Coolant bottle full on a 48 DA

[jff]

My overflow coolant bottles on each side of the engines (both facing the inside of the the bilge) have always stayed about half full. Yesterday when I went to do a quick inspection of everything before starting up the boat I noticed that one of them was completely full to the top. It must have happened the last time I ran the boat as it wasn't that way when I did the pre-startup inspection. I checked the coolant in that engine and it appears to be full, so I'm wondering where all this extra coolant came from, why it would be in the bottle, what this could mean or indicate, etc.?

Thanks,
Jason

 

[tobnpr]

"Making water" as it's sometimes called would indicate a breach between the jacket side and the raw water side of the cooling system.

I wouldn't be alarmed just yet; I'd drain the overflow bottle down to the proper level and run the boat. If it overfills again, it would be time for a coolant analysis to check for saltwater intrusion.

No expert here, just my "novice" $.02...

 

[shinsr]

was the overflow bottle at all "expanded" - I had same issue a few weeks ago and the answer was that the cap on the bottle was not venting properly, and needed to be replaced.

 

[jff]

I'll be the first to admit I don't really understand how all these systems work together, but shinsr I'm not sure I understand ... if the cap on the bottle was not venting that would explain why the bottle 'expanded', but that doesn't explain what all that coolant/water was doing in the bottle in the first place does it (the bottle was half full before I ran the boat and full afterwards)?

Regards,
Jason

 

[earthmover17]

Listen to Tobpnr. He is on the right track.
There is a pressure test you can do on the system if you suspect a problem.

Jack

 

[tobnpr]

Yes- go with Jack's suggestion!

You can purchase a pressure test kit at any auto parts store. Pump her up (to whatever your cap pressure is) and see if it holds pressure.

 

[Skuza]

Two blown head gaskets.
Estimated repair costs $ 10-15k on the light side.




No expert either but like others have said.
Maybe when the coolant expanded while hot it did not siphon back into the motors once it cooled? The purpose of the tanks is to allow for expansion when hot and to hold it till the motors cool thus returning it to the sytem.

 

[shinsr]

I am not a mechanic, nor do I play one on TV. But, my mechanic said when the bottle does not vent properly it can effect the overflow bottle from allowing the coolant to siphon back to the motors. He may have been wrong, but one new cap and I have had no issues since.