Damage from Overheating?

[Rakuflames]

Originally Posted by oldjags

Our engine overheated today due to the hose clamp on the hose from the engine to the water heater coming loose, and all the coolant leaking out. The engine started slowing down and in about 4-5 seconds came to a complete stop - seized up.

We sailed for the next hour or so, repaired the hose, refilled the coolant, and then fired the engine back up. It seems to run fine and sounds normal. Any way to know if the engine has been damaged? It's a Yanmar.

You can have the oil analyzed. Take a sample to your Yanmar dealer.

[Rakuflames]

Originally Posted by oldjags

When I sensed that the engine was slowing down, I throttled down to idle, and that's when it stalled, so hopefully when it seized, it wasn't under much load. I waited for over an hour before adding more coolant and restarting.

Does the Yanmar not have a high-temperature alarm? I don't have my owner's manual with me. If it does, then mine is not working! If not, how hard is it to add one?

It has one. Apparently, it malfunctioned.

[John A]

Double hose clamp everything that uses a hose clamp!! Use only stainless steel clamps!!

Routinely inspect everything that you don't wish to fail!!

[Uncle Bob]

Originally Posted by oldjags

When I sensed that the engine was slowing down, I throttled down to idle, and that's when it stalled, so hopefully when it seized, it wasn't under much load. I waited for over an hour before adding more coolant and restarting.

Does the Yanmar not have a high-temperature alarm? I don't have my owner's manual with me. If it does, then mine is not working! If not, how hard is it to add one?

I think you will find that the motor has not totally siezed and that the fact that it started again about an hour later and runs well is a good indication. When an engine gets a little too hot things get tight in there and it sounds like you saved the day without any major damage.
Temp alarms require coolant around them to measure the temp, no coolant no alarm! My daughter demonstrated this in the family car some years ago.
Very good advice to change the oil and disect the filter, any metal is not a good thing. I too would suggest that this be done several times.
Good luck and happy sailing.

[John A]

Doesn't the oil pump pickup oil from the reservoir of oil in the oil pan?

Things that are heavy (metal) would sink to the bottom of the oil pan.

When/if a car motor stops working, you can walk away from it. A boat engine only stops working when you really need to use it.

Please people, get this checked out!

[model 10]

Originally Posted by John A

Doesn't the oil pump pickup oil from the reservoir of oil in the oil pan?

Things that are heavy (metal) would sink to the bottom of the oil pan.

When/if a car motor stops working, you can walk away from it. A boat engine only stops working when you really need to use it.

Please people, get this checked out!

The stuff you find in an oil screen or an oil filter are little pieces of whatever metal there is. They are held in suspension for quite some time. Almost everything is still in the oil not in the sump. You can actually figure out what the particles are by close inspection. Steel/iron is magnetic, bearing material melts with a soldering iron, copper is copper, aluminum is aluminum and ring material is very thin and shiny.

[Finistere]

Originally Posted by oldjags

When I sensed that the engine was slowing down, I throttled down to idle, and that's when it stalled, so hopefully when it seized, it wasn't under much load. I waited for over an hour before adding more coolant and restarting.

Does the Yanmar not have a high-temperature alarm? I don't have my owner's manual with me. If it does, then mine is not working! If not, how hard is it to add one?

If you lose your coolant the high temperature alarm will not work, it has to be in contact with liquid to work.

[John A]

Originally Posted by Guy

The stuff you find in an oil screen or an oil filter are little pieces of whatever metal there is. They are held in suspension for quite some time. Almost everything is still in the oil not in the sump. You can actually figure out what the particles are by close inspection. Steel/iron is magnetic, bearing material melts with a soldering iron, copper is copper, aluminum is aluminum and ring material is very thin and shiny.

I fear you're missing the point that I'm trying to make.

The OP has experienced a problem with the engine on his boat. That engine now has a potential for failure.
I prefer to leave the safety of land knowing that I have eliminated all potentials for failure on my boat.

Your choice may be different.