aq125 raw water cap leaks on the heat exchanger

[smithfloyd]

No matter what I have done since i bought the Bayliner the raw water cap on the heat exchanger leaks. I have changed the cap and seal. Had the heat exchanger cleaned out. Replaced the exhaust manafold. Even at idle the cap leaks.Checked all hoses and pipes for leaks and blockages.

 

[JAL51974]

Re: aq125 raw water cap leaks on the heat exchanger

Must be some oddity about the surface of the heat exchanger, where the cap twists onto it? Is there some rough or gouged out spots there? Doesn't make sense since you changed out the cap, etc. already. there just isn't normally that much pressure there to force water out unless there is some irregularity in the metal part that the cap twists onto.

Joe

 

[gcboat]

Re: aq125 raw water cap leaks on the heat exchanger

Agree with Joe. Take a straight edge and sit it on top of the fill vent - cap off, engine cool. Look at it from a bunch of different angles. When they start to leak folks have the tendency to remove them and replace them with a lot of unneeded force. This will destroy the integrity of the vent housing itself. If all still looks good you could try to pry - VERY GENTLY - up on the outer edges of the lip. Place a piece of wood down so you don't go poking holes or bending something you don't want to. I mean REAL EASY - all the time you're doing this keep a really good eye on the joint connecting the fill tube to the exchanger unit. Don't want to break that.
You don't want to use vice grips or anything like that - you just want to lift up the outer edge, not crush or deform the top of the filler neck. Please remember that the metal is soft and doesn't particularily like being abused that way - so be berry, berry careful. < that's my Elmer Fudd imitation >