Fresh water cooling upgrade??

gtfireftr

gtfireftr

Member
Oct 9, 2014
292
Westport MA
Boat Info
1997 Sea Ray Sundancer 290
Engines
Twin 4.3 liter w/Alpha Drives
I just pulled the trigger on upgrading to fresh water cooling system on my repower....
I ordered from Monitor... anyone have any experience with installation or use of these kits...
Full system with alpha outdrives..... any advice is appreciated....

TIA
 
Do you have crank mounted raw water pumps? I was told that Alpha water pumps don't move enough water for a full system that cools the manifolds. The dealer told me that unless I was boating in very cold water, I'd have overheat issues under load when water temps got above low 70's. They further stated that to avoid that issue, I would need to add thru hull pick ups and crank mounted water pumps. That was more money and work than I could afford so I went with half systems instead. They seem to work very well and I like the idea of not running salt water through my engine blocks and heads etc.
Just curious, did you get a four pass heat exchanger? I was leaning that way but there wasn't enough room in my bilge to fit the over sized heat exchanger. What T-stat are you going to run? Mine are running 165's now, 145 previously when raw water.
Good luck with it and let us know how things work out down the road. If you can make it work, I may do my manifolds when I change them out next time.
 
The company assured me that the kit was specifically designed for raw water alpha pump to supply sea water to cool the heat exchanger. They supply a 160 thermostat. Not sure what heat exchanger is included.
Thanks for the input.
 
Money well spent. Also great perk for re-sale. All you ever need to change/check now is risers. Those will have salt water thru them but that's easy.


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I put monitor's full system on my merc 5.0 / bravo 3. No problems, Running temp is 160 at therm housing with IR temp gun / 150 deg on the gauge.
 
It was the alpha pumps that are supposed to be to low a flow for a full system. I hope it works for the OP, as I'd like to go full system at next manifold change.
 
I would have liked to go with full systems when I re powered my old 300 5 years ago but the anemic little pumps in the alphas didn't supply enough and I would have had to get engine mounted pumps and cut intake holes in the hull so I went with half systems.
Maybe the technology in heat exchangers has changed in the last 5 years. But I would double check it.
 
JVM225 said:
I would have liked to go with full systems when I re powered my old 300 5 years ago but the anemic little pumps in the alphas didn't supply enough and I would have had to get engine mounted pumps and cut intake holes in the hull so I went with half systems.
Maybe the technology in heat exchangers has changed in the last 5 years. But I would double check it.
Click to expand...
As I said, the manufacturer insists this is not an issue.....
Did you install and have an issue?
I pulled the trigger on the full system, and I am going to install this week, so hopefully put the motors in this weekend and splash in a month or so.....
We will see I guess.....
 
I installed a full system from monitor on my previous boat. 5.7 with an alpha drive. Never had a problem with overheating. I do boat in colder water most of the time which I'm sure helps. Maximum water temperature would have been 18 to 20 C.
Installation was fairly straight forward and the instructions were quite good.
 
gtfireftr said:
As I said, the manufacturer insists this is not an issue.....
Did you install and have an issue?
I pulled the trigger on the full system, and I am going to install this week, so hopefully put the motors in this weekend and splash in a month or so.....
We will see I guess.....
Click to expand...

Yes, I installed the half systems and never had a problem. I would have gone for the full systems but was talked out of it because of the alphas. Back 5 years ago when I repowered that boat and installed the half systems everyone I spoke with told me that I would need to go with engine mounted sea water pumps and install the through hulls for them if I wanted full systems.
The heat exchanger technology has probably advanced in the last 5 years and gotten more efficient.
The bilge was already pretty cramped in front of the motors on that boat and it just seemed easer overall to change the exhaust manifolds every five years. It was a relatively easy job on that boat and the OEM E coated manifold and riser kits for the 5.7's Mercruisers are pretty reasonable. I'd changed them all before on the old motors on the boat and on other boats.
It turned out that I sold the boat at the very beginning of the 5th season anyway. I did strongly advise the new owner to do the exhaust before the start of this coming season. Hopefully he heeded the advise.
 
Last edited:
I was told the same thing last summer by Michiganmotorz.com. They said that unless I was boating in cold water, ie Canada or Alaska, I would experience overheating. Where I boat, we can see water temps into the high 70's and even around 80 in the shallow bays in the hottest part of summer. I went with the half systems like JVM used. They were not hard to install but make engine access a little more difficult.
Please let us know how it works out for you.
 
I just repowered 2 years ago and have an alpha 1... used the monitor half system. Was also told the alpha 1 does not supply enough water for a full system. Boat had full system when I bought it...... which is why I had to repower....


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rmlsll said:
I put monitor's full system on my merc 5.0 / bravo 3. No problems, Running temp is 160 at therm housing with IR temp gun / 150 deg on the gauge.
Click to expand...

Doesn't bravo drives use pumps mounted on engine?


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gtfireftr said:
As I said, the manufacturer insists this is not an issue.....
Did you install and have an issue?
I pulled the trigger on the full system, and I am going to install this week, so hopefully put the motors in this weekend and splash in a month or so.....
We will see I guess.....
Click to expand...

If you have an alpha 1 outdrive I would strongly suggest doing more research to make sure a full system will work. Unless Monitor changed something in the last 2 years I don't think it's going to be good on your new engine. Again I speak only for alpha 1........


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From Monitor's web site...
"[h=1]COOLING SYSTEM TYPE:[/h]
[h=1]This kit is a "full" fresh water cooling [FWC] system; meaning that the engine block and exhaust manifolds are protected by the system. Exhaust elbows remain on the raw water system. System utilizes a unique, high performance heat exchanger. Our FWC systems are specially designed for the low capacity raw water pumps used on sterndrive engines"[/h]Hopefully they are right....​
 
What concerns me is that they don't specify Alpha 1 drives by name. "Sterndrive engines" is a broad all encompassing term that may or may not include the Alpha I.
 
SCORPIO said:
What concerns me is that they don't specify Alpha 1 drives by name. "Sterndrive engines" is a broad all encompassing term that may or may not include the Alpha I.
Click to expand...

I agree! It would s--k to spend all that money and do all the work of installing the system just to find out that you need an engine mounted pump.
 
I suppose the OP could always convert that set up to a half system down the road if he had to but still a lot of work and a PITA.
 
Well... after much deliberation I specifically called the manufacturer (Monitor) and their
tech line guy told me that these were designed for the sterndrive application.....
Then I asked about the Alpha 1, and he told me that the gen 1 may cause an issue, however he assured me that the Alpha 1 gen 2 would be fine..... I guess we will see....
Thanks for the replies....
 
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