Closed loop cooling

[Bighawk53]

Trying to see if anyone has done a closed loop cooling system on a 5.7 Indmar engine? If so who has a kit? 2004 moomba outback

[MLA]

Replace the manifolds, circ pump and a couple other monor parts and get another 15 seasons out of it for less then converting it.

[Stazi]

What a massive waste of money. As MLA said. Maintenance of your current setup is key. Save your money and buy a newer boat with closed loop cooling down the line. There is no point spending the money to convert a 2004 to closed loop. What’s the point?


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[Bighawk53]

Better for the engine, closed loop is more efficient and less maintenance. I don’t mind the maintenance I’m just curious if anyone makes a kit. I don’t see how spending at least 40k on a boat with closed loop is the cheaper alternative to updating mine. If no one makes a kit that’s fine but I haven’t been able to locate one myself. My next choice is to build my own closed loop system.

[MLA]

closed loop is more efficient and less maintenance.

As a 23 year boat owner and does his own work as well as professionally, you got my attention!

[larry_arizona]

If anyone makes a conversion kit, it would be the OEM of your engine.

I would start by contacting https://www.skidim.com/departments.asp?dept=1003

The only real advantage I would see is if you are running in saltwater.


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[parrothd]

As a 23 year boat owner and does his own work as well as professionally, you got my attention!

LOL.. There's more maintenance with closed loop..

[MLA]

LOL.. There's more maintenance with closed loop..

Well, I have my opinion regarding winterizing and maintenance, but im genuinely curious in his opinion.

[Bighawk53]

I’m just here asking for a kit I didn’t want to start a debate on what is better. But I will say it’s obvious with a closed loop system the engine temps are regulated at better temps throughout all throttle settings. The better your engine temps are regulated the more efficient your motor is....that’s with every engine ever made that’s not secret. Internal corrosion is eliminated, and obviously ur always run non contaminated fluid through your engine. No chance of sand, grit or whatever else is being sucked in the engine from the lake. almost all new boats with inboard engine come closed loop so that alone should tell you what is better....I’m not here to question someone’s knowledge on this topic. But it seems that no one has a true answer.....they always say the same thing “ just replace this just replace that “.....clearly I know that is an option if i wanted to keep that same set up...I’m just simply asking if there is a kit or not. I don’t need the obvious “change this and that keep it the same” answer. I figured someone on here would maybe have some input on this topic. What’s the point of asking questions on a forum? If I wanted to keep my engine open loop I wouldn’t be here asking if there’s a kit. I don’t need to be told “just keep it the same”

[Bighawk53]

I appreciate it

[Bighawk53]

If anyone makes a conversion kit, it would be the OEM of your engine.

I would start by contacting https://www.skidim.com/departments.asp?dept=1003

The only real advantage I would see is if you are running in saltwater.


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Thanks I appreciate it

[larry_arizona]

Other than cost, I can’t think of any negatives.


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[parrothd]

More cost effective to do a tune up and install a strainer. You'll get a better performance increase from the tuneup then the closed loop "upgrade".

[MLA]

Other than cost, I can’t think of any negatives.


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On a 15 year old boat, I cant think of POS that offsets that cost.

Corrosion is negligible. Even with a closed system, (typically they are actually a semi-closed), the manifolds go first, so they still will need to be replaced at some time.

Temp regulation. Both types run a thermostat, so the engine temp is still regulated to within a few degrees of the t-stat temp. Unless the 04 open cooling with a 160 t-stat was given a new fuel and ignition map (MEFI program) and upped to a 190 t-stat, engine efficiency will likely not improve.

closed cooling still has a raw water system. Still need to drain at layup and maintain an impeller. Those parts are still susceptible to sand, etc. V-drive, trans cooler, raw water pump, exhaust manifolds and heat exchanger still need drained. Raw water block is the only thing not listed.

If i knew of a "kit", I would have pointed you to one, but my advice would still be the same. Boat engines rarely rust out. Its the raw water cooled exhaust manifolds that do, and closed cooling does not address them.

Good luck.

[larry_arizona]

On a 15 year old boat, I cant think of POS that offsets that cost.

Corrosion is negligible. Even with a closed system, (typically they are actually a semi-closed), the manifolds go first, so they still will need to be replaced at some time.

Temp regulation. Both types run a thermostat, so the engine temp is still regulated to within a few degrees of the t-stat temp. Unless the 04 open cooling with a 160 t-stat was given a new fuel and ignition map (MEFI program) and upped to a 190 t-stat, engine efficiency will likely not improve.

closed cooling still has a raw water system. Still need to drain at layup and maintain an impeller. Those parts are still susceptible to sand, etc. V-drive, trans cooler, raw water pump, exhaust manifolds and heat exchanger still need drained. Raw water block is the only thing not listed.

If i knew of a "kit", I would have pointed you to one, but my advice would still be the same. Boat engines rarely rust out. Its the raw water cooled exhaust manifolds that do, and closed cooling does not address them.

Good luck.

We agree, however indmar clearly thinks closed loop on the Raptor is a significant advantage.

My guess is they require closed loop for running catalytic converters and for max fuel efficiency and these raptors are pretty impressive on low fuel cost.


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[MLA]

We agree, however indmar clearly thinks closed loop on the Raptor is a significant advantage.

My guess is they require closed loop for running catalytic converters and for max fuel efficiency and these raptors are pretty impressive on low fuel cost.


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Easy there now, that raptor is a closed loop feedback ECM with CAT converters. No way on earth, to compare it to an open loop non-feeback ECM with no CATS. In the case of the OP's 04, thats what he'll still have, an open loop engine ECM with no CATS. Only changing to a semi-closed cooling system.

[Bighawk53]

Haha hey guys I’m just asking if it’s been done and if there’s someone that has designed a kit for this. I understand that not all people see a reason to do the swap. There is better technology then there was in 04. Why not update mine? No harm no foul. It’s the same as updating old cars with new technology. Done on a daily basis but u still get those people saying “why would you do that when the original equipment is fine” my question is why not? My next question would be “has anyone thrown a LS based motor in these boats?” HaHa guess I won’t go there since my answer will be “ why would you do that when these engine are just fine” but hey if anyone has any insight I’m willing to listen. Thanks for the responses.

[MLA]

Well, the closed cooling setup you would be putting on your 04, was the same in 04, so no new technology there.

yes, LS based marine engines have been around for years.

[mpbanskie]

I fitted an aftermarket closed loop to my 5.7 engine -again cost benefit might be marginal, but my reasoning was -

1) I run exclusively in very salty water
2) The engine is the 2015 EXT CAT variant of the 5.7 with very expensive manifolds
3) The system is a full system covering block and manifolds
4) Replacement cost of parts for me would include shipping from USA to UAE, this swings the cost/benefit significantly
4) New boat

I wont go searching for the kit number because its likely a very different kit to the pre EXT CAT engines, the kit was supplied by Indmar.

Thanks

mpbanskie.