Heat Exchanger Leaking???

R

rndcomp

Petty Officer 3rd Class
Joined
Jun 24, 2007
Messages
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I have an '87 Mercruiser 470 (170HP) with Fresh Water Cooling and have been losing coolant at an alarming rate. I do see that some is coming out of the weep vent (which i assume means that my front cam seal needs replaced), but I am also wondering if I should check to see if my heat exchanger is leaking fresh water into the raw water side (and then discharging it). I am trying to track down my overheating problem and I am currently dismissing the idea of a bad impeller (only because I am also losing coolant). Once the coolant issue is fixed, and the system still overheats, than I guess I will need to look into a new impeller.

Any thoughts?

Thanks!
 
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R

rndcomp

Petty Officer 3rd Class
Joined
Jun 24, 2007
Messages
88
Re: Heat Exchanger Leaking???

One more thing....should I also be concerned with a blocked heat exchanger..... Is there any easy way to test for a blocked or leaking exchanger?
 
J

JoChek219

Petty Officer 2nd Class
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Jul 17, 2006
Messages
130
Re: Heat Exchanger Leaking???

pressure test it! I had antifreeze coming right out of my drive on my 87 3.7L... pressure tested it and noticed anitfreeze coming up where the seawater dumps back into the exhaust and out to the drive....if its bad they aren't cheap
 
R

rndcomp

Petty Officer 3rd Class
Joined
Jun 24, 2007
Messages
88
Re: Heat Exchanger Leaking???

When you say pressure test it, are you referring to the heat exchanger only, or, should I pressure test the entire cooling system and look for leaks?

Thanks!!!!
 
J

JoChek219

Petty Officer 2nd Class
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Messages
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Re: Heat Exchanger Leaking???

you can do the whole system. put the press. tester right on top where you pour in your antifreeze....also what about your impeller in the drive...last time that has been changed possibly causing an overheat
 
R

rndcomp

Petty Officer 3rd Class
Joined
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Messages
88
Re: Heat Exchanger Leaking???

Completly agree, but unless a bad impeller can cause coolant leak, I don't think that this is my "immediate" problem. Granted, my guess is that I will be looking at the impeller once I get the leak resolved.

Thanks!
 
R

rndcomp

Petty Officer 3rd Class
Joined
Jun 24, 2007
Messages
88
Re: Heat Exchanger Leaking???

JoChek219 said:
you can do the whole system. put the press. tester right on top where you pour in your antifreeze....also what about your impeller in the drive...last time that has been changed possibly causing an overheat
Click to expand...

Do I need to disconnect any hoses in order to verify anything, or, do I just put pressure in the sytem and then look for leaks. I would think that if the heat exchanger was leaking FWC to raw water, that I would not be able to see that via a pressure test with everything hooked up.

Thougths on best way to proceed? I would like to pressure test tomorrow night.

Thanks!
 
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