antifreeze leaking from raw water pickup on drive

[1977 SILVERLINE]

As the title says my 1977 470 is leaking antifreeze out of the raw water pickup of the mc 1 outdrive. This 470 has the closed cooling system. I'm not sure but I believe the heat exchanger is probably leaking? I pulled the drain plug on the heat exchanger for the fresh water side and antifreeze also ran out of the drain. Just wondering if the heat exchanger is bad or is there any other possibilities? Thanks!

 

[Bt Doctur]

Re: antifreeze leaking from raw water pickup on drive

you know there are 2 drain plugs down there, rearmost is raw side.could remove the hose going to the riser to check for A/F there.
only 3 ways,the riser is bad, the riser gasket is bad, or the heat exchanger .

 

[southwest395]

Re: antifreeze leaking from raw water pickup on drive

Had the same problem. If you pull the end caps off the heat exchanger and theres coolant there. Heat exchanger is bad one of the copper tubes or more have a leak. You can take it to a radiator repair shop and see if they can plug it or buy a new one. If they have to plug more then 10% of the tubes they wont be able to do it. Then you will have to replace it with a new one. I had mine repaired two tubes were bad. Mine had to be sealed twice for the plugs not to leak. Just make sure if you get it repaired its presure tested. Its was $80.00 for repair or anywhere from $500.00 to $1,150.00 new. They are expensive cause its all copper

 

[southwest395]

Re: antifreeze leaking from raw water pickup on drive

Also make sure your impeller is good to.

 

[stonyloam]

Re: antifreeze leaking from raw water pickup on drive

Southwest has his 470 pretty well figured out +1

 

[southwest395]

Re: antifreeze leaking from raw water pickup on drive

Not a expert but ive learned alot sence ive bought my 470. Cause ive had to do all this to get my going so far. Love the motor and the horse power but hate the maintance issue. But i'am glad to pass what ive learned.

 

[1977 SILVERLINE]

Re: antifreeze leaking from raw water pickup on drive

I took the end caps off of the heat exchanger and pressurized the cooling system with a radiator pressure tester and there was a/f leaking through the tubes, so im pretty confident I found the problem. Thank You

 

[southwest395]

Re: antifreeze leaking from raw water pickup on drive

yeap heat exchanger normaly go bad for not being properly winterised. Mine the guy didnt put and marine rv fluid in. So it had water in the copper tubes causeing it to crack.

 

[stonyloam]

Re: antifreeze leaking from raw water pickup on drive

yeap heat exchanger normaly go bad for not being properly winterised. Mine the guy didnt put and marine rv fluid in. So it had water in the copper tubes causeing it to crack.

No antifreeze is needed in the exchanger, the interior is already filled with 50/50 antifreeze (should be anyway), so just pull the AFT plug to drain the raw water side. I do mine right on the ramp when I pull the boat in the fall. Pull the boat transom plug, the exchanger plug, let her drain, DONE!

 

[1977 SILVERLINE]

Re: antifreeze leaking from raw water pickup on drive

I had the shop take a look at my exchanger today and they said is has a external and internal leak and shows signs of being froze at one time. They told me they couldn't fix it. Is there such a thing as a good used exchanger, or should I go with a new one? Any suggestions of where to get a new or used one would be helpful. Its an old 1977 470 so I am looking for a 3" exchanger. Thanks

 

[Bt Doctur]

Re: antifreeze leaking from raw water pickup on drive

if not here at the iboats store, check ebasicpower.com

 

[stonyloam]

Re: antifreeze leaking from raw water pickup on drive

e-bay