Engine Overheating Light/Alarm

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Aug 4, 2009
9
2 First Series, 32s5 Old Hickory, TN
:evil::neutral:I'm the owner of First 32s5 with Volvo 2000 series 18 hp engine. On two ocasions the light has come on and once the alarm. The engine was shut down and after finding no evidence of leaks the engine coolant level was found to require 2 to 3 quarts of coolant. After a 20 to 30 minute run the coolant has disappeared. I'm thinking that I may have a leak in the heat exchanger. I will appreciate anyone sharing a similar problem. On a previous boat I had to remove the heat exchanger and recall how difficult it was putting back together. How does one check the unit for leakage? and where? I'm located in Nashville.
Thanks for your input.
Larry
 
Jan 22, 2008
169
Beneteau 343 Saint Helens, Oregon OR
Is the engine oil ok? A leak somewhere in the engine will usually make the oil frothy.
I don't know the Volvo at all, but if you can shut the raw water valve on the intake and remove the discharge side hose at the water muffler you may be able to pressurize the engine side enough to push water to the muffler if there is a leak in the Hx. Whatever color your coolant is would then show up there.
My limited experience has been with the can-style Hx where you can pull off the endcaps to examine the tubes without removing the Hx.
 
May 3, 2008
252
Catalina Capri 22 Half Moon Bay
Overheating...
Assuming you check your oil frequently, probably not the oil.
This sounds like a simple cooling system problem.

You're probably just not getting enough cooling water through the engine.
It doesn't take much algae & junk to clog things up!

Check the water pick up and strainer, it might just need cleaning.
- water needs to be able to flow freely through the system.
Check the water pump next, you might have a damaged impeller.
- hopefully you have good engine access.
- make certain the belt driving the water pump is tight.
Check the water lines to & from the engine.
- they should not be kinked or bent, restricting flow.
- they should not look like clogged arteries inside!

The good news is there's nothing real complicated about the cooling system!
It's just a matter of checking and cleaning all the bits & pieces!

Hope this helps!

-JAMES-
"Bella Barchetta"
 
Oct 6, 2010
119
Beneteau Oceanus 321 Carters Pt.
Another point to check is the engine thermostat--could be sticking due to age or small pieces of seaweed.Had this problem on our previous boat with a Yanmar single cylinder
 
May 3, 2008
252
Catalina Capri 22 Half Moon Bay
If the heat exchanger is leaking...

a. internally to the fresh water side, you should see coolant being expelled overboard (pollution bad!) and maybe smell it.
b. externally to the engine compartment, you should see it there in the bilge and again, probably smell it.

You might need to get some technical data on how to service the heat exchanger...
completely drain and refill with the known capacity of coolant.
then check and see if it's still disappearing?

Having it empty the expansion/overflow tank does not necessarily mean a leak. In other words, you might just need MORE coolant?

It's unlikely that the coolant would be leaking into the engine (cylinder head & block without you noticing a white, frothy oil as mentioned initially.

I stand by my "simplicity" statement! ...it's access to the system that's a bitch!!!:doh:
But even if you pay a good marine mechanic to solve it...
it will still be WAAAAY cheaper than burning up an engine!

-JAMES-
"Bella Barchetta"
 
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