rawwater cooling

[drem312]

Well I have read the pros and cons but alot of post are close a liitle off to my situation but heres my question.Just had my nice 350 5.7 motor all new and rebuilt and had originally planned on installing a 800 dollar fresh water cooling system for block only.( I dont have a separate pump just the sterndrive pump in the omc cobra so I believe it has to be the block only) any way after reading and reading I have found that as long as you flush after each use you can run it in the saltwater and get years out of it. I will boat in mostly saltwater here off the coast of NH so the season for me is like may to sept. I would haul the boat back each time and flush and wash it all down. Anybody have a raw water cooling boat that has been used in saltwater and flushed after each use and have no problems? How long have you had the boat ? I like to keep the motor simple and I really dont know how the little sterndrive waterpump would cool the whole new heatexchanger without a pump off the engine

 

[Gary H NC]

Re: rawwater cooling

People run them in salt all the time.Keep flushing it.
Exhaust manifolds need to be changed more often and are not cheap on a Cobra though.

 

[itsneverfinished]

Re: rawwater cooling

I like having that infinite supply of cold water... Makes my engine happy. I run mostly in brackish and dirty water. Always rinses clean.

 

[Lou C]

Re: rawwater cooling

I have a salt water cooled motor at least half its life in salt (23 years old) and still no cooling problems, but you do have to be careful to check the manifolds/risers at least every 5 years for rust and corrosion. Mine stays on a mooring, never flushed till the end of the season. BUT, when I winterize, I drain, and then back-fill with the best -100 antifreeze with corrosion inhibitors. I know some will scoff at this, say it's not necessary, but I can tell you I replaced the OE 23 year old circulating water pump this fall, and there was no flaking rust in the water passages of the pump or cylinder heads, and the thermo housing I replaced 8 years ago, none, intake manifold under the thermo housing, none. So I do think you can make a raw water cooled motor last in salt. One issue I've had is the thermostats never last long, they get sticky and cause the motor to run too cool. If I re-power this boat I would put a half system on it because starting with a new engine, the thought of running salt water through it is disturbing to me...I think it's worth the $800, also lets it run at the temp it was designed to, makes it easier to winterize, and re-sale is easier...

 

[achris]

Re: rawwater cooling

I run in salt (Indian Ocean). My previous engine was freshwater cooled, and I put stainless elbows on, so no problems, ever! My new engine is just over 4 years, and I didn't put freshwater cooling on because the thieving 'children of unmarried people' wanted over $4,000 for the kit! Most engines here are raw water cooled and still manage to last well into the 20+ years range. But yes, check the elbows every 5 years (with a view to replacing) and the manifolds usually last 10-12 years....

 

[drem312]

Re: rawwater cooling

thanks these are the answers I was looking for ...I know its better for resale and probably worth the $800 but its another $800. I still might put one on found another site that wants just under $700 but knowing that it certainly is possible with good results to to run it in saltwater and flush it after each use indian ocean?? what state is that in LOL

 

[PigPen4x4]

Re: rawwater cooling

You can do it for less the $7-800.
I just snagged a new heat exchanger on the big auction site for $217.
If I stay with the 4.3, I feel it'll cool fine with the alpha pump, if I go V8,
I'll try it full system first with some experimentation, if it gets too warm I'll go half system. Or I may watch for a belt driven pump.
I know I'm fine without closed cooling since I stay in fresh water,
but I'm anal. My lengthy automotive background keeps telling me green liquid is better than clear/brown.
PP4x4