Reply With QuoteWhen was the last time you changed the water pump impeller?
I have a mid 70's cobalt inboard/outboard. It idles nice and cool, then when you get out on the water it gets real hot real fast and stays that way. I cracked the drains on the exhaust manifolds to determine whether or not I had any water flow. The starboard side was pissing fine while the port was pissing steam. At first I thought blown head gasket, but all the plugs were fine. I think my maninifold or my riser is cracked and/or leaking.
Is it safe to ditch the engine cover, slap on a set of automotive headers up-side down, and see if my engine temps will stay down???
Is this possible? If so, how do I reroute the cooling?
This is a very budget project and I would like to be sure this is my problem before buying expensive manifolds.
When was the last time you changed the water pump impeller?
Sounds like a blockage problem, before you start changing stuff out trace the problem, undo the lines and blow air thru them and if you have a pump with a rubber impeller that's more than likely the problem, take the pump apart and check it if you have vanes missing then they are pluging up a passage somewhere, follow the path until you find them, that will solve it!..
Pulled the pump, the vanes are all intact but distorted. They are permanetly curved. The pump housing is blistered on the outside from heat.
I am going to go ahead and pull the heads off and check for a head gasket leak. Wont hurt to have them freshened up anyway.
A retired boat mechanic told me that I can have the manifolds pressure tested for leaks.
Inspected all of the hoses, no blockages of any kind.
Hopefully by the time I replace the impellor, seal the heads back up and pressure test the manifolds, I will have solved the problem.
Thanks for the responses.
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