so it will fit under the engine.  Then after the engine is running and shut down inspect it for fuel, or oil, or coolant drips. 

a thought

[Phil Spicer]

 I too have coolant on the pad under the engine. this has happened before. Think it is on the top port side hose. time to tighten things again.

[kwaltersmi]

Thanks everyone. I don't see any coolant on the pan under the engine or anywhere obvious in the bilge. When I remove the coolant cap on the engine, the engine is completely full with coolant, it's just the overflow bottle that is showing a low level.

[crieders]

I found my coolant under the engine
No apparent loose hoses

[Ron Hill]

K : You have a coolant leak at a hose clamp.  Just check and retighten them all!

Tip - You might do what I have done and put a thin piece of leather between the hose and the clamp to keep the clamp from cutting into the hose too much!

A thought

[lazybone]

If you fail to find where your coolant is leaking from, try sending out a used sample of your engine oil to one of the standard testing companies. 
Their analysis will tell you if its getting in your oil.

[John Sheehan]

You may want to check for a leak in the heat exchanger

John

[Marshall Tonner]

I also found engine coolant low and engine compartment clean. The heat exchanger was leaking and the coolant was pooling in the aft cabin.
Marsh

[kwaltersmi]

Looks like my water heater is rusted out at the base and is ready for replacement. I haven't had a chance to look yet this spring, but i'm wondering if i'm loosing engine coolant somewhere in the water heater loop.

[tonywright]

I chase exactly the same mystery every spring. Empty overflow bottle, but full under the "radiator" cap. I replaced that cap last year, and tightened all hoses.  Empty overflow tank again this spring! Never happens during the summer.  Engine has run fine so far for the last 6 summers.  Let me know if you find anything definitive: it remains a mystery - but clearly has something to do with our sub-zero winters.

Tony

[garyw]

Hi
A follow up question to this earlier discussion.   I have an overflow hose coming from below the coolant opening which doesn't go into a overflow container- it's just a hose.   I noticed the level in the tank was low after it had been filled and wondered if the engine doesn't overheat , should I still be concerned.  Could it just be a different equilibrium point .      I haven't run the engine to see where the fluid goes so I guess could still be a leaking hose somewhere.

GaryW
Summer Wind
Catalina 34
1986
Boston, Ma

[Clay Greene]

Our boat also had the hose off the coolant manifold that ran into the engine bilge.  It is there for when the coolant gets hot and expands.  Newer boats have expansion tanks, one of which I purchased and installed so I didn't have to keep cleaning up coolant from the engine compartment.  If you don't have an expansion tank, you're going to need to keep replacing coolant, particularly if you run your engine for long periods.  It was not unusual for us to have six ounces or so if running the engine on a lake crossing.

I learned while flushing our coolant system this spring that it is easy to get bubbles in the coolant system that can lead you to believe the tank is full (i.e., coolant overflows) when it is really not.  My suggestion is to fill it to full and let it settle or start the engine and let it run for a couple of minutes. Then go back and check it again to make sure it really was full.  Otherwise, you may get to find out if your high engine temperature alarm works (ours does just fine).