Cooling sys. flush feasibilty question GM IL6

itstim

Seaman
Joined
May 31, 2004
Messages
52
Older inline 6 GM 160hp seawater cooled:<br /><br />Suspect my block has rust build up in its cooling passages. Since angioplasty is out of the question I was wondering if it is feasible to flush it by removing t'stat, running intake water from impeller overboard, plugging overboard hose from manifold into water intake at t'stat housing, filling system with some "stuff" (Iron-out, CLR, radiator flush..?) and water and running eng. just long enough to circulate "stuff" and water and letting it sit for X # of hours and then re-hooking everything up correctly and flushing it out. Is this effective? What kind of "Stuff" would be best?<br /><br />Thanks
 

RatFish

Chief Petty Officer
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Jul 29, 2003
Messages
647
Re: Cooling sys. flush feasibilty question GM IL6

MST sells some stuff that MAY be worth a try. Check iboats first.
 

Scaaty

Vice Admiral
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Re: Cooling sys. flush feasibilty question GM IL6

Originally posted by itstim:<br /> Older inline 6 GM 160hp seawater cooled:<br /><br />feasible to flush it by removing t'stat, running intake water from impeller overboard, plugging overboard hose from manifold into water intake at t'stat housing, filling system with some "stuff" (Iron-out, CLR, radiator flush..?) and water and running eng. just long enough to circulate "stuff" and water and letting it sit for X # of hours and then re-hooking everything up correctly and flushing it out. Is this effective? <br />Thanks
It darn sure can't hurt anything! I'm not sure which to use though.........
 

itstim

Seaman
Joined
May 31, 2004
Messages
52
Re: Cooling sys. flush feasibilty question GM IL6

Thanks RatFish...anybody else ever tried this?
 

itstim

Seaman
Joined
May 31, 2004
Messages
52
Re: Cooling sys. flush feasibilty question GM IL6

Anybody know what kind of "stuff"?
 

RatFish

Chief Petty Officer
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Messages
647
Re: Cooling sys. flush feasibilty question GM IL6

I never tried it.
 

tommays

Admiral
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Jul 4, 2004
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6,768
Re: Cooling sys. flush feasibilty question GM IL6

well on a car the stuff used to every year before winter<br /><br />but on a boat there is so much rust i have only seen it done by takeing off the parts and haveing them done in a tank usally only the heads would worth doing if the block is that bad it would be hard to make all the labor worth it<br /><br />tommays
 

itstim

Seaman
Joined
May 31, 2004
Messages
52
Re: Cooling sys. flush feasibilty question GM IL6

Anybody ever done this?
 

Dunaruna

Admiral
Joined
May 2, 2003
Messages
6,027
Re: Cooling sys. flush feasibilty question GM IL6

Did mine about 2 years ago: engine out of boat, removed circ pump, thermostat and core plugs (all of them). Stuck the end of my pressure cleaner in to every available oriface and blew the rust and crude away, even used a small pick to loosen the stuff that sets like concrete. Chemicals won't budge the hard stuff.<br /><br />Aldo
 
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