First item for checklist for spring boating

Joined
Mar 21, 2004
Messages
29,553
Location
Near the beach in Delaware
Finished up winterizing my I/O yesterday and one thing I think needs to be on my spring checklist is loosing coolant. It's a closed cooling system V8 marine engine.

The expansion tank seems to indicate I am loosing coolant after several test runs of the engine. It did pass a cooling system pressure test. So either I am loosing coolant or there is still air in the system and slowly it's working it's way to the expansion tank. The engine.was very low on coolant when I bought the boat as indicated by overheating in both exhaust manifolds.

So it did pass a cooling system pressure test. But at the same time seems to be loosing coolant.

In the spring I can pull the heat exchanger and have it cleaned and pressure tested.

What should be my game plan after that?
 
Finished up winterizing my I/O yesterday and one thing I think needs to be on my spring checklist is loosing coolant. It's a closed cooling system V8 marine engine.

The expansion tank seems to indicate I am loosing coolant after several test runs of the engine. It did pass a cooling system pressure test. So either I am loosing coolant or there is still air in the system and slowly it's working it's way to the expansion tank. The engine.was very low on coolant when I bought the boat as indicated by overheating in both exhaust manifolds.

So it did pass a cooling system pressure test. But at the same time seems to be loosing coolant.

In the spring I can pull the heat exchanger and have it cleaned and pressure tested.

What should be my game plan after that?
Older Mercs had cooling system air bleeds however that was a ways back. Most probably get seized up anyway. If it passed a leak test and didn’t overheat during the last run I’d dip it in the water and go. Take a jug of coolant in case you need to top it off after it’s bled the system on its own. You may not need to remove the exchangers.
 
I take it you run in salt water in Delaware, how old are your manifolds and risers?. When you pressure tested the engine, were the manifolds blocked off ?. I had an old Chrysler 318 fresh water cooled boat, that blew a head gasket. From the looks of it, it was leaking for a while before it finally let loose. If you always have some steam in the exhaust , even when it's warmed up, I'd tear it apart over the winter and give it a good look see.,,
 
I take it you run in salt water in Delaware, how old are your manifolds and risers?. When you pressure tested the engine, were the manifolds blocked off ?. I had an old Chrysler 318 fresh water cooled boat, that blew a head gasket. From the looks of it, it was leaking for a while before it finally let loose. If you always have some steam in the exhaust , even when it's warmed up, I'd tear it apart over the winter and give it a good look see.,,
Well I sure wish it was not salt water but that what is here. I pressure tested the closed cooling so engine, exhaust manifold and part of the heat exchanger. I put together a cooling system pressure tester so the pump was valved off once it was at the proper pressure. It held the pressure for 20 min with zero loss. How does one see steam in the exhaust when the raw water and exhaust are mixed together in the exhaust elbows and exit the boat underwater?

My boat is at a rack storage marina and they stop moving boats on/off the rack from mid Dec to April.
 
Back
Top